Hello all, first post here. I picked up a 1978 Suzuki GS550 not too long ago to start a cafe racer project. When I got it, it ran alright and got me home, but it has been short on fuel at high RPM's for as long as I can tell. I cleaned the carbs and everything, verified I'm delivering enough fuel to the carbs, throttle moves the needle fine and when I get to that RPM range I can pull the choke on and it'll stop the stuttering and climb over it. I don't have a carb sync so all I can think of is it being a tuning issue. If anyone could tell me if I should or shouldn't invest in a carb sync to see if that solves the problem or if it's something else it would be much appreciated as I am out of other ideas.
Cuts out at 6500 RPM on GS550
- Thread starter Boomer21
- Start date
Sounds like you have an air leak in one or more of the manifolds. The bike is sucking air at higher RPM's and starving for fuel. That's why pulling the choke helps it get over it.
Make sure all the bolts and clamps are tight. If that doesn't fix it. With the bike idling, take a can of carb cleaner and spray each manifold in short bursts. Try and get all the way around each one. If you hear any change in the idle RPM while doing this... that's where your leak is.
Make sure all the bolts and clamps are tight. If that doesn't fix it. With the bike idling, take a can of carb cleaner and spray each manifold in short bursts. Try and get all the way around each one. If you hear any change in the idle RPM while doing this... that's where your leak is.
IAMBLAMB
Been Around the Block
I just picked up a GS550 as well and know I'm going to have to rebuild the carbs, which is OK with me. I might pm you at some point to ask questions about your bike since its supposed to be roughly the same thing ( only a few years off of mine.) This is going to be a total noob question and I'm ok with that because, like I said, this is my first bike ever. Where is the petcock on this thing. A picture or diagram or pretty much anything would be fine. But the bike isn't wanting to start and I think that's why.
What year is it? The guy I bought mine from gave me an extra set of carbs, not sure of the condition because the set on there is rebuilt to factory specs. But if it's an 80's bike the carb setup could be way different (internally). I adjusted one of my points yesterday and it climbed over that spot in the RPM range, then it started raining. I'm going to adjust them both a little finer today and see what I get. I did also notice that two of the clamps (the two on the inner cylinders, on air box side) are missing from the carb. Going to get clamps on there today as well and probably polish some more of the aluminum on it when I get home. Thanks for that carb cleaner idea, I'll definitely be giving that a try.
Yeah I know a guy through a string of other people with an 83 and apparently his is set up much different. If yours won't start try checking the gap on the points and functioning of the choke (of coarse verify fuel and spark first) but the points were messed with quite a bit on mine.
So I sprayed carb cleaner at the carb inlets and outlets and found a small leak that would only open up at higher RPM, and also adjusted both points to .015 yesterday. Took her out for a spin after fixing the two and it ran like new. Thanks for all your help, and I'll have to start a build thread on here or something when I get to the interesting parts.
Going for a cafe look. No front faring or anything, just a home made seat, some clip ons and a paint job. Been polishing everything aluminum on the bike and just restoring it so nothing too exciting yet, but my clip ons got here today! Ill work on it all day tomorrow and post some pictures of what I'm working with, it's only got 13000 miles on it and it ran (just not well) when I bought it. So it's more aesthetically challenged than anything.
i did my own research on that because it made no sense when i read it. Now it doesSonreir said:
i have personally experienced higher RPM stalling that was traced back to vacuum leaks and cured accordingly. I now can only guess that since N/A engines generally lean out at higher RPM's, the extra air added by the leak must amplify the lean condition, causing the stalling symptom.