Shoot,

I submitted a post last night to this, but somehow must have not posted. I got a new 25cc trimmer and a used homelite 33cc saw yesterday. Took the trimmer apart, and its a two bolt crankcase, bolt on muffler. Theres an o-ring seal on both the backplate and the cyl to crank, and the cyl bolt spacing does not quite line up with the older 4 bolt cases. The holes could easily be filed to make the cyl fit, but I think the porting would be really off and likely to affect the power, thats a guess cause I didnt look that close before abandoning the idea of using the old case. I wanted to use it because I have stuffed it and had the mount already made, but like you said its not that much work to repeat. The new cyl has a flat base, no ears on it extend into the case, and the o-ring groove is in the case, so it will be really easy to take material off the bottom of the cyl to raise compression. Gonna start cutting on it tonite, I'm still relatively in the dark about the timing and durations, and cutting ports, but I think I can at least get a little more power than stock out if it....what mods did you do specificly to get 8k out of yours on the 16x8? I want to use a Bolly 18x6, I need more thrust than speed with this plane. I really like that Bolly, I have a 14lb or so H9 Tcraft with a G23 on it that flew good on MA wood 18x6, now with the Bolly it leaps off the ground and will hang on the prop.

Thanks again,
David