Old Timer & OS 40 FSR motor

Old Timer "Begin the Begin" is now ready for flight, replacing motors from OS 40LA to OS Max 40 FSR produced half a century ago, that was obtained from Yahoo Auction at 5,200 yen the other day. Though the seller said NIB condition, it has a history to be operated for a while, I could dare say so because clogged phenomenon were observed here and there inside of the crank case. Relatively long period time was required to clean and replacing main bearings. This 40 FSR looks new but mischievous chick indeed, disassembling this a part even piston pin retainers to remove sticky clogging material vanish like sludge every where, troublesome so much. Fully overhauled as matter of fact, all the cranking movement recovered smoothness and keeping compression after removing piston ring for piston groove cleaning, anyway all the performance were recovered as a matter of fact. After all, I wanted to listen to the exhaust note of 40 FSR motor experienced over 50 years ago, this is why I replaced motors for Begin the Begin.