Originally Posted by Inane Cathode
PS How sensitive are these 70s two strokes to main jet sizes, anyhow? I can't imagine two sizes making a giant difference in rideability.
not terribly... i have to go up/down 2 on my '77 IT 250 depending on the season and it's a mild difference.
too rich vs too lean, one really easy way to tell: get on the throttle. listen to the bike and see how it feels. now engage the enricher ("choke") and do it again.
better with the enricher on? you're running lean.
worse with the enricher on? you're running rich.
no change? either rich or the enricher is hosed and on all the time.