The engine is not a fixed speed, it has a throttle lever on it. I
looked it up at small engine warehouse
http://www.smallenginewarehouse.com/....asp?PN=121432 and it is
designed to work with the troy built horse tillers. So I don't think
bouncing around is a problem since tillers will bounce around a lot
more than a mini chopper on the street.

Here is a .pdf file of my engine
http://www.smallenginewarehouse.com/...ngs/121400.pdf and a
..pdf file of the 'go kart' engine
http://www.smallenginewarehouse.com/...ngs/135200.pdf. These
are a 1 page drawing and description showing hp curves.

The RPM range looks to be the same on both 1800 to 3600. My Comet
clutch enganges somewhere between 1800 and 2200. And my engine has a
lot more HP at the lower RPM range than the go kart engine. But I am
not sure if the 1800 is the minimum RPM. Sounds kind of high.

As Roy mentioned, he uses the Intek engine series, which is what my
engine is. Maybe B&S has qualified their go kart motor to be legal in
go karts for resellers.

I'll probably give B&S a call tomorrow and see what they say. But as
of now, I can not see any reason why the 120000 series engine I
purchased would not be a good choice for a mini chopper.

Thanks.