What causes carb backfires?

[Anonymous]

My number two carb is backfiring while the other three seem to be doing just fine. What causes a carb to backfire and how does one fix it? I am sure there is no ONE answer, that would be too simple, so a list will be nice.

[Anonymous]

First thing to check is your valve adjustment, you may be way too tight on the intake to that cylinder. If thats good, do a compression check. If your timing were off, you would be backfiring through two carbs.

[argonsagas]

If a carb backfires, the reason could be valves, but more often tends to be ignition timing.

First (and easiest) thing to check is your firing order. It is not clear whether you have two or four cylinders. Most Suziki 4s use coil one to fire cylinders 1 and 4 and coil 2 fires cylinders 2 and 3.

Unfortunately, you did not say what you are riding, so I can't go farther in any direction.

[Billy Ricks]

Ron, read his post again. It's a four cylinder 750. Most likely a valve that's too tight.

[argonsagas]

Billy...you are right.... .

About the fine print and the cause....if it is only one cylinder of four then it has to be valves.

Kevin, I apologize.

Think I should call it quits for the night and get some sleep.

[Billy Ricks]

Ron,
I've had plenty of days like that. Hopefully it's just a clearance problem and not a burnt or bent valve he's got.

[first timer]

you can also try checking to see if your intake boot to that carb is leaking. i find the easiest way to check is get one of those cheap propane torches, start your bike let it warm up then turn on the tourch ( DO NOT LIGHT THE TOURCH) just let the propane blow out and around the boot and see if that effects you idel. if your idel increses then you probly have a leaky boot.

ryan