I have a 2007 GN250, i Have swapped out the exhaust on it for an aftermarket one. I am finding that if i have the idle around 1500rpm (as is meant to be) it bogs when warm and i open the throttle to pull away lights etc. I have screwed in the a/f screw as much as possible as I believe it is running rich (the choke is fully pushed in also). I believe it is running rich as the stalling problem gets worse when the a/f screw is turned out to 2+ turns, and when I fire it up after it has bogged (or if I manage to catch it before it stalls) then the smoke coming from the back is black. This generally happens when the bike has had chance to warm up. If I wind up the idle screw (the one that adjusts the resting position of the accelerator) it seems OK but of course it is revving its tits off at 2500-3000rpm.
I tried removing the air filter and twisting the throttle then to see if that was preventing the air getting through the system but made no difference.
ANn suggestions or is my next stop a carb removal and clean (checking the pilot jet thoroughly),
Cheers
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