I've got(had) 2 .21 vgs, one stock and the other is the Hot Mod version that I run in a buggy. The stock one was good for exactly 2 gallons. I used it mainly for practice days and as a backup motor. I put in a new piston and sleeve and I got maybe 1/2 gallon through it (after break-in) before it "locked" up while idling for about 15 seconds just after I started it up. I pulled it apart to see that the top of the piston had scraped the side of the sleeve. It pushed metal up like curled pencil shavings until it got deep enough to stop. I think the cause may be the rear bearing is going bad. Since these motors were new the one thing that was noticeable right from the start was how smooth the hot mod version felt when turning it over by hand. (It has an upgraded rear bearing)

The Hot Mod has about 2.5 gallons on it and still runs strong. The difference in power is like night and day. I can easily clear triples that the stock version could not think about, and on occasion I find myself running up someone elses a#@end down the straight, definately something the stock one could not do.

This is my experience so far....... and I definately will not buy another one. The Novarossi 3 port will be my next mill. More punch and faster than the modded vg, and from what I have seen they are reliable and last a long time, and they're cheaper.

TC