Today I was painting my bike and noticed that the left cylinder is running richer than the right (by left I mean chain side, right exhaust side). I looked into the exhaust header and the left is much more carboned up than the right which is much more normal looking and has a brownish white tint to it. I also have had problems fouling plugs on the left side. Ive heard of doin a carb sync I dont know if that needs to be done or what the deal is. I also know that the left carb has a vacuum line going to it from the petcock, would that have anything to do with it. Let me know what you think.
Your exhaust pipes should look the same. You have something amiss, that could be related to carburetors, ignition, or engine mechanical condition. The pipes are a short-term indicator, but since you mentioned that you've been fouling plugs regularly, it evidently has a chronic condition.
You could have carbs out of sync, but I doubt that it alone could cause the problem. A carb sync aids in low speed operation, and is less noticed as revs increase. You could have other carb issues, such as incorrect float levels, throttle slide sticking, or a choke valve slightly sticking.
Your ignition has separate pickups and coils, which can also cause differences in ignition timing between cylinders, and strength of spark. You can swap coils to troubleshoot this problem. For the pickups, you can manually check the air gap between the trigger and each pickup. I'm not aware of a spec for this; just adjust the pickups to make the gaps identical. Of course, the spark plug gap is most important; make sure they're gapped the same and are in good condition.
Your problem could also be caused by significant differences in compression between cylinders. This is more likely in older engines (30K+).
Regardless of the cause, here's hoping you find it quickly and it's a cheap solution. :cheers:
Yea Im leaning toward something in the carbs, because my bike is a 93 and only has 13,000 miles on it. I think Ill put a compression tester on it and go from there but judging from the thumb method both cylinders seem to be the same. My bad to I kind of miss lead you on the plug fouling, Ive lost one on that cylinder. One other thing is that that cylinder doesnt always fire when its cold and at very low rpm's. Any ideas are welcome, Thanks.