Re: my opinion on the china girl ..
I'm a retired Master Tech also. I always wanted to build a motorized bike and opted for a cheap China deal. It wouldn't start for a day and Finally found that the plug was intermittent. I've only been riding it for about a week and not too far, just in case it decides to lock-up. Using 16:1 oil and running it for all it can do. I figured I'd try to get it to lesser oil mixtures before trying to recalibrating the carb or using another. It starts quicker and runs better than last week. Also I found out it's only a 70cc rather than the 80cc I wanted. It runs ok with quite a bit of vibration for a small engine. I'm also reading that some of the newer ones have roller rod and wrist pin bearings?? I want to install a shifter kit before I inspect the engines internals, If it runs that long? I seem to have a good one after reading some of these posts, but I'm still skeptical.