Dirt Bike Repair & Maintenance Forum

Yes I know what you are thinking...dirty carb, worn out top end.  But you would be wrong!  lol I just rebuilt the engine. New crank seals, new top end, reused the crank, and all components were good just had to use a "B" size piston to make up for enlarging cylinder, since i didn't want to spend the money to replate.  Reassembled engine, clean up powervalve and verified that it is operating normally when unit runs.  But I can't get the thing to idle.  I went leaner on the jets since it felt like it was just too rich.  Still didn't help, inspected reeds and found that Boyesen PowerReeds were installed, and on one side it was done correctly, and the other side they were installed ontop of the stock reed. Making that side too thick to open at idle.  So i corrected that and the unit runs a lot better, starts easier and much crisper. It seems I got the jetting about right. But the thing still won't idle.  This has the screw for idle as part of the choke knob.  I have it turned all the way out and it barely idles and it has that....I've overly rich sound, which makes sense the choke is constantly on with it turned out all the way.  So i turned it back in all the way and just held the throttle slightly open and it sounds great.  IT appears that the jetting it correct, but just needs more air at idle to sustain it.  I was wondering could have the reeds been damaged somehow by incorrect install? Maybe they aren't sealing at idle and allowing escaping air but the fuel remains trapped?  Does this sound right, or am I just getting wrong ideas?  Please I don't really know what bad reeds do?  I'm at a loss at this time. Any and all help would be appreciated. Thank you