How to i take an alternator rotor off a motorcycle crankshaft ?

Its a yamaha rs 200 1981, i need to change the rotor but cant get the old one off, It will not come off though. I asked people who say it just pulls off a key, and use leverage to get it off, so i used the end of a hammer but it bent...so did a shovel. So i got my friend who is an engineer to try remove it. First he heat treated it and then used a HUGE big puller on it which started to bend the crank shaft rather then slip off the rotor, Any last thoughts before i cry ? :-/How to i take an alternator rotor off a motorcycle crankshaft ?
I'm not familiar with that model.

This is the most popular flywheel puller for that era bike.

http://www.motionpro.com/motorcycle/part



When you remove the nut, holding the rotor to the crankshaft, are there internal threads in the recess of the flywheel?

If so - that is the proper tool.

Measure the thread diameter to double check.



Same design 30mm

http://www.denniskirk.com/jsp/product_ca



A big puller will warp the flywheel, causing it to grab tighter onto the crankshaft.

Same thing when trying to pry it off.How to i take an alternator rotor off a motorcycle crankshaft ?
impossible you may need to grind/cut it off