OS 40 LA & 46 LA with YS system

I was surprised to have disassembled OS 40 LA and 46 LA, precisely fine machined technology including metal casting accuracy & finish, bronze bushes were inserted by means of simultaneous casting method at necessary portions in the case, supporting crank shaft. Cylinder sleeve is thinner utmost by cutting method but later changed into Flange rolling method.
Although they do not have crank shaft supporting bearings, according to my perception, they are not always necessary for ordinary use if the motor is used under 12,000 rpm, rather than I would be released from some troublesome bearing maintenance cares, lighter and thinner motor design is preferable if the displacements are the same.
100 gr weight on the fuselage nose portion influences a fundamental airplane designing relating on the nose & tail moment ratio, CG position.
Setting a pressure fitting on the motor cases are the same as the manner mentioned before including crank shaft pulse width grooving and carburetor throat drum modification. The carburetors are replaced from original ones to OS 2C for car racing with 7,0 mm throat diameter, not only for ultimate power but they have fuel squeezing mechanism at the lowest operation.