Re: Preplexing Engine Issue
I also like the muffler and air leak in crankcase issues. Vespas are notorious for case half leaks and these china motors are the 2 half type as well. The way to check for crankcase leaks is to squirt something volitile like starter fluid or brake parts cleaner anywhere it may leak. While At idle if the idle increases as you spray around you found the leak. Behind the magneto could be tough to get to. Locktite gasket eliminator(grape jelly) works great to seal case halves.