Good to hear you Husa, after all.
Yes, this is very first version 129cc, with main (upper) piston 57mm and lower 38mm stroke 50.6mm, pumping capacity lowered from 129cc to 71,7cc, so 44.4% reduced. And maybe because of that, zero torque at mid range ( 3500 to 7000 rpm) on all three versions (with two different cylinders from Honda Ns and Cr and three different pistons). Good example where “compressors mode” is needed when engine is off the pipe range.
In this video main piston is seized, only after I decide to test with very small amount of oil in fuel 1 to 100 and too little clearance for 2618 alloy piston .
Good progress in upper range was with Cr 125 cylinder (with 58 mm main piston) at latest tests, but broken piston ring (simply because forget to adjust ring gap) destroy piston and this is where I end and so much left untested.
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