Bandit Alley
MODEL SPECIFIC => SUZUKI BANDIT 250 & 400 => Topic started by: Banditmax on May 31, 2007, 09:17:32 AM
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As there are quite a few of us with non standard bikes out there i thought it'd be good to start a thread sayuing what engine mods you'd done and what jetting you are using. Please only posts with specs in start a new thread if you have problems with your jetting
Heres Mine at the moment its running well no big flat spots and pulls real good at top end. But not completely happy with the fuel screw setting at the moment.
Height above sea level: Around 750-1000 feet
Outside Air temp: 14.1c
Bike is: 1993 first gen non V model Japanese import. 33mm carbs.
Engine Mods: In airbox K&N filter with standard lid. Waco full racing exhaust system with baffle installed. M-max derestrictor box. Carbs have just been fitted with all new o rings.
Jetting:
Needle: Factory Pro ti needles on 3rd clip down
Main: 97.5
Pilot: 32.5
Mixture screw: 1 and 1/4 turns out
Float height 15mm
Edited thanks for the tips guys
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Just a couple comments from your trusty Mod and I'll get out of the way of this thread (which is a great idea). We actually started one of these a year or so ago but I don't think it got very far.
Knowing which B4 you have will be helpful (V model, first or second generation, US 32mm carbs or not...).
Also it would be interesting and useful to document your satisfaction with it. E.g.: "Runs awesome up top but has bad flat spot at 4K"...
Go get 'em!
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:popcorn2:
Awesome timing guys! We're going to have to jet Dita here right away, and I haven't a clue where to start ( and have been too busy to search the forums so far)
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altitude: 1500ft
average temperature year round ( a completely useless number): 47.3 F. summer temps avg: 65F, but that's 95F during the day and 50F at night... IOW, jetting is a pain.
Mods: K&N filter in stock airbox with no snorkle. Yosh full 4-2-1 exhaust,
Main: 105
Pilot: 32.5 (stock)
Needle: Factory Pro, position 3 (I think, gotta look)
Mixture: 3.25 (EDIT: woah was I wrong!! had listed 1.25..., 3.25 might be too much and may be a cause of some softness between 4-5k when very warmed up)
floats: 16mm, raise to try to cure softness at 5k or so (was15mm)
runs real good, but I think she might need more top end. I might try a 110 main, we'll see. I think there may be more unknown mods to this bike because of a couple clues: 1) I'm running more jet than a lot of folks (I think). 2) this bike has been drilled for safety wiring for the track, so I can't say whether anything has been done inside the case, but its certainly more likely than if she wasn't drilled.
MORE EDIT: I'm getting some softness between 4-5k. Shows up when very warmed up (after a long ride) or when very hot out. If cruising nicely at that engine speed in say 3rd gear (what is that, about 35mph?) and I crack the throttle just a bit (maybe 1/16th) it will stumble and miss. if I give it more, it clears up. I think its either too much on the mixture screw (though that should be mostly out of the picture by then) or maybe float level. Its not a big deal and if I don't try to ride so nicely, then its no problem :motorsmile:
MORE MORE EDIT: a supposed factory trained suzuki mechanic claims that my softness is either the pilot jet or the float height. Float height is easy (since I only have stock pilots available at the moment). Will try 16mm just to see what it does. Also, am I rich on the fuel-air? it doesn't stumle on the throttle blip... but its still out pretty far and maybe that is affecting the 4-5k just off idle thing.
MORE MORE EDIT EDIT: I'm still fussing with a little bitty rich spot between 5-6k and its driving me crazy. I raised the floats, lowered the fuel level to 16mm and its better, but still a drag when its really hot. (we were pushing 95F today). It only shows when fully warmed up and I crack the throttle just the tiniest bit off cruise at 5-6k rpm. it goes away easily with a touch more throttle. Its annoying because when cruising in that range, there's always little tiny throttle adjustments and it sputters just a bit... ack. also tried turning idle screw in to 3.0 from 3.25... no go, starts to lean surge a bit and won't idle as smooth...
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For the time being (I'll edit when it changes, again)
1991
5500' above sea level
32mm carbs (completely rebuilt, nothing skipped)
stock airbox, filter, exhaust
Main: 95 (and still too rich)
Pilot: 30
Mixture screws: 2.25 turns out
Float height is stock
Needles are stock and shimmed up 3mm
And I'm still running rich. Odd to see so Little mixture when I've never had a bike use less than 2.5 turns before, but I'm also running the smallest pilot possible (made a HUGE improvement). I'm planning on getting some Factory needles, and dropping another main.
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Heres the setup for my 91 with 33mm carbs
660 feet above sea level
195 thermostat
yosh zyclone 4 into 2 into 1 pipe
air box with 2 extra holes and snorkle removed
degreed cams
timing advanced 2 degrees
127.5 main for spring temps up to 68 to 70F
125 main when it gets hotter out
needle in the stock location 3rd groove with this pipe
stock float height
stock pilots
air screw 2 turns out
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altitude: 76 m (249.3 ft)
temperature: -35 to +35 degrees celsius (right now its closer to 30) average is 9 degrees
Bike:1991
MODs: Stock airbox, stock filter, yosh exhaust, factory jet kit, US model needle jets
Main: 95
Pilot: 32.5 (stock)
Needle: Factory Pro, middle clip
Mixture: 2.25
floats: 15mm
Verdict: Slightly lean between 4-5k and around 8k almost unnoticeable once hot, unless you're cruising in that rpm range. I might try raising the float to 14mm or going up on the MJ.
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Heres my setup,it runs flawlessly at all temps and rips to redline with no hesitations or flatspots, so Id say that Factory Pro's setup list/guide is dead on for anyone in a similar environment.It ran horribly before the jet kit....
Factory Pro 1.0 jetkit in stock carbs,91 model Bandit 400........
97.5 main jet
3rd clip on FP needles/springs
15MM float height
stock pilot jets
2.25 turns on the screws,stable 1600rpm idle with a nice lope
Stock air box with K&N,lid perforated around the snorkle inlet
Yosh 4-2-1 headpipes with Hindle Stealth muffler
Iridium plugs,stock heatrange w/Accel wires
Sea level,average temps and humidity
Hot thermostat
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http://www.jetsrus.com/FAQ_jet_kit.htm
Another read on jetting besides the Factory Pro way of doing it.
Another tidbit for those of you like me that have a Dynojet kit:
Width(thousands)------Kehein # -- DynoJets # -- Mikuni #
0,0350---- 92,5--------- 92----------- 86,3
0,0360---- 95----------- 94----------- 88,1
0,0370---- 97,5--------- 96----------- 90,0
0,0380---- 100---------- 98----------- 91,9
0,0390---- 102,5------- 100---------- 93,8
0,0400---- 105--------- 102---------- 95,6
0,0410---- 107,5------- 104---------- 97,5
0,0420---- 110--------- 106---------- 99,4
0,0430---- 112,5------- 108--------- 101,3
0,0440---- 115--------- 110--------- 103,1
0,0450---- 117,5------- 112--------- 105,0
0,0460---- 120--------- 114--------- 106,9
0,0470---- 122,5------- 116--------- 108,8
0,0480---- 125--------- 118--------- 110,6
0,0490---- 127,5------- 120--------- 112,5
0,0500---- 130--------- 122--------- 114,4
0,0510---- 132,5------- 124--------- 116,3
0,0520---- 135--------- 126--------- 118,1
0,0530---- 137,5------- 128--------- 120,0
0,0540---- 140--------- 130--------- 121,9
0,0550---- 142,5------- 132--------- 123,8
0,0560---- 145--------- 134--------- 125,6
0,0570---- 147,5------- 136--------- 127,5
0,0580---- 150--------- 138--------- 129,4
0,0590---- 152,5------- 140--------- 131,3
0,0600---- 155--------- 142--------- 133,1
0,0610---- 157,5------- 144--------- 135,0
0,0620---- 160--------- 146--------- 136,9
0,0630---- 162,5------- 148--------- 138,8
0,0640---- 165--------- 150--------- 140,6
0,0650---- 167,5------- 152--------- 142,5
0,0660---- 170--------- 154--------- 144,4
0,0670---- 172,5------- 156--------- 146,3
0,0680---- 175--------- 158--------- 148,1
0,0690---- 177,5------- 160--------- 150,0
0,0700---- 180--------- 162--------- 151,9
0,0710---- 182,5------- 164--------- 153,8
0,0720---- 185--------- 166--------- 155,6
0,0730---- 187,5------- 168--------- 157,5
0,0740---- 190--------- 170--------- 159,4
0,0750---- 192,5------- 172--------- 161,3
0,0760---- 195--------- 174--------- 163,1
0,0770---- 197,5------- 176--------- 165,0
0,0780---- 200--------- 178--------- 166,9
0,0790---- 202,5------- 180--------- 168,8
0,0800---- 205--------- 182--------- 170,6
0,0810---- 207,5------- 184--------- 172,5
0,0820---- 210--------- 186--------- 174,4
0,0830---- 212,5------- 188--------- 176,3
0,0840---- 215--------- 190--------- 178,1
0,0850---- 217,5------- 192--------- 180,0
0,0860---- 220--------- 194--------- 181,9
0,0870---- 222,5------- 196--------- 183,7
0,0880---- 225--------- 198--------- 185,6
0,0890---- 227,5------- 200--------- 187,5
Here's the rub:Dynojet needles also have a known different taper and tip in comparison to Factory Pro needles and even more different yet versus than stock (both companies). They size their jets with the actual orofice diameter in inches versus the CC flow as Mikuni does. I know the website below is for an F650 but it's for reference sake, I didn't take a micrometer to my needles to confirm.
http://faq.f650.com/FAQs/JetKitFAQ.htm
The shape of the needle seat is also slightly different for probably the same proprietary reasons. The OEM 102.5 is also known to be slightly bigger as well versus an aftermarket Mikuni 102.5. The Dynojet 100 (which comes in the jet kit) visually, has the same size orofice but more than likely has a seat designed for the DJ needle.
When the EPA tests bikes, they sniff them at highway speeds (probably 55) I'm guessing in top gear which is why the idle screws are as lean as they are and the mains as big as they are (to be "compliant " but still make some power). With the tighter taper of an aftermarket needle, it would only make that jet even richer since the hole is less covered at small openings. Obviously the higher the needle comes out of the seat, the more that flow number comes into play.
In the end, it comes down to what works. My bike is away for the winter now but I did make some changes to it that will probably affect the jetting come it's hibernation in the springtime. Putting all that schwah in here helps me remember it as well as hopefully will help a couple of you out as well.
Since this is a jetting thread here are my mods/numbers:
-Stock pilot
-Stock float height
-Did not drill the slides
-Stock slide springs (DJ ones would make the midrange flat)
-105 main (Mikuni)
-DJ needle, third position with one shim
-3.5 turns out
-Intake cam mod-not degreed
-Modified airbox lid with larger snorkel, no additional holes
-Removed silencer in collector
-Cobra F1S pipe with original core replaced with 2" perf'd stainless (more like an aftermarket pipe)
I haven't had a chance to really ride it with the pipe modded since the weather has come in now. Before with the smaller baffle (more than likely the reason why they say it's unnecessary to rejet), it made great power almost everywhere and was maybe a hair fat on the top end. With the free-er flowing baffle, it should theoretically even out and may have to go up on the main. We'll see come springtime.
Obviously everyone's bike is different but I'm mainly curious to see the jet sizes everyone has because they seem to be all over the place (for good reason: every setup is different).
-Randy
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this will turn into a even greater thread with time :beers:
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I am now running
Height above sea level: Around 750-1000 feet
Outside Air temp: 14.1c
Bike is: 1993 first gen non V model Japanese import. 33mm carbs.
Engine Mods: In airbox K&N filter with standard lid. Waco full racing exhaust system without baffle installed. M-max derestrictor box. Carbs have just been fitted with all new o rings and floats.EDIT Fitted hotter thermostat now too.
Jetting:
Needle: Factory Pro ti needles on 3rd clip down
Main: 97.5
Pilot: 32.5
Mixture screw: 2 and 1/4 turns out
Float height 15mm
Bike runs nicely and pulls strongly throughout.
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Got a Bandit 400 Variable Valve,
it's a 98 year and is completly standard
i am living not too high above sealevel and am needing some info on jetting, floats and what not.
good thread but needs some more info
gonna keet trying till i get it right
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Instead of continuing to edit my old post, I thought I'd start fresh.
1993 400, Yosh 4-2-1, K&N filter in stock airbox with snorkel removed (anyone know if that's worthwhile? seems like it would cause more turbulence and possibly restrict more as a result... .02)
Main: 97.5
Pilot: stock, 32.5
Needle: Factory Pro, middle position
Float Position: 15mm
Air/fuel screw: 3.25 (still tweaking that)
Seems pretty good through out. I haven't done a good plug chop on the main yet, but I think it's pretty good. Pulls very strong in all gears.
Altitude typically 1500ft, very dry, cool average temperature.
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http://motorcycleinfo.calsci.com/Airboxes.html
Make your own conclusions, but I think that modifying outside parameters especially for something tuned to work a certain way may yeild less than stellar results.
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That's an interesting read but when we had my engine on the dyno and a air pressure gauge hooked into the air box we had the most power with the snorkel removed and 2 extra holes in the lid. With the modified lid the engine made about 3 extra HP and the pressure was higher in the airbox meaning that there was less of a vacuum and more air.
That article only holds water if your bike is left stock, no pipes, no slipons, even the filter material makes a difference. And as any engineer know that there's the physics of how an engine works and there's the reality of how it works
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True, but really where was the power made? And of course, everyone's setup is vastly different as well as how Suzuki was feeling that day when they built the motor.
If you gained a peak HP higher in the rev range but it was softer in the middle is it necessarily better? Big reason why R6's are lauded on the street but are loved at the racetrack but 675s and overbores are more popular backroad toys.
I understand that ultimately the highest HP prevails but if it costs driveablity down below versus gains elsewhere is it worth it?
Comes down to what you're tuning for.
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Thief400: in my opinion, removing an snorkel is vastly different than removing a snorkel *and* drilling more holes. Removing a snorkel potentially "detunes" an airbox resulting in a loss of power at certain revs. You may simply be making up for that by putting more holes in the box thereby allowing good airflow at all times. But you still may be missing that all important "tuning" of the air box.
tomacGTi: nice read. thanks. I like the math... we just did fluid flow in a tube in calc last week.. ;) It makes sense to me. Anybody got accurate dimensions of a B4 snorkel? Mine is long gone... I'll happily do the math and see what I can figure out.
What we really need is a series of controlled studies of different airbox lid configurations, with the bike rejetted to match, and then dyno'ed. But that's a pipe dream I suppose.
I've often wondered about just removing the airbox lid altogether. The whole thing is pretty well protected in there already. Of course then what would you do with the EGR hose...
A
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total length: 150mm
internal flare: 38mm
External falre: 55mm
Interior tube diameter: 38mm
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The only reaon the snorkel was in the air box was for noise, Your giving Suzuki to much credit here remember this was the late 80's when this bike was designed. Now a days everything is a tuned working package that can't really be improved upon. But back then there was a lot of power left on the table just waiting for someone to find it
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The laws of physics work at all times, even in the 80's :roll:
Still I have removed the snorkel, I don't care about mid-range power. What's that anyway on a 400? Top end is the way to go :motorsmile:
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Herr todd have you got holes in your airbox too? Im toying with removing the lid completely but im unsure about the jetting for european temperatures and pressures.
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Well to put this all to rest we did do a dyno pull with just the snorkel removed and it made .5 more HP with NO dip in the mid range as you keep suggesting would happen! We just put duct tape over the 2 extra holes and jetted way down to get the EGTS back up to where we wanted them, I will see if I can find the dyno sheets I think they are still on my old puter that I don't use any more. When I get time to plug it all in again I will go searching for them
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Just did a little experiment on my bike using the 97.5 Mikuni jets that everyone runs in their Factory Pro kits. As soon as it came onto the main jet (right around 8k), it fell flat on it's face and would lean surge until it came back below. This was at all throttle openings . Everywhere below that (8k), it rode just like normal.
The Dynojet needles must have a wider tip in comparison to the Factory Pro needles as these require a much bigger jet up top then otherwise. They honestly look very close to the OEM needles with the exception of the taper going up. I don't even think that running a 100 MJ would make a difference and a 105 is just a bit too fat. I'm also using Mikuni jets as I wanted to achieve a baseline as it's difficult to locate Dynojet jets. They're also less expensive and easier to reference.
For those of you wondering why I'm running a modified snorkel, I honestly don't like the sound an open airbox makes. The resonance gives me a headache, even wearing earplugs, so I measured the airbox opening without the factory piece and made my own snorkel.
My setup:
-14.5 float height
-Stock pilots
-Stock airfilter
-3.25 turns
-48mm int. dia snorkel (made it out of 2" PVC)
-Gutted stock collector/headers with Cobra F1S slip on with custom 2" perf'd baffle
-102.5 MJ (stock)
-195* thermostat
-3rd clip with a washer (3.5 clip)
-Stock slide springs (shorter one transitioned rougher onto the main)
It's a little lean until it warms up but once it does, it's nice and smooth up and down the range. Got a tiny bit of tailpipe soot and I've been told as it comes off the needle and onto the main it puffs a bit and clears right out.
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Interesting. I haven't had time to get back to it, and with the bike desperately needing new tires, I haven't ridden hardly at all to test out changes.
@Banditmax: as HerrTodd says, the laws of physics apply all the time, even in Europe!
A
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Yeah i know it works the same but im a good 1000feet below most of you in the us i think. Was just looking for some baseline figures for jetting.
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I'm at about 90 to 275 meters above sea level, which is 300 to 900 feet. I've had holes in the lid for a while, took it off completely too but in the end I just run a stock lid without the snorkel. That little bit of extra top end power just didn't weigh up to the fuel costs. Maybe if I only used the bike to ride for fun, but not on a bike that's used to go anywhere I need to go. I ride about 25000 km's a year on my bikes, mostly on the Bandit. So I was satisfied with the power it makes with the stock lid, all I really care about is good throttle response from idle up to 15000 revs, which was perfect. Just took me a while to get the 1000 to 3000 rpm range to respond well.
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What jetting are you running with the snorkel removed then?
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#100 main jets, 32.5 pilot jets, Factory Pro ti needles 3rd clip, 15 mm float height, Factory Pro throttle valve springs, stock throttle valve and needle jet, air jets stock too. running on 95 octane fuel. I have a replacement K&N air filter, 195* thermostat, GSX-R 400 GK73A CDI, Yoshimura 4-1 headers with a titanium mid pipe and the stock end can. The stock can takes away some top end power but it keeps the police inside which is more important.
Having a broadband A/F meter really helps :thumb:
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Witch system did you buy?? the A/F one
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Hangin_Biposto's jetting
Height above sea level: Around 100 feet
Outside Air temp: 70-80 deg f
Bike is: 1991 With Cobra F1S slip-on and mid pipe restrictor removed. Stock 32mm carbs.
Jetting:
Needle: Factory Pro needles on 4rd clip down (I tried 3 like everyone else here has, but it was a tiny bit lean.) You could feel a slight hitch when you roll into it.
Main: 97.5
Pilot: 32.5
Mixture screw: 3 turns out. (Could probably go back to 2.5 and have it run ok, but it was a little hesitant on warm up this way.)
Float height 15mm
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I have a '92 GSF400N USA model. Mikuni carbs. I just recently rebuilt the carbs (thanks Jay) and put new spark plugs in. It has stock airbox and *I believe* stock jets and needles. It currently has a Vance and Hines supersport 4-1 exhaust. Any suggestions on a good baseline setting to start from? It runs really rough right now and I'm foreseeing having some trouble tuning it given how it is running now.
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rough as in??? idle, bottom, mid, top end... :yikes:
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Hi all,
was reading your threds on air box tuning and theres abook by John Robinson called motorcycle tuning (4 stroke) second edition which is a good read, it covers bikes of this age and has some interesting reading on air boxes, its worth a look!
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http://members.optusnet.com.au/sv650-k2/Rejetting_Notes.pdf
Stumbled upon this on a boring, cold rainy day. Thought it was the best written step-by-step for jetting that I've seen yet.
It's written for an SV650 (no surprises there, there are millions of these things) but you should be able to make some judgement calls to suit our bikes.
-Randy
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where can i find a nice kit to fit with 54mm air filters?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=200270085396
can this one fit my 95 japan model?
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where can i find a nice kit to fit with 54mm air filters?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=200270085396
can this one fit my 95 japan model?
Factory pro config 30. You'll have to measure the bellmouth of the carbs to be sure.
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For those of you stuck with a Dynojet jetkit, the first thing you will notice is that the numbers that others have with the Factory Pro kit will absolutely not jive. With a 97.5 main, my bike would lean surge like hell as soon as it came on the main whereas FP guys say that it works great. Interfuse had posted the needle tapers and similarities somewhere but it is an entirely different needle with a wider tip needing a larger main versus the FP.
If you've got a DJ kit and don't want to spend the money on another jet kit, here are some numbers I've come up with. First off:
-91 Bandit 32mm US carbs
-Unifilter (green foam BF-1 universal sheet, cut to fit)
-modified airbox lid, custom snorkel
-F1S exhaust with 2" baffle, silencer removed in collector
-Tuning done at 50-65*F, low humidity. I may have to jet down a step in the full-blown summertime here in PA as it's vastly different.
-OEM slide springs. The DJ springs are stiffer making the slide a bit more fat than it needs to be. I found the response better with the OE springs YRMV.
All jets are factory Mikuni. I didn't even bother using DJ jets as they're a PIA to source. Also, I used a Uni filter because it was significantly cheaper ($15 at the dealer versus $50+) and flowed just slightly less than a K&N. Expect at least one more jet size up using a K&N.
My modded F1S now flows the same as every other aftermarket slip-on you can buy because of the 2" core, it was 1.75" with louvers before. Changes to the air filter will cause more changes to jetting versus exhaust. Of course they should be tuned together, but that's in a perfect world.
With Uni air filter in modified box (2" inlet)
-110 main, 107.5 when it gets hotter.
-3.5 turns on the screws
-1 shim
With stock element in modified box (2" inlet)
-105 main
-3.25 turns
-1 shim
I know the airbox topic has been beaten to death in here but I have found that with a snorkel, the midrange is more rideable at throttle openings below WFO. I have two lids, one with an inlet bellmouth and no snorkel and one with a length I figured in to start resonating at 8k and the snorkel has a smoother roll-on everytime. Both are the same size opening, difference being one is 4cm to clear the front hump in the lid and one is 15cm tuned to resonate.
Try it for yourselves if you want, I posted on how to make one not too long ago. Since the openings are the same size and just the length changes, no need to rejet.
Also, using this guide I found as well (I don't remember where, FJ forums I think) helped a great deal and is fairly accurate even with our bikes. Starting jetting point would be 102.5 Mikuni:
1 jet size for custom 4 into 2 exhaust
2 jet sizes for 4 into 1 exhaust
1 jet size for K&N filter (single inside airbox)
1 jet size for drilling out the bottom of the airbox
2 jet sizes for both single K&N and drilled airbox
2 jet sizes for individual filters
2 jet sizes for no muffler (open header)
1 pilot jet size for every 3 main jet size increase
Add up all the jet size increases and subtract one. (Remember they go in steps of 2.5 for each jet size)
Under a mismatch condition, like individual filters and stock exhaust or 4 into 1 header with stock filter and air box, subtract an additional 1 jet size.
Check plug color often, sync carbs after each jet change, make sure the floats are set correctly, and seriously consider purchasing a Color Tune.
Make sure your carbs are in perfect working order before making jet changes.
Example from my '79 XS1100 F:
Stock main jets: 137.5
Stock pilot jets: 42.5
2 sizes for 4:1 exhaust (Jardine)
1 size for single K&N
1 size for drilled air box
4 (main sizes) - 1 = 3 or 137.5 + (2.5 * 3) = 145.0
1 (pilot jet size) or 42.5 + (2.5 * 1) = 45.0
With this jet configuration I get 32-38 mpg on the open road, Smooth idle, very strong acceleration from off idle to 80+ mph, and steady pull past 120 mph. My "F" has 65K mile on it, of which I have put 33K with this jet configuration.
Happy Jetting
Additional info: Decrease main jet size one step per 2000' above sea level. Decrease pilot jet every 6000' above sea level
Hope this helps someone out.
-Randy
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good stuff Randy :beers:
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Work in progress:
-Vance and Hines 4-1 supersport pipe w/different muffler (F1s with 2" perf'd core)
-120 main
-3.25 turns
-3rd clip DJ needles 1 shim (better roll-on, too lean before)
-Uni filter in factory box with 55mm snorkel.
-90* and humid
Pulls like a freight train from 8k on up, bit softer in the middle in comparison to modified stock header with same muffler. Definitely better up top but softer from 5-7k.
Comes off of idle well but the lean spot that all Bandits have is still there and worse if you're lugging the motor. Have to be on the pipe all the time to get the max out of the setup.
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I'm trying to figure out what is in my carbs and how to get it somewhat leaner. My mileage could be better and there is still some soot accumulating on the exhaust. When I bought the bike a year ago it was already 20 years old and changed hands an unknown amount of times. The people I bought it from had it 9 years but barely used it. I've put twice the miles on it in the 9 months I've had it.
The bike had an unknown make 4-1 header with a Yamaha muffler when I bought it. I put it back to a stock pipe. Airbox is stock foam with some large holes right above the snorkel.
Altitude is just shy of 6 feet above sea level when I'm standing up (near the beach). The highest mountains near me are about 5,000 feet. I've had the bike up to ~9,000 feet near Yosemite and it was very unhappy about that.
I have an extra set of rusty carbs I got cheaply for extra parts. The main jets in them are marked 102.5, the needle jets are brass in color with no adjustment steps.
The carbs that came in the bike have main jets marked 96 and the needle jets are steel/aluminum color with adjustment steps for the C clip, currently on second from end.
Neither of the main jet markings matches the Mikuni numbers in the chart on the previous page of this thread. Maybe it currently has a DynoJet kit?
Width(thousands)------Kehein # -- DynoJets # -- Mikuni #
...
0,0370---- 97,5--------- 96----------- 90,0
...
0,0390---- 102,5------- 100---------- 93,8
The carb kit I bought had the wrong float needles and the bike flooded. The needles from the rusted carbs look better condition than the ones that were in there so I used those when I put it back together again. Now it's no longer leaking out but is still flooding a bit from the smell, the acceleration sucks and it won't hold a steady idle. I used stock float level and maybe that isn't right with the jetting kit. Also some of the linkage may be sticking up a bit.
I replaced the two o-rings on the float plastics and the tiny o-ring by the diaphragm with Viton ones.
I didn't do any adjustments to the mixture levels since it idled well before cleaning and no jets were changed. The plugs were gone so someone somewhere did when they did the jet kit.
Any other comments or suggestions on this? Thanks all and happy mothers day (in the US). :thanks:
EDIT: Tearing it all apart again this evening found the mixture screws were out 4 turns, seems a bit much. Replaced those o-rings and put them to 2 1/2 turns. Will re-set the float levels and put it all back together tomorrow.
EDIT AGAIN: Got it back together with the correct float needles. No more gas leakage but it idles like crap. Runs up to 5~6k RPM then very slowly drops down and dies. High speed seems decent but quite a few flat spots in acceleration. Will put the mixture screws back to 4 turns where they were and make sure the slides are moving freely. Float levels are set to 15mm on the highest float, they don't sit evenly. The o-rings are seated ok. Any other suggestions on why it would do this?
FINAL EDIT: Just to not leave it hanging... The symptoms I had pointed to a vacuum leak. I put the idle mixtures back to 4 turns. Then meticulously cleaned and assembled the diaphragms, needles, covers, etc, and put it all back together. Made extra sure to fully seat the carbs into the intake manifold and the airbox onto the carbs. Added clamps to most of the hoses. Started up rough but slowly got better over a ~5 mile ride at high RPM/Speed. Now seems ok except for a bit less 'off the line' acceleration than it had before. I'm assuming that may be helped by syncing the carbs.
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Hi, are you sure the carbs are not from a gsxr400 as some of them have 96 mains and no bungs in the pilot jets.
I have a dyno jet kit and the needles are much finer than the B4 ones which are a very thick needle compared to most bikes.
Im sure the dyno jet kit came with 100 or 102 mains.
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I can't be sure as the bike was 20 years old when I got it. The needles are single taper, very pointy, with 5 slots for the C clip. I don't think those are stock. Everything else in the carbs is identical to the other set I have.
The company I got the carb kit from on eBay, Sirius Consolidated (www.siriusconinc.com), is overnighting the correct float valves at no cost. Very good service as I bought the kits about 3 months ago.
I looked up the DynoJet kit on their website and it comes with 96 and 100 main jets. This matches all the parts listed in their kit.
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Did any of you here had to install bigger jets after installing an aftermarket exhaust or will changing the throttle needle suffice?
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I didn't get a real good test run (no traffic, hence no low rev cruising ;)
What a damn shame. I have plenty of great of great opportunities to try out pilot jet riding here,... you're welcome to come by and test....
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91' Bandit (MFG June 90'):
Stock Exhaust
32mm BST's (Rebuilt w/ new o-ring kits)
Factory Pro 1.0 kit
Alt: ~ 360ft
Setup:
180 deg. CBR F3 Thermostat(idle hunts a little less)
Stock airbox(well sealed, had to use tape due to warpage), K&N filter and stock exhaust
95 MJ (tried 97.5 for a bit, it was too rich)
Needle Clip #3 position from top(Factory Pro needle)
Fuel Screws 2-1/4" turns out
Carburates PERFECTLY through rev. range, but still hits the wall @ 110 mph...not sure yet if it's electronic restriction or stock header/muffler restriction...sent a message to Jay and hopefully he can illuminate...but it runs like a scalded dog up to around 90mph or so.
Just did a carb sync before my last shakedown yesterday(and a valve adjustment), so everything is in "spec".
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my understanding (limited as it is) is that the electronic restriction is on later bikes (like the '93) but the whole thing is questionable. *If* you're restricted, I think it only applies to 5th and 6th gear, but that's mostly speculation too.
A
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I wanted to leave my previous jetting information up, but include the below new jetting information based on using a Yosh "tri-y" header(I believe there were three different header styles done for the Bandit 400 by Yosh, a 4-1, and 4-1 with a welded on balance pipe just under the head flanges, and my version which is a tri-y) mated to a "tyga perfomance" stainless oval silencer "EXSL-0017" via custom mid pipe:
Yosh Tri-Y w/ custom mid-pipe & tyga SS oval silencer(EXSL-0017)
32mm BST's (Rebuilt w/ new o-ring kits)
Factory Pro 1.0 kit
Alt: ~ 360ft
Setup:
180 deg. CBR F3 Thermostat(idle hunts a little less)
Stock airbox(well sealed, had to use tape due to warpage), K&N filter and stock exhaust
97.5 MJ (95's too lean)
Needle Clip #3 position from top(Factory Pro needle)
Fuel Screws 2-3/4" turns out
Iridium Plugs
Picked up a little more top end acceleration and now it tops out around 115mph(gained 4mph). The mid range is a little fluffy around 6K now, with more roll on it's "ok"...but seems a little off carburation wise in that area(too rich?). I'll start with turning the fuel screws in a 1/2 turn in and see what that does. I have to wait a bit on the plug check as they were showing lean with the 95's in and I want to ride it a bit to see how they come out with the 97.5's.
****UPDATE****
I'm now busting over 120mph(not sure how much further it will go yet)...with 32mm's none the less and I actually raised the gearing to reflect GSXR400 spec....go figure. There's a chance this increase was due to using synthetic(Rotella T6)...or maybe I've been "breaking in" my bike as I acquired it with 18K miles and now have over 21K with "hard use".
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[...]The mid range is a little fluffy around 6K now, with more roll on it's "ok"...but seems a little off carburation wise in that area(too rich?). [...]
I have a fairly similar setup to yours, and this mid-range "fluffy-ness" is the bane of my existence. It *seems* like a rich problem (and I've had people report black smoke out the tailpipe when rolling on) but Marc at FP says it might be a problem with a too small pilot jet. I haven't gotten around to trying it yet, but thought you should know. Some experimentation with fuel screws suggests that it would run better with larger pilots (37.5) but it didn't really seem to take care of this particular symptom. I'll probably fiddle with the needle a bit and see if that's it. Also, I suspect my needle jets are out of round, which might contribute to this problem.
very much my uneducated 0.02.
A
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Thanks for the note Andrew, I appreciate it. Have you topped out your bike? I'm curious what it hits with 105 mains.
Nick
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I'm not running 105s. I think they're 97.5s but honestly it's been a while since I looked. My top end has never been more than about 110-112 and it's hard getting up there. Seems to run out of steam around 100mph. I haven't played with the top end much because I just don't need it and don't have much opportunity to explore it. Also, the gas mileage was pretty bad with those 105s, if I remember correctly. One of these days I'll take the time to really work on it, but with no garage space and precious little time... shrug... If I do, I'll be sure to report in with the results.
A
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Your post in 07' says you have 105's...that's where I got that.
:)
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...and I was just about to post a jetting question - great thread and thanks.
WW
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Im hoping for a little input from the Bandit400 owners... where can I find a pipe or a slip-on muffler for my 93? I have been unable to find ANYTHING here on the US side of the pond... :duh:
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A few posts back we were talking about mid-range "fluffiness" (whatever that means). Turns out my problem was overly worn needle jets. Replacing those helped a whole bunch. my current setup is 102.5 mains, #35 (up 1 size) pilots, 3.25 - 3.5 turns out on the fuel screw, same 4-2-1 Yosh Exhaust (now with no rust!), no snorkel in airbox, K&N filter. Runs pretty well, but I might move up to #37.5 pilots to clean up still-unstable idle and the large amount of fuel screw. Sorry, no top end report, but it's pulling very well still at 90mph.
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Im hoping for a little input from the Bandit400 owners... where can I find a pipe or a slip-on muffler for my 93? I have been unable to find ANYTHING here on the US side of the pond... :duh:
Hey Wario, I think you'll have a hard time finding something dedicated for the B4, but there are other options. I posted this back in 2007 when we changed the exhaust on Dita, our little B4.
http://forums.banditalley.net/index.php?topic=8930.0
A few posts back we were talking about mid-range "fluffiness" (whatever that means). Turns out my problem was overly worn needle jets. Replacing those helped a whole bunch. my current setup is 102.5 mains, #35 (up 1 size) pilots, 3.25 - 3.5 turns out on the fuel screw, same 4-2-1 Yosh Exhaust (now with no rust!), no snorkel in airbox, K&N filter. Runs pretty well, but I might move up to #37.5 pilots to clean up still-unstable idle and the large amount of fuel screw. Sorry, no top end report, but it's pulling very well still at 90mph.
Yeah! That sounds like you got a little seat time at least?
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Im hoping for a little input from the Bandit400 owners... where can I find a pipe or a slip-on muffler for my 93? I have been unable to find ANYTHING here on the US side of the pond... :duh:
Hey Wario, I think you'll have a hard time finding something dedicated for the B4, but there are other options. I posted this back in 2007 when we changed the exhaust on Dita, our little B4.
http://forums.banditalley.net/index.php?topic=8930.0
[/quote]
Thanks for the suggestion - I've been figuring that I'd need to fab something if I continued on this dry spell... I "punched" out the inner baffle this past weekend with a 3/4" pipe - the bike sounds better and revs snappier and I haven't had to change the jets. I may have found a real nice "good enough" solution that will help me be more patient until that scrapyard B4 with a pipe comes along... Again - Thanks. :thumb:
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Thanks for the suggestion - I've been figuring that I'd need to fab something if I continued on this dry spell... I "punched" out the inner baffle this past weekend with a 3/4" pipe - the bike sounds better and revs snappier and I haven't had to change the jets. I may have found a real nice "good enough" solution that will help me be more patient until that scrapyard B4 with a pipe comes along... Again - Thanks. :thumb:
Are you using the stock exhaust still? Suzuki put the drain holes at the wrong part of the exhaust, so it's likely rusting like crazy too. I would haunt fleabay and see if you can find any exhausts with the mid pipe. Even used would be better than stock. It was unreal what it weighed too.
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Yeah! That sounds like you got a little seat time at least?
I'm daily commuting now -- have been for a year and a half. The ride isn't very far, current commute is only 8 miles, but it keeps both me and the bike in decent tune. :)
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Thanks for the suggestion - I've been figuring that I'd need to fab something if I continued on this dry spell... I "punched" out the inner baffle this past weekend with a 3/4" pipe - the bike sounds better and revs snappier and I haven't had to change the jets. I may have found a real nice "good enough" solution that will help me be more patient until that scrapyard B4 with a pipe comes along... Again - Thanks. :thumb:
Are you using the stock exhaust still? Suzuki put the drain holes at the wrong part of the exhaust, so it's likely rusting like crazy too. I would haunt fleabay and see if you can find any exhausts with the mid pipe. Even used would be better than stock. It was unreal what it weighed too.
Well, I figured that I needed to be very careful to swap out exhausts considering the overwhelming number of horses that are clawing to get out... :trustme:
I like the bike relatively quiet - it makes it easier to sound like Im not speeding, even if I am. Waking all the children in the neighborhood by reving to 13k in the first three gears just to get up to 60mph is far from optimal :duh: - but, sounding like a sewing machine that just had the oil changed is not too cool either. My goal is not to mod the bike until it's unrecognizable - but rather to slightly improve it to the point where I feel like Im getting the most I can out of it for the money I have into it. My B4 is a true "2nd" bike that is (almost) only used on nice days and for Sunday get-together events with like minded friends. I've got an awesome daily rider and have built my share of street fighters - so, my need to make it into something it's not or to extract every possible ounce of power from it are not in this bike's future...
And besides... I'm carrying more extra "excess weight" than the Bandit, so losing 10lbs off the pipe is negligible when put into the scope of total weight reduction :trustme:
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So today I tried 110 main jets on recommendation by Thief100.
Setup:
Stock airbox (removed snorkel for this)
Stock BST33 carbs, needle position +1 rich
Main jet 110 (stock was 100)
Slip-on exhaust
Altitude: 0ft
On stock settings my 400 ran fine without flat spots (if I richen the needles) but wouldn't go above 185km/h and dropped in power above 12000rpm.. So I figured to give the 110 main jets a try. I completely cleaned the air filter and removed the snorkel just in case.
On my testrun I ran with the silencer in the slip-on like I always do. Mid range was very strong but above 8000rpm at full throttle it almost stalled.
I removed the silencer from the slip-on and now it's much better. I can really notice it pulls harder and to a higher RPM, but it's still too rich and a bit jerky above 8000rpm full throttle.
Is there anything else I can do?
Can I run without the airbox cover or any other solution without having to immediately make holes in the airbox?
Or should I just try 105/107.5? (but will need to buy the jets and remove carbs again....)
Thanks.
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Update..
So I kinda figured it out.
I tried without the airbox cover but no-go. WAY too lean would hardly go when opening the throttle.
So when I refitted the cover I figured to try and putting back the snorkel... and to my surprise the jerkiness at 8000-9000 rpm was almost completely gone. I guess it does have a purpose, at least on my bike.
The midrange has increased really noticeably too:
I made an acceleration video last month so today I went back to the same place and did another video.
Here's the result, 4th gear roll on 40-80km/h.
https://dl.dropboxusercontent.com/u/22072961/MF/Acc2.mp4
It still feels a little weaker at 8000rpm, but perhaps it only seems like that because the midrange is stronger.. not sure :stickpoke:
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snorkels serve a purpose, acting as a velocity stack and are often tuned to the appropriate resonant frequency (with the airbox) to do things like punch up the mid-range. While I don't know that this is the case with the b4 airbox, I wouldn't be surprised to learn that it is.
A
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snorkels serve a purpose, acting as a velocity stack and are often tuned to the appropriate resonant frequency (with the airbox) to do things like punch up the mid-range. While I don't know that this is the case with the b4 airbox, I wouldn't be surprised to learn that it is.
A
Well, in this topic Thief100 said he put it on the dyno with & without snorkel and without he got 0.5 extra HP without dips...
Mid range is the same with or without for me.. but jerkiness at 8000rpm is now gone and it pulls in 1 go.
Anyway, stock settings there would be a noticeable torque increase from 8000-12000 rpm. Now it's more like 10000-14000 and way stronger between 4000-8000.
Gonna see what happens with silencer again.
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What I do notice:
Some time ago I tried needle clips on richest position (+2, stock carbs). The midrange was strong but when I would open the throttle quickly from low RPM (about 2000rpm) it would start to stall. I would need to open the throttle more easily and it would go.
Putting it back to +1 rich settings would fix this but the mid range would be a a little weaker.
Now with 110 main jet (and +1 on the needle) this problem has returned. I assume because the main jet affects the whole range.
Is there any way to have the strong mid range but not the flooding/stalling from 2000rpm+full throttle?
Does the pilot screw affect this or does that really only affect idle? It starts and idles fine.
I didn't think the 110 main jet would change so much but damn it almost doesn't feel like a 400 anymore with this mid range.
Thanks
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Does anyone have the specs or information about the stuff that comes in the Factory Pro 1.0 kit?
I bought the Config 30 kit and am running pod filters, but am considering going back to running the airbox - but I'd prefer not to have to buy the entire thing all over again, especially if the 1.0 kit contains similar needles. Given that I already gave Factory Pro my money I was hoping that someone could share the info. I can trade the Config 30 stuff. :)
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I've copied this Jetting format from Ninjette.org's 250 Jetting Database.
YEAR: 1992 Bandit GSF 400 USA
INTAKE MODIFICATIONS: K&N Pods RU-1824
EXHAUST MODIFICATIONS: Stock Exhaust, Cap Removed
JET KIT OR STOCK? DYNOJET Kit #3134 (Packaged as RoadKrome 12-9202)
BRAND OF JET KIT? DYNOJET
MAIN JET: 107.5 Mikuni Generic from JetsRUs.com
NEEDLE AND CLIP POSITION: Dynojet Needle, bottom clip (richest position, highest needle height) Dynojet Supplied Springs
MIXTURE SCREW SETTINGS: 3
ELEVATION: sea level to 300 ft.
MISCELLANESOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP: 0 throttle to 3/4 throttle response is fantastic, however bike doesn't not pull at all at WOT (full throttle.) Bike "stands still" at WOT. I do not recommend this setup.
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I've copied this Jetting format from Ninjette.org's 250 Jetting Database.
YEAR: 1992 Bandit GSF 400 USA
INTAKE MODIFICATIONS: K&N Pods RU-1824
EXHAUST MODIFICATIONS: Stock Exhaust, Cap Removed
JET KIT OR STOCK? DYNOJET Kit #3134 (Packaged as RoadKrome 12-9202)
BRAND OF JET KIT? DYNOJET
MAIN JET: 110 Mikuni Generic from JetsRUs.com
NEEDLE AND CLIP POSITION: Dynojet Needle, bottom clip (richest position, highest needle height) Dynojet Supplied Springs
MIXTURE SCREW SETTINGS: 2.25
ELEVATION: sea level to 300 ft.
MISCELLANESOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP: WOT pull is fantastic and fast. 0 to 3/4 throttle motor stumbles, then accelerates. Bike is just OKAY, but I miss the 0-3/4 throttle performance of 107.5s and bottom clip.
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I've copied this Jetting format from Ninjette.org's 250 Jetting Database.
YEAR: 1992 Bandit GSF 400 USA
INTAKE MODIFICATIONS: K&N Pods RU-1824
EXHAUST MODIFICATIONS: Stock Exhaust, Cap Removed
JET KIT OR STOCK? DYNOJET Kit #3134 (Packaged as RoadKrome 12-9202)
BRAND OF JET KIT? DYNOJET
MAIN JET: 110 Mikuni Generic from JetsRUs.com
NEEDLE AND CLIP POSITION: Dynojet Needle, 3rd clip (middle position, middle needle height) Dynojet Supplied Springs
MIXTURE SCREW SETTINGS: 2.25
ELEVATION: sea level to 300 ft.
MISCELLANESOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP: WOT is fine. Bike seems to bog at middle clip.
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I've copied this Jetting format from Ninjette.org's 250 Jetting Database.
YEAR: 1992 Bandit GSF 400 USA
INTAKE MODIFICATIONS: K&N Pods RU-1824
EXHAUST MODIFICATIONS: Stock Exhaust, Cap Removed
JET KIT OR STOCK? DYNOJET Kit #3134 (Packaged as RoadKrome 12-9202)
BRAND OF JET KIT? DYNOJET
MAIN JET: 110 Mikuni Generic from JetsRUs.com
NEEDLE AND CLIP POSITION: Dynojet Needle, 2nd clip (2nd richest position, 2nd highest needle height) Dynojet Supplied Springs
MIXTURE SCREW SETTINGS: 2.25
ELEVATION: sea level to 300 ft.
MISCELLANESOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP: 1/4 throttle to 3/4 throttle response is better than 3rd clip positionm, but still sputters.
WOT seems slow.
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I've copied this Jetting format from Ninjette.org's 250 Jetting Database.
YEAR: 1992 Bandit GSF 400 USA
INTAKE MODIFICATIONS: K&N Pods RU-1824
EXHAUST MODIFICATIONS: Stock Exhaust, Cap Removed
JET KIT OR STOCK? DYNOJET Kit #3134 (Packaged as RoadKrome 12-9202)
BRAND OF JET KIT? DYNOJET
MAIN JET: 112.5 Mikuni Generic from JetsRUs.com
NEEDLE AND CLIP POSITION: Dynojet Needle, 2nd clip (2nd richest position, 2nd highest needle height) Dynojet Supplied Springs
MIXTURE SCREW SETTINGS: 3.0
ELEVATION: sea level to 300 ft.
MISCELLANESOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP: WOT improved. Pulls now, but I think I will try 115s and see if pull gets better.
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I hope you don't mind Pelero, I copied your copied template :bandit:
YEAR: 1991 Bandit GSF 400 Limited Mikuni BST33 carbs
INTAKE MODIFICATIONS: none
EXHAUST MODIFICATIONS: A differnt canister, large diameter
JET KIT OR STOCK? Stock
BRAND OF JET KIT? Stock
MAIN JET: Mikuni 108 off Aliexpress :bandit:
NEEDLE AND CLIP POSITION: stock needle 2nd clip position (richer)
MIXTURE SCREW SETTINGS: 1.75 turns
ELEVATION: sea level
MISCELLANESOUS INFORMATION ABOUT YOUR BIKE’S JETTING SETUP: I tried 110 main jets, but at WOT acceleration felt flat. No hesitation in mid range. Then tried the 108's, WOT much better, put a :grin: on my face. Slight hesitation at 6000rpm at WOT. I plan to order 105's to check if WOT can be improved even more