1980 GS750 Bogging Down

[stuart839]

I have just aquired a 1980 GS 750 G it runs fine to about 5500 revs then justs bogs down and wont pull. I tried cleaning and balancing the carbs and replaced the main jets with what I believe to be the corrrect ones 105's, it was fitted with 115's when I got it.
If I remove the airbox it will run great and smooth right through to the red line. The bike is a Japanese import shaft drive with only 21,600 kilometers on the clock

[justmount1]

have you tried to change your air filter? if it runs just fine when you take off your airbox this may be your problem.

[stuart839]

sorry yes I tried fiting a new air filter and it made no difference, it still bogs down even with an empty airbox and the end panels removed, it only runs fine with no airbox fitted

[80GS750]

sounds like your getting too much fuel.... try to lean it out a little bit more or just buy some pods for those carbs, they will let a lot more air in, maybe that will work.....

[stuart839]

thanks when I cleaned the carbs I checked the needle settings and they were on three as per spec, I'll try resetting them to two and or one to see if that as any effect, when I get some more time.