sputter on inital throttling

[kamanarnow]

Ok guys my question is this. What would be the cause of the engine sputtering slightly during idle and most noticeably during the initial throttling from nutrel to first gear. I have only synced the carbs using feeler guages to get the slides to a similar level. I don't have the 4 carb sync tool neccicary to properly sync them however I know it can't be to far off on the vacume because the bike does get up and go and once enough throttle is applied I can move from neutral to first with out that sputter but it has to be a heavy throttling in order to do so. The timing on the bike is spot on. I have checked and rechecked the points several time. Also I have cleaned all jets and channels the jets feed into several times. The bike is a 1976 cb750f with an 836cc. Big borr kit in it. It has 4 stock slide carbs with 4 pod filters (don't have stock box air filter) and a 4 into one exhaust with no muffler attactched. ( sounds mean as hell) . any advice would be welcome. Thanks guys

 

[amc49]

Sync is more about pulling away from idle at very low throttle than at wider open, the percentage differences in unsynced carbs become smaller with larger throttle openings.

In other words, your sync theory is backwards.

Whichever carb is too far open has already used up some of its' idle progression fuel, when you open the throttles to go off idle that one spits because it's rich then goes instantly lean.

You can clean jets 50 times and if they are still plugged in some way a waste of time. You instead must ensure all carb fuel circuits are fully open and working, not just jets.

If plugs are wet or black can do it too. They try to short down the sides of the porcelain under load.

If engine is off in compression will spit like that too, weak cylinder not accepting work like a lazy boy.

 

[kamanarnow]

You have given me much to think about. I have made sure that the carbs and all fule lines are fully open. If after a good quick throttling the bike seems to decrease significantly in idle to the point the bike almost dies be caused by a carb slide being higher than the other.? I can go a head and check the cylinders for compression but I don't have the tool to measure it. Would a faulty spark plug coil cause the sputter ?