I've already written one review for this engine. After a couple of months I'm still happy! Works great in my cub! If you go for this mod, keep in mind that you'll need to put a lower numeric gear on the rear or otherwise first will pretty much be a granny gear!
The engine almost always starts on the first kick. It's a six-volt so all the old cub lighting will work without modification. I thought it was 12 when I got it so I spent a little time wondering why my nice rectifier wasn't putting out any current. (face palm). TBolt has the correct rectifier available.
I can't say enough good about this engine! I'm eager to try the 140cc version on another project!
http://www.youtube.com/watch?v=-SvPVmwrqwE