Hahah, donuts haha. Seriously, I lowered mine down with 300ex shocks in the front and a 2007 R6 street bike shock in the rear also. It works good for donuts hahahahaha
http://stores.ebay.com/ASV-Inventions_Quad...4QQftidZ2QQtZkm
You just have to watch for some starting at .99cents. I got both clutch and brake levers to my house for around $30 or so. You couldn't tell that they weren't brand new and they have a 1 year warranty.
Do you know any dirt track or mudrun guys? They are most likely burning race gas or will know where to point you. I get 111 from a little mechanics shop called the hometown auto doctor, and he doesn't even sell gas!
I agree however if he pulls the domes and they say 21cc right on the side, (not 17), then he wouldn't have to mess with manually cc'ing. 135 with 21s would be about right.