Mill motor hop ups

[thechknhwk]

Anyone ever hop up their sawmill motor?  If so what did you do.   I used to race quads and the 25hp kohler had me yearning for a bit more power, so I was thinking... Hey maybe I could get a free flowing exhaust, but other than that I have no idea what ya do to a  lawnmower engine.

[MEMountainMan]

Try an offset key to change the timing, polish the ports and valves, open up the exhaust, have the cam twisted and reground for more lift. Personally I wouldn't do anything to the engine to make it racey. Any mods shorten the life and when it seems to really get screaming after the mods that's when a rod breaks and comes out the side of the block. I'm interested to see what other suggest. Good luck with it, Mark

[thechknhwk]

I was thinking intake, carbueration and exhaust.  That usually won't hurt a motor any as long as the filtration is adequate.  That's all I used to do to the quad motors and that would get ya about 10 extra ponies without sacrificing reliability.

[pineywoods]

Nox in the air intake, nitro in the tank ? Hopping up air cooled engines really not a good idea, not much way to add more cooling..

[hamish]

Try looking at it from another perspective, find the peak torque curve of your motor and work around that.  Max rpm on the wrong side of the curve will just take a dive, the only way to recover is to stop or slow the feed rate to allow it to recover.