I got my new carb, a VM18, and reeds last week and i decided to bolt everything onto my NC50 (with a recently bored intake, stock exhaust) today. I've tried every jet I have (70, 75, 80, 85, 90, 95, 100) and no matter which one I have in the silly thing fourstrokes like mad. What jets do you guys run on your carbs to get the stupid thing to run right? What can I do to make it run right?
Puch 70 treat kit 80 I think I had.
I basically have the same configuration as yours, except for a Vm16.
I had the same problems. (Nc50 1981)
At this point, you have a exhaust issue: you must increase your outward flow.
Gut your stock exhaust or change it.
In 2 cycle engines, exhausts must match engine size. (very important)
At least get your stock exhaust clean as a whistle. (inside of course)
Then, a jet in the 85 range should fit....that's what I have.
If you're four-stroking, you're running way to rich: reduce your jet size.
Check your spark plug, it might be fairly black...which is not good.
It should be light chocolate brown.
Your four-stroking might also be the result of unburned gas back flowing from the exhaust...again caused by your to large jet.
Took me 2 weeks to figure this out.
Keep it up, you're almost there.
I'm cutting my exhaust open and gutting it this afternoon. You think that some pipe solder would be enough to close it up? I'll let you guys know how that goes.
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