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My 1993 Katana 750 is driving me nuts.

The bike orginally had dirty carbs, would idle down slowly until it died. I cleaned out the carbs and in doing so learned that in addition to being dirty, some else had previously rebuilt them and put the wrong size O-rings on half the floats. I replaced all these, carefully cleaned out everything I could, made sure every float was clean and sitting correctly, then had some much more experienced guys at my shop look over the stuff I did to make sure I didn't miss anything. The bike ran 100% but I learned the hard way that it dripped gas out of one of the carbs when sitting overnight making a mess everywhere and hydrolocking the motor.

Again, I took the carbs off, all the floats are sealed down, jets seem fine, can't find anything wrong, put it all back together. Ran fine for a few days, then suddenly while in bad traffic at 7am suddenly bogs down and dies on me. It now sounds like its flooding or something, is impossible to start unless you bump it, and gurgles like its getting too much fuel. I do NOT see how it could still be the floats, I have them set as perfect as can be.

It would be easy to say that the neeldles are in bad need of being set, but this problem is not consistant. it gets bad/worse/bad/hopeless/bad/good/worse while riding. I have replaced all the ignition items and cleaned off the fouled plugs numerous times, all I have left to do is figure out the carb problem. These carbs seem to be impossible to find new ones of now that I need them. Any suggestions on what else I could check inside or out of the carbs would be appreciated.
Thanks, Sam

BananaKatana wrote:A$$ Gas or Grass, Nobody rides for free

I would like to be paid in grass, please.

You're probably on the right track, intermittent carb overflow is usually a float sticking. In your case, it is probably only happening when one or more floats have enough play in the pivot mount to allow either the float or the bracketry on the floats to catch something else inside the floatbowl. It may not be easy to see what it is hanging up with the floatbowl installed, so you may need to look carefully at both parts and try to imagine what-is-where when it's all together, and what could be snagging when it is.

Just a quick suggestion. Make sure your floats aren't leaking. I mean the actual little air filled float. Sometimes they spring a small leak and fill up with gas. Then they get stuck open and gas pours into the float bowl uninterrupted.

Either take it out and hold it under water, or take it out and shake it, if it bubbles or sloshes you need to replace it.


It's more likely that you need to clean the float needle, jet, and seat. But it's a possibility. Double check your float heights as well.

I did check/clean all of that, with the exception of the hole-in-a-float possibility you mentioned. And buzz, I was trying to imagine what they could be getting caught on last time I was in there. The intermidtency points to a problem with the floats, but I can't find anything wrong with them for the life of me!!! Time to crack em open again.... thanks, Sam

No offense, but just because you think it's clean doesn't mean it is. I've had to clean a carb 2 or 3 times before to actually get it to work.

Do it again, double check the floats, set the idle and sync the carbs.

I will post pics of the floats/carb internals when I get home from work, maybe you guys can tell me what Im doin wrong here.

BananaKatana wrote:I will post pics of the floats/carb internals when I get home from work, maybe you guys can tell me what Im doin wrong here.

Yeah, yeah, yeah..... but where's my pot, eh?

Sev wrote:No offense, but just because you think it's clean doesn't mean it is. I've had to clean a carb 2 or 3 times before to actually get it to work.

Do it again, double check the floats, set the idle and sync the carbs.

Not to mention the fact that the internal parts that you can see can be gummed up and the carb can still run fine. It's the little passages inside the carb that you can't see into that cause the issues. Plus, the float needle is what controls the fuel flow, so that could be sticking or inoperable.

Whenever I have had carb issues and people have asked me if I cleaned them good, and I say yes, they tell me to do it again. 9 times out of 10, they are right too.