I have a situation that is stumping me. My 650 has 29 mm Mikunis, 117.5 main jets, 17.5 pilot jets Pod filters, and a Kerer pipe, stock everything else (including points igniion). It was runnig kind of bad, but running strong on all four. The bike ran GREAT last year with no funny popping or cracking. I decided that a valve adjustmen probably hadn't been done since Carter was president, so maybe that was it. I had ZERO clearance on all valve except #1 exhaaust. All valves where adjusted to between 4 and 7 thousanths. Cams where replaced, all timing marks lined up as per manual, points adjusted, carbs drained, new fuel filter, and even polished some of the engine!!!!
NOW the bike has a running disorder (I thought it was in shock). The bike runs like a scalded dog under acceleration. Stronger than ever. It used to have a smooth tone at idle, but now it sounds like it has a miss at idle and at steady RPMs while riding. It acts like it is fuel-starved. When the throttle is opened and accelerating it smoothes out and runs normal. Here are the things I have checked:
Spark advancer seems to operate fine
Fuel system clean and not restricted
Old plugs showed a little lean but I figured that was from tight valves
Points gap properly adjusted again
all points and backing plate screws tight and not slipping
Float bowls drained just to be sure
Fresh gas just to be sure
My best guess was weak coils, but I think they would break-down MORE under acceleration rather than idle or steady RPM. My big brother thinks I need to raise my needle jets a notch. What does anyone else think?
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