Which woodruff key for Rd250/400 flywheel PMA

[alexml]

Hi

Anyone know which is the best size woodruff key for a DIY PMA set up. I have the RD250/400 aircooled flywheel, but no idea what size woodruff key will work. Not even sure if the key is larger on the XS or the RD. I was hoping not to buy a load and try them out. I am sure someone has the answer. Thanks

 

[MartinNC]

Hi

You need to make a stepped key. The slot in the crank is narrower than the slot in the flywheel. Measure the two slots and choose the largest and then file to suit. Alot of people don't bother with the key. The key provides location only, the drive is through the taper. On my set up using an LC flywheel the larger slot was 5mm so that was the size of key I bought and then filed the step to fit the crank. The advantage is that you can mark and keep your timing marks

 

[kevski]

4mm slot on crank 5mm on flywheel when I bought a PMA it came with a 5mm slot and a 5mm key I just carefully filed down the key on both sides to make the step until it fitted and hey presto it worked.

 

[Signal]

Buy a key for the RD rotor then compare it to the XS one. File it to fit. Here is a photo of one, it is for a LC/RZ 250 rotor.
From memory the RZ key had a larger diameter as well as width than the XS key.
As Martin MC said the taper does the work, the key ensures your timing marks are accurate.

 

[angus67]

The key for the xs is4x5mm, half elipse. From prevoius posts, sounds like a good starting point

 

[alexml]

Hi all, thanks for the info. I will get a correct sized key for the RD flywheel and file to suit the XS. i would like to keep the timing marks, so will go with the key.