Tech Zone > Skill centre

Generator removal


There are still a lot of keen motorcyclists that are not sure how to remove the starter / generator that is fitted to a lot of different early model Yamaha two stroke engines.
There have been a lot of posts on various sites with people responding as to how to remove it. A lot of these ideas are incorrect and will end up damaging the rotor windings.
I have added a few pictures to show the correct tool to use for the removal of the generator.
First pic is the Puller Bolt. This has a thread of 10mm x 1.25 pitch and has a reduced end of 5.5mm x 30mm long. Bolt overall is approx 100mm long.
2nd pick shows the bolt screwed into the generator, with the reduced end sticking out from the tapered bore.
3rd pic shows the crankshaft taper with the hole in the end to accept the reduced diameter of the bolt.
4th pic shows the hole in the end of the crankshaft taper where the reduced shank of the bolt enters.
5th pic shows the reduced shank of the bolt entered into the crankshaft taper.
It is more or less self explanatory, but basically just screw the bolt in all the way until about 30mm of thread is left showing. The bolt should now be tightened up, but do not over-tighten! A sharp tap with a hammer on the end of the bolt should free the rotor from the taper.
Make sure you place something soft below the generator to prevent any damage to it, if it drops off.
If anyone needs one of these bolts, I have two (2) at £10 each plus £2.50 postage within the UK. - Now sold

It's nice to have the right tool.
Would it also work if it was in two pieces - a threaded screw and a pin?
That would be easier to arrange than a specially adapted screw.

I think that using a bolt and a pin may work but you might find that with it being two pieces of metal the ends may splay and cause it to get stuck, one piece is stronger than two.

Astute Greaser:
Variation of Puller bolt
Its both the jack bolt and can use the weight from slide hammer if fails.


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