It's all Matt's fault, this is one of his Chinese saws that he had fixed up. He has the old style BB kit on it, the one with the black fins. It also has the new carb, big filter, big spikes, roller chain catcher, yadda, yadda - it should work out well as my bucking saw. I got a good deal on it (he may have been sippin' the furniture polish)
If the stock port numbers I got from the threads is correct, the stock 365/372 has 24 degrees of blowdown. Both Will and Andy indicate that the engine runs good down to 20 degrees. So with a bit of port work and trimming the piston crown, I may be able to get the transfer flow up closer to the factory design parameters for the original 365.
It's a half-azz approach to porting, but then we just had a thread where we were discussing hacks that port their own saws - must be some sort of syncronicity.
It would help if I could get ahold of a 365 jug, measure it up and then compute the time/area for say 10,000 rpm. Then I could change the displacement in the formula to 76.7cc and work back to see what the timing should be to arrive at the same time/area for 10,000 rpm. The alternative is to use Blair's figures of .0066 m/sec at the desired rpm.
However, before I go diving into the guts of this thing, I've got to spend some time filing the new chains to see what works best. Once I have maximised the potential the the chain, I can then work on the potential of the engine.
I must get my butt into gear and do one of these kits Matt sent but I'm still waiting on parts. ####ing takes forever. The Chusky with kit piston is ex 158, trans 118, in 160. I will be bringing the ex and trans up a tad and a tad more width at the ex.
