Crankshaft

In order to make the exhaust note more softer and to obtain the stable low speed operation, combustion pressure reduction was performed by means of inserting head gaskets, two pieces of 0,2 mm thickness. Probably, modification like this would not reduce both power and torque so much, just only some peaky rotation phase in turn.
Engraving the crevice on the crankshaft axial surface adopting with the desired pressure timing and duration independently those have no relations with import timing. By withdrawing the highest pressure only, unnecessary pressure noise that had been caused uncontrollable phenomena would be eliminated thoroughly.
By the way, very small and no getting in the way, YS regulator for YS 63 4-cycle motor had been obtained from Yahoo Auction, the bulk is just a half compared with old ones for 2 cycle motors 40 years ago. The concept, the principle and the construction of this cute diaphragm regulator are not changed if the application of use is different.
Though it is informed that the diaphragm valve spring ratio is higher than before and the ideal adjusting point tolerance is smaller than before, I have enough confidence to Master it enough to obtain the sweetest angular position. Sensitive reaction of the regulator adjustment might need keen concentration, but it means that the reaction might be shown more clearly than old ones instead.
Asymmetric is clear from the back side view, distorted counter weight according to the delay of combustion timing.
Also, picture shows the fine engraving finish on the entrance of the messenger port gas way like a specially tuned motor by the authority, not by just drilling finish.
Anyway, actual operation of the modified OS 55 AX motor prove the result.