Bandit Alley
MODEL SPECIFIC => SUZUKI BANDIT 600 thru 1200 - AIR/OIL COOLED TECHNICAL => Topic started by: Big Shasta on October 01, 2011, 12:19:23 PM
-
I have a 2002 Bandit 1200S. It was running great when I got it and since I can never leave well enough alone (especially with the tease of more power) I decided to install the holeshot stage 2 kit.
It already had a holeshot slip on when I got it. I installed the complete Stage 2 kit and the 5 degree timing advance. Also did the Pair blockoff and removal at the same time. I've made sure there are no open ports on the carbs
I'm in Florida so humidity is a factor. Here's what I've tried.
Fuel Screws set to 3.5 turns.
Started with 152.5 Mains 17.5 pilot jets 3rd notch from the top 1 shim
Anything above 3K rpm had a very bad stumble
Changed to 2nd notch 1 shim
WORSE 3K and up DEAD...bike would complete die at 3 K until I let off the throttle.
So I went the other way, 4th notch no shim...couldn't apply any more than about 1/4th throttle or the bike would die. Would ease up to speed but would stop accelerating at 3.5K RPM
Called Dale at Holeshot.
I had removed the carb vent hoses between the carbs but I also removed the T's he suggested putting them back on ...open Ts but no hoses. Also checked a bunch of other things that he suggested but didn't find anything out of the ordinary.
Dale suggested my current settings. 147.5 Main 4th notch no shim. The bike is MUCH better now. Accelerates to 3K ok but then stumbles badly through 3-4.5K and then after 4K pulls like a wild animal up to redline.....tries to pull my arms out of the socket...
Any suggestions as to why such a small rpm range would be struggling? Seems to get a little better when the bike warms up really good but never goes away completely. where to go from here?
I never did measure the float heights, I was confused on how to measure it so I left it alone figuring it must have been right before since it ran fine. I got a service manual and now see how to measure it, think that could be my problem?
Dale suggested maybe I would need the shim added back in to the 4th notch? Think that would help?
-
Most guys with Dale's kit have found him pretty good to work with, so I would start by following his instructions and discuss your concerns with him first.
-
I agree, dale does know his stuff AND it's amazing that you can just call him up and get 15 minutes of his time to pick his brain. He seemed to think that I may be trying to tune around another issue.
I really just wanted to see if anyone had had a similar issue with a needle setting affecting such a narrow RPM range. That's what seemed odd to me. If I add a shim, I'll be richening it (raising the needle) and with it pulling HARD from 4.5K to redline, it didn't seem lean to me.
Just looking for a sanity check.
Thanks.
-
Maybe for fun try driving in the stumble range for as long as possible, maybe easier on a Sunday morning or late at night or something that way you can take a look at the plugs and what the engine is doing at that rpm. Usually stumbling and such is a sign of a lean condition. Since it happens around the bottom end of the mid-range/top end of the low range, you are probably on the right track and maybe setting the needles a little richer will help and/or turn out the mixture screws a 1/4 turn or so. Try posting some pics of the plugs in the "stumble" range that was how I fixed a lean hole on my bike was by driving around that range and then taking a look at the plugs, it really helped. I just added a shim and it fixed it, as I remember it was right around where you're experiencing the issue(transition area between low to midrange). However I just had a weak spot I never had it stumble.
But driving around in that rpm range and then looking at my plugs really helped. What I did is cruise around the low point of the weak spot and then accelerated to the high point of the lean spot then deaccelerated and repeated a bunch of times. You are basically artificially creating a bunch of passes in the trouble range then cut the engine and coast to a stop, I'm sure that will really help you out. Fourtunately 3,000 to 4,500 rpm is right around the legal/quasi legal highway speed so if you go out at night with top gear you're putting alot of load on the engine which should colour up the plugs nicely. If the highways are busy 3rd gear should be around the 60 to 80 kms an hour mark which will be fine as well. I went to an industrial area after dark to test where it was totally dead by 7 at night so there was little traffic and a 60 km/h speed limit.
If the trouble area gets better when warm then cold then that area is too lean. I would try adding a shim or another notch with no shim and see if it clears up, After 4.5K the mainjet is really calling the shots and from the sound of it your spot on. Below 3K the pilots are calling most of the shots and you seem fine there as well.
-
Thanks a ton. That's exactly what I was hoping to see, a confirmation of my thoughts/process.
I'll update with my findings.
-
Tried many different settings today.
Went to 4th notch 1 shim as Dale Walker recommended....Same 3-5K bad stumble
Went to talk to a local guy that has a bike shop (and more motorcycle racing trophies than Ive ever seen in one place) He says this is a very common problem with the stage 2 holeshot kit. He recommends dynojet only for street bikes.
Anyway, He thinks I'll probably have to go back to the stock airbox to get it to go away completely.
On his suggestion I tried setting the fuel screws to 2.5 turns out. Not really any change.
Then changed to 3rd notch no shim as he recommended. The worst it's been...OK to 3K then bad stumble to 5K where it will NOT accelerate any further. I'm about a half inch away from buying new springs (the ones I had to cut) and putting it all back to stock.
-
Turning the screws in will make that lean area worse. Try 3.5 turns like you said and what was the best you got so far? Start there and maybe try one shim to richen that area. I know the stage 2 according to the dyno chart he has is a little flat in that area but it shouldn't be that flat. Just for fun set everything back to where you got it ok. Turn the mixture screws out to 4 temporarily and see if that helps a bit in that area. If so then you know that area is lean. I think you said it wasn't as bad with the 4th notch with no shim. So try that and turn the mixture screws out to 4 just to test if that area gets a little better. Turning out the mixture screws will add a bit to the overall mixture and anything under 1/4 throttle and help the transition area. That little half turn may "get you over the hump" by adding a touch more fuel in the lower range and a bit overall. It may ultimately be too much but if it's better than maybe try 3.75 if it too rich down low.
I only have a stage 1 and I'm at 3.5 turns out I could see a stage 2 with way more airflow needing a bit more on the pilots at least until the main jets fully kick in. Try the best you got with half a turn out on the pilots and see if it helps the bad area, ignore any low end richness temporarily if any. At least you'll know where you need to go. Does the area get a bit better when you don't open the throttle so much? Or worse?
Since the mechanic told you to go leaner and it got worse it only stands to reason you need to go richer. When you let off the gas and deaccelerate, do you get lots of popping? Thats a sure sign you need a bit more of the pilots.
-
This is right from Dynojet:
Pilot Jets:
"This controls 100% of the engine idle and 25% of the transition onto the needle. Dynojet has found that the engine will idle with the standard pilot jet, with or without the air-box and with the slides and needles removed from the carburetors; therefore we never change the pilot jet. Doing so is proof that you are not using the other circuits correctly. Idle and off idle is controlled by the mixture screws and the float level which have the most positive effect below 4000 R.P.M. On some models the pilot air jet is changed to provide optimum fuel economy. Correct balancing of the carburetors also ensures a smooth idle."
So try that half a turn out(3.5-->4 turns) and see if the transition is a little smoother. Easy to turn back if not.
Also if you put the stock springs back in there they are stiffer and the stumble will be worse as the slide and needle won't rise as much as what you already have making it leaner again. It just seems you have a little bit of a problem in the transition area. You could also try one size up mainjet if it can't be solved with what you have. Also next time you have the carbs off I would check float height. Mine were all over the place from the factory when I installed the stage 1. They are currently at the recommended 13mm. You measure from the base of the carb body to the highest point on the float. Best if you stand them upright on the side and then gently move the carbs until they fall into place and stop with no pressure. Check with Dale to see if the float height for your kit should be the stock 13mm or different, for example Dynojet kits want the float height set to 11.5! Wow thats rich, but they use different mains, needles, slide springs, etc.
-
How did you make out? I have a stage II on my 98 1200. I've had them out plenty of times trying to get them just right. Go under "CV Carb Tuning Procedures " in the dynojet site. Everything has to be done in the right order.
1st is the best main jet, I'm running 150s in mine,but I have run 147.5s. (I only noticed the 147.5s to be lean at full throttle coming onto the front and back straights at the tack,so I went back to the 150s)
2nd step is mid-range,full throttle/5-7 rpm (best needle clip position)
if it gets worse as it warms up=rich. Better when warmed up = lean. Equally well = properly set.(mine are on 2nd notch from top w/ Dales needles)
3rd low end (float heights) Run 2nd gear 2-3k rpm to full throttle without stumbling or missing.If you have a wet rhythmic soggy area and gets worse as it warms up,lower the fuel heights. If its dry,flat between 2-3K and gets better as it warms up, raise the fuel hieghts.(mine are at 14.7mm)
4th fuel screw settings,idle and low rpm cruise,if it gets better as it heats up, its lean.Better when cold=rich. Blipp the throttle, if it drops below the idle speed and then returns, its rich. If the rpm hangs up before returning to idle speed, its lean.
Hope this helps,Dan
-
PS. I started 3 turns out on the fuel mixture screws,but it tunned better at 2.75 turns out.
-
Dan has got some good advice. I'm sorry I only have a stage 1 so I can't really comment on the float height but I believe you said you might be unsure of how it's set? It might be worth the hour to check and see if it's set correctly. Stock and for stage 1 is 13mm. If the stage 2 requires a higher or lower fuel height I could see that causing some problems. Geez you guys, stage 1 is crazy enough! It must be totally crazy with a stage 2!
You guys must never miss the liquor store close time! :grin: In fact I think the track and drag strip times might improve if they had a liquor store about to close at the end of the track!
-
Dan has got some good advice. I'm sorry I only have a stage 1 so I can't really comment on the float height but I believe you said you might be unsure of how it's set? It might be worth the hour to check and see if it's set correctly. Stock and for stage 1 is 13mm. If the stage 2 requires a higher or lower fuel height I could see that causing some problems. Geez you guys, stage 1 is crazy enough! It must be totally crazy with a stage 2!
You guys must never miss the liquor store close time! :grin: In fact I think the track and drag strip times might improve if they had a liquor store about to close at the end of the track!
We happen to have a tapped keg and plenty of booze at my buddy's bike shop :beers:.
I had to have someone help me do the float heights, my glasses aren't strong enough to tell when the needle was compressing or not. I think may float height could be tweaked just a little more,but its close enough for now. Seems like its just a little rich @ 3-3500.
-
Going to try and hit it this weekend. Thanks Guys!!
-
I know it's been a while, Been a lot of things tried. Many different seting and I finally gave up and put it back to stock....even ordered the stock size springs to go back in the top of the carbs. Got it all back together yesterday. STILL RUNS LIKE CRAP. Won't take over 1/4th throttle and won't even make it over 4K no matter how slowly you rev it.
Obviously I have bigger problems causing my stage 2 kit to run bad. UGH...Not sure where to go from here....Full Carb Rebuild?
-
How do the plugs look? Is it completely back to stock? Ie. 15 pilots turned to 3 turns out. 100 main jets with no shims. Completely closed airbox with snorkle with stock OEM filter? Stock slide springs? 5 degree timing advancer OFF? It might actually be worth it to take to a shop with a dynometer and get them to tune it. THere is a shop in Toronto that for $300 will dynotune a carbbie bike with unlimited dyno pulls and tuning until the bike is perfect. Do you have such a shop in your city? It might be worth the few hundred bucks to have it running perfectly with the stage 2 I imagine in the states would be slightly cheaper. A dyno run with a fuel/air map and someone tuning it would be foolproof as the dyno and A/F mixture ratios don't lie. If you're using the 17.5's as pilots it will be 1 1/2 turns lower than the equivilent on the 15's. Ie 3.5 turns on the 15's are only 2 turns on the 17.5's. THe same shop does 3 pulls for 50 bucks with printout if you know how to read the fueling or just post it here so we can have a look.
Maybe a stage 1 would be better. Its less of a change from a full blown stage 2 but still gives most of the stage 2 power without being as finicky to temperature/humidity changes. Since you already bought the stuff from Holeshot to go to a stage 1 you would just need $8 in jets and go with 110 mains and 15 pilots out to 3.75 turns and a 1.5" hole in the top of the airbox cover and stock filter. You already have the advancer.
The only other thing I can think of is maybe the 5 degree advancer is too much for your specific bike. I've read a guy who did a stage 1, etc ,etc and it was great however when he put on the 5 degree advancer it ran like crap and could barely idle. There was just something about his bike that hated the extra timing advance. Who knows maybe in the factory the timing plate was drilled slightly larger with the holes and had some more advance than other bikes, his coils were unusually good, etc ,etc. Who knows really but he took the advancer off and it was wheelie city. Since taking off the advancer only takes 15 min it might be worth putting the bike completely to stock then starting one step at a time until it starts coming around. If you lean your bike to the left on the kick stand you don't even have to drain the oil. Just put a tinfoil pan underneath the timing signal cover to catch any drips.
I think maybe there was too many drastic steps on the bike than it could take at one time and most of the time on these kits its fine however every bike is different so starting from stock and working up one at a time is a good idea. Here is the stock and other settings for reference in case you need the info:
GEN2/GEN3
Float height 13mm for all
Totally stock:
----------------------------------------------------------------------------
Shit stock exhaust
Totally enclosed airbox with stock filter
100 mainjets
15 pilots jets with 3 turns out on mixture screws
Slightly modified for a slip on:(My friends runs great like this)
-----------------------------------------------------------------------------
Aftermarket slip on, ie holeshot, muzzy, yoshimura, etc ,etc,
102.5 Mainjets
1 Radioshack shim .020 or about 2 of the Holeshot shims
15 pilots to 3 - 3.5 turns out(can't remember think it was 3.25)
Stock airbox with snorkle and stock filter(no extra holes in airbox)
Stage 1:
----------------------------------------------------------------------------
Aftermarket slip on, ie holeshot, blah blah
110 Mainjets
2 Radioshack shims or 4 or 5 Holeshot shims
15 Pilots at 3.75 turns out
Stock airbox with snorkle and a 1.5" hole cut into the top
With these baseline settings it should get your pretty close. Since you already have most of the good components of the holeshot kit, ie adjustable needles, etc. It will probably be actually easier to go up a step at a time. If you still have the slip-on on there with the stock settings it will be weird past 1/4 throttle because of the fact that the stock jetting is already lean as hell and making the bike flow better only aggravates it even more. Since you have the good Holeshot needles are you using them? If so where is the C-clip set to? I imagine if you used the Holeshot needles you probably set them to the middle or neutral position. Anything over 1/4 throttle to 3/4 of a throttle is adjusted by the needle. Even with the stock jets, the bike might run better if you richen up the needle a notch by putting the c-clip down a notch or two. That and maybe turn the mixture screws out a 1/4 turn to 3.25 might do the trick for now. Since this is a small step you will be able to feel the improvement right away.
Although looking again at your symptoms it seems like you have a fuel starvation problem. Have you tried running the bike on prime? When you ride around for a bit, pop the gas cap off. Do you hear a whoosh?? You could try running with the gas cap loose to see if you have the breather hole grundged up. Carbs very very very rarely just stop functioning. Even crazily out of tune, they should work sufficiently to run the engine through the rpm ranges. Try the petcock first as that is usually the culprit with fuel feeding problems, either too much or too little fuel.
If you wanted to try this as well. Run the bike till its warm and take off the tank. Attach a funnel to the fuel line and plug the vacuum tube that goes to the #4 carb with a screwdriver bit or a piece of tape. Have a little bottle of fuel so you can sort of top up the funnel with fuel so you can run the bike without the tank off it. Does the bike run better?(don't drive it just rev it) Does it suddenly have a more snappier throttle? If so the petcock might be wonky. While the tank is off, does the spigot leak when the bike is on "ON" or "RESERVE"? Does the fuel flow freely when set to "PRIME"? It could be that the diaphram is dead on the petcock or gummy and the vacuum from the bike running only can move it so far to provide a limited amount of fuel.
-
i read this discussion, and i feel the same: it's NOT possible to have a 2nd gen B12 well tuned with any kit.
simply under 3k the bike has a stumble. it has it in any possible configuration of jets, needles-shim and slow jet.
i have tested all the possible combinations found that the best is keeping the 15 slow jet, 147,5 main, and 4th notch from top on the needles.
On this configuration the bike work well up to 3 K, but it ALWAYS stumbles off ildle.
This stumble is not possible to remove in any way, in any configuration.
it's 2 years that i drive the bike in that condition, and also i contact dale, but no result.
I'm thinking to come back as OEM.
-
Well you could go back to stage 1 which is way more drivable and keep %70 of the horsepower gains.
-
the stage 1 has only larger main jets (110-115 if i remember), it keeps the oem needles ?
-
Yeah, I'm at 3.75 turns out on 15 pilots and have a 112.5 mainjet. You might be totally fine with a 110 mainjet but I needed a little more juice. I think it's slightly rich, but it's better than slightly lean on the 110's. You cut a 1.5" hole in the airbox and use 5 shims on the needles. Do you still have the nice adjustable needles? You can probably use those. You should get around 112-114 HP instead of 117-119 HP, so you're only losing 3-5 HP and you get better gas mileage, and better drive ability. It's the easiest to live with of all the mods. YOu use the stock filter. If you wanted to use a K&N filter you have to go to 115 or 117.5's. Octane is going to do it this summer so I'll know if hes good as I have a K&N filter. SHould give another couple of ponies up top.
-
i got the adjustable needles.. but i think they are the problem.
the shape is really different respect to the oem. they are much more conical, the oem are more similar to a cylinder, the conicity is low.
the oem also have the white plastic under the "circlip", this cause the little spring above to be better compressed, and the oem needle just look to be more stable, when you install it, it looks "maded" for it.
The aftermarket needle moves too much and looks really not made for this carbs. This is what i think.
In my life i rebuild a lot of carbs, and normally the needle is firmly positioned, and if you want to move it you must press it with a certain grade of decision, the aftermarket needle of my B12 looks loosen.
I was searching on this forum people that mounts the stage2 holeshot on a 2003 B12, for understand if this is normal but i found no people that gave me precise indications.
I found only lot of problems.
I think the gen 2 carbs are worst that gen 1.
So, this is what i do:
I cut the diaphram spring by 25mm, keeping the cuitted part upside
I install the new holeshot needles (4th groove from top with shim)
i istall the slow jet 17,5, (but the bike was rich as hell, so i come back to 15 at 3,5 turns out)
i install 147,5 main
I put pod filter
i check float bowls (i got the specific gauge)
I remove plastic tube between 1-2 and 3-4 carb
i try all combinations between screw and needle position, but now i'm tired to have my bike 90% of time spreaded around my garage. I want to drive it.
-
i feel the same: it's NOT possible to have a 2nd gen B12 well tuned with any kit.
simply under 3k the bike has a stumble. it has it in any possible configuration of jets, needles-shim and slow jet......This stumble is not possible to remove in any way, in any configuration.
My 2nd Generation B12 is very well tuned and all I did was follow Dale's instructions exactly with no deviation and no shortcuts.
It pulls smoothly from idle on up with no stumble of any kind.
There is truth in the old saying that "Too many cooks spoil the broth".
I would just call Dale again and do what he says.
We live at just 11 feet above sea level so Dale's baseline settings will be very close to spot-on.
-
i do the same, i follow exactly the instructions.
sorry but for me the big mistake is cutting the carburetor spring.
the carburetor is designed to open diaphram with a certain vaacum, but especially the spring is designed to work ALIGNED.
If you cut it, also if you put bottom side the cutted part the spring works not well, it bends and stretch a bit.
What happens in my bike is that: with the 17,5 slow jet you are so rich at ildle, just you release the clutch for a normal slow takeoff the diaphram opens a little too much, causing the engine to go from "so rich" to "much lean" conditions.
..
For remove the off ildle stumble i need the 27,5 slow jet (!!!!!) but with a fuel level of 15,5mm.
Now i'm so rich at ildle but the bike works smooth.
I buy a set of new spring from suzuki dealer and i found the bike working SO WELL. especially at midrange. Keeped the 27,5 but with only one fuel screw turn out.
Now problem solved.
But this second one is a factory pro stage 3... sorry. With the holeshot i was never able to obtain a decent result. Maybe my bike is "borderline" and much different from others due to a tolerance chain ??