My mate used to race a Krauser 80 back in '91. Man that thing was quick.

It was hilarious as he's about 6'4" trying to squeeze onto a toy. He did win a lot of races on it, but most of the competition was YZ/CR80 motors in AR50 or RS125 frames.

It made something like 33hp @ 13,500rpm. It wouldn't pull below 11,000 and revved to just over 14,000. Faaaaantastic.