Propped with a narrow type -good solid 26x10-- and using a decent exhaust system -- expect STATIC THRUST to be somewhere in 40-50 lb range .
On pipes , more -- on a shi--y exhaust set up less. We have used these on 27lb models -on cans-wit h excellent performance
on a 31 lb model - - you are out of the high performance envelope - with ANY 100 cc engine..