The task is to assemble a scooter from scratch, and if possible without any financial investments, from the old spare parts that were sent to me.
Thanks to the subscriber Maxim Vasilievich who sent all these spare parts, it is from them that I collect the scooter.
In this video, I planned to install a piston cylinder and assemble the engine a bit to quickly install the engine on the frame, usually it does not take much time.
But as it turned out, a surprise was waiting for me, the fact is that the piston does not reach the top dead center, and there is no compression ...
I don’t know the real reason why this happens, in my opinion there are 4 options:
1. A short connecting rod is installed on the crankshaft, as it can be seen that it is not native, but SEE
2. A high cylinder, therefore not from this engine
3. Short piston, apparently not from this engine
4. The manufacturer, specifically limited engine power in this way
Having measured all the pistons that I had, I came to the conclusion that the piston from the Yamaha scooter is ideally suited for height, I decided to install it, thereby eliminating the piston’s shortage, while in the extreme lower position of the piston, the cylinder’s purge windows open completely.
One question remains, will the two holes that are present in the Yamaha piston skirt interfere with the work? At first I thought to weld them with argon, and remembered that one subscriber has exactly the same AB07 scooter that he restored, and I decided to ask him about it.
Alexander confirmed the possibility of installing a piston from a Yamaha scooter on an AB07 engine, according to him, he did the same, and everything works fine.
Thanks to Alexander from Storozhinets
But still it remains a mystery, why is there a piston shortfall? How could the engine work under such conditions?
After all, this cylinder was installed, as a proof the pin is one more than the others and converges with the threads in the crankcase, and the video shows that there was carbon residue on the cylinder liner, which indicates that the piston did not reach the very top during operation, I can’t even imagine how the engine worked ....
My Instagram: samodel_workshop
28 сен 2024
