MOPED ARMY

By the way...when you raised the exhaust port you also lowered your trapped compression ratio. http://www.torqsoft.net/compression-ratio.html

that would explain a lot. for some reason I thought I read somewhere that 65 was stock on it. babbittsonline lists stock main as a 65.

You're kidding, right? You didn't even click on the link?

anyhow, it ran with the 85 jet but not like it should - according to my friend. He tried a 90 jet and he couldn't tell a difference but I think it ran worse. So I tried an 80 jet thinking maybe it was too rich and it would just cut out again.

I went ahead and replaced the crankshaft bearing seals. Switched the carb again and it still runs like shit. When you first start it, you can't get it to idle unless you turn the throttle stop screw all the way to the right so that the slide is fairly well open. It acts like it wants more air as it spews out smoke at idle and barely maintains an idle.

Thinking we may have opened the exhaust port too much, I even switched to an unadulterated stock cylinder and no change.

At this point, I'm thinking maybe the reeds are hosed. At idle, it seems way too rich but it would rev like crazy when you coaxed it enough and almost seems to be too lean at full throttle. Or perhaps the exhaust is clogged? any thoughts? timing messed up - but this is fixed timing? (edited)

After all this rejetting have you put in a NEW spark plug of the correct heat range? May be all that's wrong.

I'm going to check spark and try new plug. If spark is poor and new plug doesn't help, i have another coil, stator, and cdi i can try. if spark is fine I'll look into the exhaust cleaning.

Ok spark was poor. A new plug and different boot fixed that. Now it starts much easier but still runs poorly. I put on a different exhaust. No change. I check the reeds - they were fine. I pulled out the timing gun - if I did it right - timing is off. I think I did do it right because I checked the timing on an nu50 and it was right on. Different CDI did nothing. So I assume it's the pulse coil on the stator. I'll switch that out next. I guess "fixed timing" is relative on these bikes if some component goes bad.

See? You kept at it and got your reward.

not yet but it runs right now. (edited)

There are. I can test it. I probably lost some hair on this one. Of course the weather sucks now for riding. We put the proma back on and are looking to give it hell. But in holding pattern now. (edited)