I wonder if you're running lean at cruise speed (wouldn't be affected by messing with the mixture screws, those only fine-tune the idle mixture). A lean mixture would run rough, backfire, and burn plugs -- as well as pistons -- do make sure you figure out your issue before that happens!
Have you changed carburetion in any way in connection with your major rebuild? Any change to the camshaft or intake manifolding? If you changed cam or manifold to where you're moving more air through without rejetting your carb to match, that could be the problem. -- You received this message because you are subscribed to the Google Groups "UnifliteWorld" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/unifliteworld?hl=en.
