GS650GX bogging just off idle and at 4k

[Anonymous]

I'm stumped! My 81 gs650G is bogging just off idle when I start off and at about 4k when I give it gas. When I start my idle sounds pretty good and when I initially start out the bike runs better that it does after about 10 minutes of riding. I just put dyna coils in and new plug wires to try to combat the problem but with no luck. It runs bettter when it's not bogging but the bogging is still there. I have replaced the o-rings on the engine side of the carb boots and I'm reasonabley sure that there are no air leaks elsewhere. I have cleaned (really) the carbs and put in new o-rings from Rober Barr. Since I have replaced the carbs I have not had them syncd and I wonder if that is an issure in this case? I also wonder if it could be the float levels. I have just rechecked the levels and they are at 22.4mm but that measurement is from the bowl gasket base to the top of the float ie. the flat part above the top of the curved part of the float. (if you know what I mean?) I'm wondering if this is wrong and the measurement should be just to the top of the semicircular part of the float rather than the top of the flat stepped up part the tangs attach too? I also wonder if the air screws could be the issue, but as I understand it they only come into play at idle or just off idle until the butterfly opens and the pilot jet takes over. Also I don't knowhow this would explain the bogging when I give it gas at 4k. I'm confused and any help would be greatly appreciated.

[duaneage]

Take it out, run it up to when it bogs, and when it is "bogging" kill the engine and pull a plug.

Black will indicate fuel dumping and white means starvation.

It is unlikely that all four carbs would have the same problem and run rich so let's assume it is running lean. I would look to fuel delivery. Petcock OK? is the vacuum line to the petcock from the #2 carb connected and not leaking or damaged? Try it in the PRI position. If you have a fuel filter ( and you should) make sure you see fuel flowing through it.

[Jethro]

How does your advancer look? I had those same symptoms, it turned out to be my advancer springs were broken.

[duaneage]

Black plus would indicate advance problems, good call Jethro. If they are all black when it is bogging check that the timing advances . My 650 has all the advance in by 3750 rpm.