Mr. Pipercub has the right idea. I don't have a bunch of experience putting converted saw engines in r/c planes but in kart/scooter/bicycle kicker conversions, that is how it is done. There should be a blank boss or two on the cylinder that could be drilled and tapped for use as a headstay to keep vibration down a bit. That engine might/should have a spot for a compression release as well.

I think it would be very cool/interesting to use a saw engine's oiler(or oiler drive) as an hydraulic pump for retracts. Or for a smoke trail setup.