I would like to remove the flywheel on my 72 RT360. I have the correct flywheel puller I believe but am having trouble removing the central locking nut and washer. The flywheel turns with the movement of the socket wrench. How do I stop the whole thing turning so I can get purchase on the nut?
Thanks,
M

There is a proper tool, but I'll leave it for others to comment on the dos and donts of using one of those. However, if the engine is in the frame, chain attached, rear brake attached and working, then you could stick it in gear and get someone to stand on the rear brake pedal whilst you try and undo the nut. I can't guarantee that it will work, but it's worth a go.

Good strap wrench works and is my favorite method.  Lawnmower shop might have one. 

I've found this one to work well:  www.amazon.com/gp/product/B0011E4QU4/

Pin spanner of correct size can be made or bought.  Make sure pins aren't too long to go in past flywheel windows and foul the internals.

Motion Pro 08-0008 holding tool is a combo pin spanner and clutch hub holding tool.  Good to have.  Knock off versions are out there too.

Easiest way to loosen is electric or air impact wrench...  but then you still need a tool to hold and get re-torqued properly.  And you need to make sure you torque an RT2 flywheel properly.

I wouldn't try something like a good size piece of wood in the exhaust port to bring the piston up against--or wood i!!--done worse. Or rope fed down the plug hole to build up a coil of rope to stop it above exhaust port. Best find a piece of flat steel or solid wood & cut it to length then sit it against one of the two flywheel slot ends on a severe angle back to the footrest so it'll stop it solid then undo the nut. Same in reverse for tightening it. If you get the nut off then make sure you remove both spring & heavy flat washer so the puller gets full depth of thread as its a fine tread & easily damaged. Also puller center bolt backed right out so ya not tricked by 'that' pumping the shaft before the outer puller is fully threaded in. Or purchase a proper tool.

& here's my holding tool, just need to be careful the pegs don't protrude through & damage the coils. 

Cheers Buddy, just ordered one looks almost exactly like this from eBay.

Thanks everyone. appreciate the help. I've ordered a tool that I hope will do the job.
Fingers crossed.
M

I'm sorry I didn't see this topic sooner,  The tool that RT325 has is the correct Yamaha tool.  The number 01235 is stamped on the tool.  If anyone else is interested in this topic, here's some additional information . . .

The "official" Yamaha tool:

 

 

There are lots of alternatives too . . .
(Just a couple of examples from ebay. I haven't used either of them and this is not an endorsement)

 

 

Spending a few bucks for a good tool is a lot (a lot!) less expensive than repairing your engine and/or gearbox. I'm just sayin'.

Nice find on that Yamaha tool.  Thanks for posting!

For a "mechanical" holder I sometimes use the Motion Pro Universal clutch holding tool...  the pins on the back side.  I prefer the strap wrench but if I had the Yamaha tool I'd be using that.