Hi,

does the starter run really fast? With a singing, hissing sound?
Then it should be the starter clutch (german: Anlasserfreilauf), left side of the engine / crank case, looks like a tin can. If You can turn it in both directions, it's rotten inside. Notice: As this part is actually not important (!!), many people here block it by welding. If You have no equipment for welding, You may drill some holes in there and put some screws (use loctite) in to prevent the clutch from running free. The part can also be fixed, but this means You would have to open the can and replace the tiny bolts in there, as they are not round any more. It does't take more than that. I have done this before and would do it again but it requires some patience ... .

Cheers,

Stefan

Yes, the starter clutch is part no. 1 in this picture. The part is not meant to be opened, but one can do it with hammer and chisel or some strong screw drivers used as chisels.
Sounds: You should hear the starter running free, because it's much faster and sounds somehow different, as it doesn't have to move the engine but only the starter drive and this clutch.
To get to this part, You have to remove the crank case cover on the left side. You find it just behind the gears/wheels of the starter drive.

Good luck,

Stefan

There is a fast alternative carried out with a shim (hopefully still available! Yamaha no .: 1J7-17537-YO-30 see technical info => miscellaneous => "Eppo Karsijns"). Works without motor cover to dismantle.
Good luck, Werner

Hello
What are the dimensions of that shim 1J7-17537-YO-30 and why should it mount.

In an earlier post for the repair of the planetary gearing, the mass have been identified:
Rolling bearing shim with dimensions 62 X 50 X 0.1 mm. I have not measured it. Another Yamaha Part Number: 156-11563-00

greetings, Werner