Umm, I believe there is already a forum for your redundant request and it can be found here: High Performance Bicycle Engine Tips
http://motorbicycling.com/forumdisplay.php?f=13
BTW.....you ever gonna build a 4-stroke biknut? Just curious.
I was thinking there's a big difference between a high performance tip, and a highly modified motor.
If the only thing I could get was a 4 stroke I guess I would build one, but so far I haven't seen a 4 stroke MB I like as much as a china girl.
I'm kind of tired of 4 strokes anyway, that's all I've ever had since I was 15. I consider a 4 stroke a poor candidate for a motor bicycle. The only good reason I've seen for having one is, kits are available with 4 stroke motors that are considered more dependable than a china girl motor. I guess that has a lot of appeal to noobs, and people lacking skills. Aside from that any 4 stroke I can think of either weighs too much, or is too underpowered, or both to make a good MB. I don't want to have to peddle a motorcycle sized bicycle, and if it's never peddled, why not just call it a motorcycle?
A china girl motor is the perfect motor for our purposes. It's lightweight, has capability to make good power, and is very simple to work on. Without much trouble, or expense, they can be made just as dependable as a 4 stroke imho.
But if you happen to know of a 4 stroke that's as light as a china girl, and makes as much power, and doesn't cost $20,000 let me know lol.
That's just my opinion, not meaning to knock anyone's 4 stroke MB experience. I realize everyone likes different stuff, and has different preferences.