mydogtaz wrote:Recently I bought a Rear Magtek for my MC21 from Japan but it`s a bit different from the existing Magtek rear that is on the bike...........the bearing and dust seal sizes are different for one thing...........Might it be from a RS250 race bike ? ? .....................Can anyone help please.........Thank you.

The NF5 RS250 wheels use 6204 bearings.
The wheels can be fitted to the MC21, this is the F3 set-up. It requires a bit of modification and switching to the NF5 rear caliper too. So might be too much hassle.

For my race bike, I measured up and had the necessary spacers, sprocket carrier & torque arm made. Dan Williams now sells that kit.
Note that it requires the torque arm anchor to be welded to the underside of the swinging arm. A spacer needs welding to the right side chain adjuster too.

I've just had six RS wheels refurbished too!
I got a 10% discount because it was more than two sets, which was a nice surprise.