Hi Tech Heads again,
This one is for the jetting experts,
We've been playing with this thing (74 CZ 250 pictured in my Dry Clutch thread) and I am determined to get it running it's best, whatever that is!
We are running it with Castrol TT at 33:1.
I have been adjusting the pilot air screw to find the optimum setting for the bike and with the current pilot jet I have been able to lean the screw out to the point where it won't start at all, no matter what I do, bump start, kick a million times, it just doesn't have enough fuel to kick. I have found that as I screw the screw in, make it richer, I can get the bike to a point where it will start quite reliably after the 2nd or 3rd kick, so I figure I must be pretty much in the sweet spot.
My question is why does it still smoke so much at idle? If I have the jetting just rich of too lean, then I thought the idle should clean up. Is this just a trait of these old bikes or is my understanding of how to tune the jetting missing something?