Bandit Alley
MODEL SPECIFIC => SUZUKI BANDIT 250 & 400 => Topic started by: tomacGTi on June 28, 2007, 09:53:28 PM
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So now that most of you have heard of what happens when you mis-time some cams and disaster strikes. A new-to-me engine and a month later, I have a Bandit again.
I was originally looking for a new head but once again, ebay saved the day with an 11k motor and a shot set of carbs. The shipping was more expensive than the engine itself and arrived yesterday so with some help from the little lady, I got to work (no we didn't do the swap in the kitchen but she did help me hoist it into the frame).
This time around I was unbelievably anally retentive in the cam installation. I should have just left the stock cams in the motor just to make sure the damn thing worked but I decided to just turn it over by hand as many times necessary to make sure everything cleared sufficiently. Plus I needed to beat the thing that originally beat me. Some anal-retentive hints on cam installs:
-Disregard the markings at the end of the cams and match up the cam wheels/pin count. E/1 flush with the head and 20 pins to the "2" on the intake. Doing this will make the marks on the ends of the cams not match but those only matter when you're setting lash. That's it. Also, don't be alarmed by the excessive amount of slack in the chain inbetween the cams. The adjuster will take it up (manual or otherwise). The other good part: you now only need one feeler guage to set lash: .005".
-The cam sprockets are the same for both intake and exhaust, just positioned differently. Same part number and all, make sure you have some loctite on hand when you spin the bolts off.
I originally had set everything up using the end marks on the cam and that was my demise. The exhaust cam had enough clearance but the intake cam following behind didn't and met Mr Pistons.
-Make sure you turn the motor over by hand until you are sure that Mr Piston is not about to smack Mr Valve. I must have dry-spun the motor 50 times honestly, I was that nervous. When I had placed the cams in using the end marks, it was obvious that there was some resistance which made me rethink and go back to the manual again.
-Things are going to sound a bit different. The cam will make the motor sound different, a bit deeper and more sharp. It didn't sound like the same bike. I had also modified the collector in the headers with the thought that it was opening things up by removing the silencer. There is now a straight shot from the header tubes into the 2-1 splitter into the midpipe. Call it the poor man's header.
-Midrange is where the swap shines. That dead spot at 6-7k before you hit the mains? Gone. Mid-throttle roll-on just has acceleration now till you get to 3/4-full throttle. It's nice and fat and you can roll onto it as early as 4-5k if you wanted to.
For reference sake:
-3.5 turns out
-105 MJ (Mikuni) Dynojet needles
-middle needle position with one shim
-modified airbox using a different snorkel
I think I may be fat on the mains, but we'll see. I'll get some miles on it and check the plugs (new) for some color.
Now, the downsides or, "not everything is a bed of roses".
-Jury is still out on valve to piston contact in the upper ranges. Maybe its me but when I brought it up above 10k, it had the same sound as when it broke on me a month ago. Maybe I'm paranoid, but time will tell. Jay did you rev out beyond that when you did this with no ill effects?
The tone that the motor makes is even different. Very vtec like once above 10k. You can hear it from the headers right on out the back of the bike.
-Idle is really low for some reason. The cam overlap at low revs is probably so much that there is a huge wave blowing back through the carbs reeking havok on the CV slide. I had it set at 1200 and anything more than that would cause the rev to hang up around 2k and then come very slowly back down. Backing the screws out another 1/2 turn helped but not by much. It did die out on me a couple of times but whatcha gunna do?
-It's LOUD. The bike isn't nearly as quiet as it used to be. It really is like a different bike the way the power delivery has changed. This is regardless of the collector mod or not, the cams have changed the breathing of the motor.
-If you F it all up, a motor weighs in the range of 150 lbs or so. Start lifiting weights, saying your prayers and taking your vitamins Hulkamaniac because it's cumbersome as hell to work with.
-Re-jetting. Yes it sucks and I'm not looking forward to it either. That and having to relearn the damn bike. Yet another thing.
So there you have it. Just in case you want to take this on yourself, there's something to refer back to. I can't stress it enough to be anal about the cam timing, it cost me nearly $300 once it was said and done. Don't make the same boneheaded mistakes I did. I'll report back with some ride impressions as I get some miles on the new setup.
-Randy
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At least you were able to source another motor and get back on the road. :congrats:
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mine revved to 14+ fine , but worth it to look down the bore with a flash light just bump the starter w/ all plugs out till the piston you want to look at is close to the bottom and you should be able to see if it has marks. just take it easy till you feel confident it what you done. always good to do a compression check to.
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Alright, so now a ride report. This is all with the butt-dyno, one of these days I'll get to a real dyno to suss it out.
-Bike has much more midrange than it did prior, there isn't as much of a midrange flatspot anymore at 6-7k. 8k is a whole different animal as the bike has a bit more urgency than it used to. It basically flies into the upper ranges and max power feels as though to be around 10-12k leaving some room for over-rev on shifts.
-Has a bit more vibration than it used to through the bars/bike. I'll resynch the carbs when I change out the oil at 150miles just to see. It synch'd out pretty damn even with my manometer when first put together.
-idle is a little tricky so I just sucked it up and set it so it comes down to 1400 when it's warmed up smoothly. Any more idle screw and it hangs around 2k way to much. Once again, I think this is because of the extra overlap that may have been introduced. I don't have degree wheels or slotted sprockets so I can't dial it out.
-This will change the sound of your bike. It is going to sound more shrill and has a growl at 8k+ that surprised the hell out of me. The airbox absolutely screams now at those revs with induction noise.
-I would advise to adjust your cam chain tensioner (if you have a manual one) when the bike is hot and oil has circulated. I adjusted it cold and it endt up being a bit too tight.
In all, it's a damn neat mod that should tide the HP bug in me over for a little while longer. Out of corners in the same gear as before, it leaps out and has a bit more punch. I know why Jay said that he had to re-gear and rejet after this mod. Of course he's no longer running it so maybe it isn't the cat's meow but for those of us without access to GSXR cams, it's not a bad compromise.
Here's the mod list for the jetting database.
-1991 bike
-At sea level, tested at around 75-80*f
-Modified airbox with no holes but a larger homemade snorkle, stock airfilter
-CBR thermostat (if you don't change this, you're chasing your tail jetting)
-3.5 turns out on the screws
-Dynojet needles, stock spring, 3rd clip with 1 washer
-stock float height
-stock pilots
-105MJ (Mikuni)
-factory headers with removed silencer from collector/Cobra F1S exhaust
-Pingel Fuel valve
Might be a bit rich on the main but pulls well, still have to check plugs to be sure but it should be close. Great midrange punch and low end is ok. It's probably close to the same just outshined by the stronger mid-high end from the cam.
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no im running the same brother just had to take it out to clear up some issues i thought where the cause but i don't write things down like i should.
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How did you put them in, from which mark to which mark did you count the pins of the chain? Sounds really interesting, since I'm mostly between 10000 RPM and the rev limiter anyway :bomb:
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just like stock just swap the for the intake cam you be looking at the same mark as if it where stock just have to set valve lash to the intake spec
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Tod, make sure you install them using the sprockets as your guide and not the marking at the end of the camshafts.
That was my very, very large mistake that cost me my old top end. Everything spec's out to the sprockets. and you only need one feeler now to adjust for lash.
-Randy
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Cool. If I have time I'll do it next friday, gotta do some other work too as I'm going on vacation. I never look at the markings on the side, lol I took the cams in and out about 6 times when I changed the engine a while ago because it only idled and blew back through the carbs when I touched the throttle... eventually the starter clutch, with the timing plate, was put on by the previous owner without the key :annoy:
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tomac how it coming? do you like it ? herrtod has done it and doesn't care for it id like to hear some more opinions maybe you guys can chat about it , I seemed to like it and was going to go back to it. He says that it seems to have a power loss from 12500 on.
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I haven't gotten out much mainly because of work and it being busy. I got out today for a little bit, here's another thought/impression.
LIke I said, the mid (6-9k) is definately better with the exhaust cam setup versus stock. That's where I spend the abundance of my time so I notice it more coming out of corners and setting up for the next. I don't think it's less power than stock, just different in the way it delivers it. I actually have found myself having to relearn alot of the corners just because of how different the power delivery has become. Since there's more mid, I can keep level throttle versus downshifting and balancing the throttle between engine braking and neutral/throttle.
It really feels like where I was rowing through the gears previously, I can hold a gear longer because I can let the revs come down further (since there's power there now) and still have room to spare up top. It isn't as frantic up top as it was prior but like I said, I think it's because it gets there with more urgency. Looking at some old dyno sheets from the board etc, it looks as though power tapers off at 11k even with the stock cams so for me 14k is more of a novelty since there isn't much after 11. Even when stock, the only time I would bang the limiter was on downshifts or just trying to pass a car and being inbetween gears, YRMV.
Most of the backroads around here are 3rd gear affairs rolling in and out of the throttle 35-70mph (50-110k or so) so that elastic powerband from 6k to 12k is really what works for me, the upper end is more insurance than anything.
Do I like it? Yes, because of the way I ride. It could also be my setup as well since all of my jetting is with 32mm carbs, etc.
-Randy
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thanks , I beleive it's all in what you like. cheers
Jay
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I don't like it at all. Idle is crap, flatspot at 6000 has gotten very bad but could be fixed by lowering the needles. No power after 13000, I used to hit the rev limiter in 2nd gear very easy but now it takes noticably longer. Strange thing is it starts to rattle at 10000 RPM and above. Everything is timed right though.
I'm putting in the exhaust cam again as soon as I have time. Hopefully the rattling will be gone, otherwise something went wrong... oh well I have a spare engine around already :roll:
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cool thats what this board is about opinion good to hear them.
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. Strange thing is it starts to rattle at 10000 RPM and above. Everything is timed right though.
:roll:
I'm not the only one then. Strange because I only notice it in the lower gears, 4-5-6 I don't, as much anyway. Is it the same for you, you can hear it from the right hand side in particular?
Tod, I guess I guessed the jetting right for the bike because it all was better for me. The idle is a little wonky but once the bike is warm, it's sitting right at 1200.
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Idle is crap because it's too lean, I'm running a 30 pilot jet, which was correct with the exhaust cam in. The rattling is quite loud and seems to come from everywhere :shock:
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now tomac when you put your intake in the exhaust you removed the sprocket and and put it back on like it was the exhaust right sorta facing the same direction as if it where the exhaust?
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Yep, double checked against the other exhaust cam as well. Everything this time around is set up by the book. I've been trying to wrap my head around this rattle/induction noise thing for a little bit now. Jay, are you getting this sort of thing as well? Like I said, in higher loads it isn't as apparant but down low it's more the case.
The last time I experienced something that sounded close to that was on my VW 16v when the cam timing was over-advanced to the point where you could hear the valves just about knicking themselves. Obviously on a larger scale but similar.
30 pilots, holy shit! Explains why I'm at 3.5 turns out or so. With the 17.5p, stock float height and 105MJ it's idling fine when warm albeit a bit recalcitrant sometimes.
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i had something going on but i couldn't put a finger on it as i had slot cam sprockets and was messing about with the cam timing but i ended up racing it any way and felt a difference but i had a bunch of issues like i was speed restricted in the top two gears and was fighting that. but i took that out cause it kept blowing head gaskets from the surface not being perfectly machined then I timed my cam wrong and broke a valve and that is where it sits now but was going to continue with the research with the cams as the one time i raced i had liked it . All i can say is keep an eye on it and if you have a problem id be truly sorry and donate some parts to the cause. But you all have to understand that i groove , cut, pocket , mill, deck , slot whatever it takes ive done almost all but i keep terrible notes and may be fuzzy on some of the things ive done lol thats why i keep spares and i understand that most cant afford or have the knowledge to be able to work on there own bike so its good you 2 can wrench on things. If you had a bore scope or if your local auto zone rented one id say look in the bore for the exhaust touching the pistons and thats the only thing i can think of i have a set of stock pistons cut 10 thou on the pockets that im not using but i can remember why i cut them could be one of 3 things ive milled 10 off my head , 10 off my cylinder or because of the cam swap. one thing i can say for sure is ive taken 10 off the cylinder and ran all stock with no problems so make your own judgments on that one. with my big bore since i had to mill the cylinder again because of the indentation i had made on the cylinder laying other parts on it while it was on a shelf im currently running 10 off head 10 off cylinder big bore kit with 2 base gaskets.
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Thing is though, the cams are theoretically asymmetrical so all things considered, it should be fine. Even eyeballing the cams themselves, they're pretty much identical, just a slight bit more lift. Ideally yes they should be timed to one another and run on a dyno to see what's effective but I don't have the time and money to invest in something like that.
I have something done similar to the intake cam of my VW where I use a modified exhaust cam as the intake. Timing unmodified and just dropped in, it worked fine all the way to the 7200rev cutoff but when the sprocket was brought in to smooth the overlap, the cam became mush smoother though the top end hit wasn't as pronounced.
The only thing I can think of is that the lift may be too great for the rockers (since the exhaust rockers are different: thicker versus the intake) and at certain RPMs may be floating. Could even be coil bind at those revs due to the rockers/lift/speed (I haven't the time nore the machine to check springs). Something to compare to existing camset #'s out there to see if that could be the case.
I wish I knew someone with a boroscope because that would answere alot of questions quickly. Since everything is so damn small, it's almost impossible to peer down the plug hole down the piston to see if there has been contact but I also believe if they've been touching, something should have let go by now. I mean, the plugs even look fine.
There are lots of variables in what can be causing the "rattle" and I think that it could even the be the cam chain as well. Things turn over fine by hand and I have run the thing to 14ks with no real ill effects. All the marks line up and it fires up as if it were stock so I really don't know. It's going to have to wait till I get a couple of more miles on it and peel off the VC and check tolerances etc.
The joys of experimenting and tuning. Like I said before, I'm happy with it as it's made the bike more rideable for me but what works for some won't work for others.
If you have a chance to get over to SVRider, this is apparantly a pretty hot-shit mod for them and they even use cams across generations looking for the correct lift and overlap. Interesting reading there. They've got dyno plots to prove it and like anything, without changing displacement, all you're doing is idealizing what you have and you'll lose/gain in different places, moving the powerband around.
One also has to remember that the stock cams are what Suzuki thinks is the most ideal for the broadest range of what the bike will be used for. It may be tame but it's the most consistant. Anything else outside of the prescribed box has to comprimise something.
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very true all all accounts and the sv guys and some other racers is where i got the idea of the cam ordeal they do it on gsxr 600-1000's to. Your story about the VW reminded me, I have read a article about a 90+ hp fzr400 that found the best set up for them was 2 exhaust cams now i have not tried this one but someday i might. And like you i have not the time or the money to run to the dyno every time i try something new. I put it to the track and check my times and try to keep as many variables the same but like i said some times its hard when you don't take good notes. (Gary lol) But on another note the rocker arms at-least in my parts book are the same part number. here is another note for you rocker arms big beefy mothers they are i learned something along time ago when i started off tuning single cylinder bikes with rocker arms if you take the casting marks off and polish them up you rev quicker believe it or not, I do it to anything with rockers now.
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I'm going to put the exhaust cam back in tomorrow. I've done some riding (about 500 km's), had it in the rev limiter a lot of times but it really lacks power up there. I don't care much about anything below 10000 RPM, only when commuting. I could try to rejet the carbs to make it run right and do some more testing, if it wasn't for the rattling.
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Tod, that's the thing that I've found for this mod, since I spend most of my time between 8 and 12k+ it works well for me. It certainly isn't a drop-in mod because of the jetting changes but if we can standardize what we've done, it may make it easier.
It really improved the midrange so whatever little torque curve the bike has is more rideable. I'd really like to try a set of GSXR cams to compare this setup to but I really don't want to spend more money when I need to start saving for tires later this year. Sounds like to me that may be the better setup for you since you spend most of your days north on the tacho. Here's the other thing: do you have a V? Maybe that's the big difference?
Jay, of the rockers you sent me, it was obvious that there were two distinct ones. Now I don't know if the GSXR is different but the exhaust rocker is slightly "chunkier" than the intake rocker. They're also two different numbers in Bike Bandit.
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Jay, of the rockers you sent me, it was obvious that there were two distinct ones. Now I don't know if the GSXR is different but the exhaust rocker is slightly "chunkier" than the intake rocker. They're also two different numbers in Bike Bandit.
well now thats interesting because i mostly go by my parts book for the gk73a i have #12840-32c00 for a both i may have to look at my motor a bit more closely now and see if i have swapped some parts.
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I'll get pics for you Jay as I still have those rockers you sent me. They're distinctly different between the two.
I think I may be wrong on the PN thing as well but like I said, they're obviously different. Perhaps 93 versus other years?
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OK well if the b4 has 2 part numbers then that may explain it as i have a ton of b4 and 73 motor parts but i also have some 71f stuff mixed in. So if they have two different rockers id use the lightest ones im sure i weighed mine after i polished them and they where all within a gram. And yes pics are worth a million words. cheers
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I don't have a VV model. Mine is a '92, with a '94 engine with the '92 cams and ignition stuff, Yosh system with a Micron end can, K&N replacement filter and Factory Pro ti needles. GSXR cams are the same as my '92 B4 cams, I have both and some others as well.
I've got the stock exhaust cam back in. It's back to life :bandit: More power everywhere, airbox and exhaust sound is back. With the intake cam it sounded rather tame. Oh i love the sound of that rev limiter coming up fast in 1st 2nd 3rd and 4th gear. Creepy thing was, I broke 3 bolts holding the cam, I didn't over tighten them when installing. Strange...
I have my hopes put on the GSXR CDI I'm receiving soon from Japan, I need more revs before the limiter kicks in, especially in 2nd gear corners where I just can't go faster because of the limiter. If I take them in 3rd gear I'll be a bit slower. I'm running a 14-43 final transmission (RGV 250 rear wheel) which I quite like, gives more speed in lower gears and even in 6th gear it has a higher top speed.
What's to gain by slotting the cam sprockets and advancing the ignition a bit?
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What's to gain by slotting the cam sprockets and advancing the ignition a bit?
equal lobe centers , messing with where the power comes on falls off adjusting the powerband as for the slotting of the pic up more hp
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so what harness you running the 2 wire or 3 wire cdi one
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How about a UPDATE brother all running good still ? about how many miles?
cheers
jay
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Bike is still running well with the cam in with the exception of some motor issues. Probably close to 3500 miles on it now.
Very strong and still has great punch despite the motor having a smoking issue. I think a re-ring will be in order as it's the same issue as when Coopz had his Bandit (full-on mosquito patrol). It's getting a bit worse so this winter the motor's coming out again and it's getting freshened up.
I ride with a bunch of guys from the Monster forums and have no trouble keeping up or even going head-to-head down the street. Most ride S2Rs so the little Bandito can hang with the literbikes just fine. When I first went out with them, it was definately running out of steam but now certainly not the case.
-Randy
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hows it coming with the smoking
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Waiting on stem seals from APE and the in-bike valve spring compressor is built and waiting to be used.
Works just fine with a head on the bench so in theory it should work in the bike as well.
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So now that most of you have heard of what happens when you mis-time some cams and disaster strikes. A new-to-me engine and a month later, I have a Bandit again.
I was originally looking for a new head but once again, ebay saved the day with an 11k motor and a shot set of carbs. The shipping was more expensive than the engine itself and arrived yesterday so with some help from the little lady, I got to work (no we didn't do the swap in the kitchen but she did help me hoist it into the frame).
This time around I was unbelievably anally retentive in the cam installation. I should have just left the stock cams in the motor just to make sure the damn thing worked but I decided to just turn it over by hand as many times necessary to make sure everything cleared sufficiently. Plus I needed to beat the thing that originally beat me. Some anal-retentive hints on cam installs:
-Disregard the markings at the end of the cams and match up the cam wheels/pin count. E/1 flush with the head and 20 pins to the "2" on the intake. Doing this will make the marks on the ends of the cams not match but those only matter when you're setting lash. That's it. Also, don't be alarmed by the excessive amount of slack in the chain inbetween the cams. The adjuster will take it up (manual or otherwise). The other good part: you now only need one feeler guage to set lash: .005".
-The cam sprockets are the same for both intake and exhaust, just positioned differently. Same part number and all, make sure you have some loctite on hand when you spin the bolts off.
I originally had set everything up using the end marks on the cam and that was my demise. The exhaust cam had enough clearance but the intake cam following behind didn't and met Mr Pistons.
-Make sure you turn the motor over by hand until you are sure that Mr Piston is not about to smack Mr Valve. I must have dry-spun the motor 50 times honestly, I was that nervous. When I had placed the cams in using the end marks, it was obvious that there was some resistance which made me rethink and go back to the manual again.
-Things are going to sound a bit different. The cam will make the motor sound different, a bit deeper and more sharp. It didn't sound like the same bike. I had also modified the collector in the headers with the thought that it was opening things up by removing the silencer. There is now a straight shot from the header tubes into the 2-1 splitter into the midpipe. Call it the poor man's header.
-Midrange is where the swap shines. That dead spot at 6-7k before you hit the mains? Gone. Mid-throttle roll-on just has acceleration now till you get to 3/4-full throttle. It's nice and fat and you can roll onto it as early as 4-5k if you wanted to.
For reference sake:
-3.5 turns out
-105 MJ (Mikuni) Dynojet needles
-middle needle position with one shim
-modified airbox using a different snorkel
I think I may be fat on the mains, but we'll see. I'll get some miles on it and check the plugs (new) for some color.
Now, the downsides or, "not everything is a bed of roses".
-Jury is still out on valve to piston contact in the upper ranges. Maybe its me but when I brought it up above 10k, it had the same sound as when it broke on me a month ago. Maybe I'm paranoid, but time will tell. Jay did you rev out beyond that when you did this with no ill effects?
The tone that the motor makes is even different. Very vtec like once above 10k. You can hear it from the headers right on out the back of the bike.
-Idle is really low for some reason. The cam overlap at low revs is probably so much that there is a huge wave blowing back through the carbs reeking havok on the CV slide. I had it set at 1200 and anything more than that would cause the rev to hang up around 2k and then come very slowly back down. Backing the screws out another 1/2 turn helped but not by much. It did die out on me a couple of times but whatcha gunna do?
-It's LOUD. The bike isn't nearly as quiet as it used to be. It really is like a different bike the way the power delivery has changed. This is regardless of the collector mod or not, the cams have changed the breathing of the motor.
-If you F it all up, a motor weighs in the range of 150 lbs or so. Start lifiting weights, saying your prayers and taking your vitamins Hulkamaniac because it's cumbersome as hell to work with.
-Re-jetting. Yes it sucks and I'm not looking forward to it either. That and having to relearn the damn bike. Yet another thing.
So there you have it. Just in case you want to take this on yourself, there's something to refer back to. I can't stress it enough to be anal about the cam timing, it cost me nearly $300 once it was said and done. Don't make the same boneheaded mistakes I did. I'll report back with some ride impressions as I get some miles on the new setup.
-Randy
Well done, very impressive home tuning :clap: love to hear of people doing this type of work. would it be worth fitting a shim under the block if you are worried about valve to piston contact? or would losing a little compression be more of a problem?
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Well done, very impressive home tuning :clap: love to hear of people doing this type of work. would it be worth fitting a shim under the block if you are worried about valve to piston contact? or would losing a little compression be more of a problem?
:eek2: WOW! Suki, you sure are learning fast!
...or is your BF posting as you? :bandit:
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Well done, very impressive home tuning :clap: love to hear of people doing this type of work. would it be worth fitting a shim under the block if you are worried about valve to piston contact? or would losing a little compression be more of a problem?
:eek2: WOW! Suki, you sure are learning fast!
...or is your BF posting as you? :bandit:
no, I told him about the cam swap and he told me that though... :lol:
he said he might join up, he has 3 oil cooled 1100's but no bandits
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No, because then you would alter the compression ratio and that would literally change everything.
I've run it pretty damn hard into the limiter and nothing has gone boom so I think it's just a byproduct of the cam's different profile. I'll check it one last time when I have everything apart but I think that it's just inherant of the mod itself (the noise).