Hi all

I am having trouble removing flywheel on 1974 TY250 , using the correct pullers time and patients but no budge.

Any recommendations 

Tried giving a few sharp knocks with a hammer on the end of the puller? A bit of heat around the flywheel close to the crankshaft might help, also leaving the puller on full tension overnight.

Lay it on its side and spray wd40 down the woodruff key slot if there is one and leave overnight. Heat gun it  and repeat. 

I recommend not to apply too much heat to the rotor, the magnetic properties will go away if you heat up the rotor too much!

I recommend tu use a heavy puller, the use of WD40 serveral times, some small knocks while the puller is set on
and patience. 

The front gear on a Montesa 242 has the same issue from time to time.

Thanks for the replies, I have soaked in WD and using hammer treatment on the bolt but no budge.

A small bit of heat on the shaft is my next plan.

Try using a low powered electric impact driver on the puller bolt, the continuous shocks might loosen the corrosion between the crank shaft and fly wheel /woodruff key, obviously you don't want to go mad at it as a impact driver will be capable of stripping threds if you could get one you can turn the power down on or something?. There is a spray called shock and unlock, iv tryed it and have to admit its not amazing but if you've tried everything it's a last resort. Maybe wd40 and heat, then shock and unlock with abit of rattling it might pop. 

maybe pour in dry ice in between the crank halves to try freeze the crank axle? didnt try it though myself

13 hours ago, bsw said:

Thanks for the replies, I have soaked in WD and using hammer treatment on the bolt but no budge.

A small bit of heat on the shaft is my next plan.

The heat would really need to applied to the flywheel to expand it away from the shaft. Heating the shaft may have some effect as it’s expansion, although restricted by the flywheel, may just dislodge the corrosion enough for it to lose its grip on the flywheel. If the engines out of the bike why not put the whole thing in the fridge or freezer for a while to really cool it down then take it out & re apply very localised heat around the hub of the flywheel, preferably with a modellers type fine blowtorch. Might just work. I always put wheel bearings in the freezer for a few minutes before fitting, it just takes out the interference and saves a bit of metal to metal contact. Once back to normal temperatures where both bearing & hub are equal, then all is well.

Good luck.

19 hours ago, bsw said:

Thanks for the replies, I have soaked in WD and using hammer treatment on the bolt but no budge.

A small bit of heat on the shaft is my next plan.

You don't want to be using heat on the shaft, that would just expand the metal and make the problem worse. It's the flywheel that should be heated.

Are you using the correct screw in puller? legged pullers do not apply pressure in the right place.

ISuccess at last, I was using correct flywheel extraction tool , there is no room for a bearing pullers.

I took the bike to a engineering firm who i used to give work to ,they allowed me use of a set of gas bottles, acetylene is great to apply heat quickly in a specific area.

Heat on ,flywheel tool on and a few heavy  thumbs of a copper mallet it popped.

Now off to find crank seals, UK is not an option for us now due to brexit.

Does anyone have the seal number to hand, my bike is 1974 I think the seal is specific to that year ,double lip seal with 2 springs.

The seal is an SW-30-55-10, not sure of the Yamaha part number though. You should be able to get it from a bearing supplier.