Question for you motorcycle techs out there who do this every day, one (automotive) tech to another...
2001 Kawi ZX6R, CV carbs
Carbs sync adjustment is performed at idle, right?
When they're synced at idle, they become out of sync at higher engine speeds (no load). At 3 or 4k, they're out enough that the engine doesn't run smoothly. It's not horrible, it just runs like they're out of sync - stumbling a bit. Enough so that I feel it's not running right.
Is this indicative of an additional problem - incorrect idle mixture adjustment, a problem with the diaphragm, jets, needle, etc?
Should they stay in sync through the RPM range, or is this normal?
The carbs have been gone through - the idle mixture adjustment screws were all wrong when I took them apart - someone had removed the plugs and messed them all up. 2 of the 4 were loose, one was 1/4 turn off bottom, and the 4th was bottomed. Obviously, that wasn't right, so I had no reference when disassembling, and the service manual gives no adjustment procedure.
I'm not 100% sure I have the idle mixture adjusted correctly and I'm thinking that could be throwing off the sync. Using my automotive carb experience, I spent some time on them and adjusted each to the highest vacuum (using the manometer) with the smoothest idle, each independently of the others and kept going back and forth between the 4 carbs with the idle mixture and the sync until I was getting a consistent result and a nice smooth idle. But perhaps I should sync the carbs at 3k or 4k to baseline the throttle valves to each other (at that speed, they're off the idle circuit, right?) and then bring it down and adjust the idle mixtures until they're even, then they might stay in sync through the RPM range? The thought process being that if the mixtures are off between the four at idle, this would throw off the manometer reading at idle, giving me an incorrect baseline for syncing the throttle valves.
Thoughts, experiences?
Any help appreciated - I have plenty of professional experience with automotive carbs, (15+ years as an ASE tech) but four touchy motorcycle carbs are a whole different animal! I'd love to pick up some knowledge in this area.