My old swingarm (the one that broke)
http://www.ukmonster.co.uk/monster/s...ad.php?t=60544 was from an 851/888 and it was wider at the front than the Monster arm that I replaced it with.
It was as wide as the M900 spindle was long and so, whilst it fit it didn't protrude from the ends of the arm meaning, I couldn't fit the circlip.
This was OK as the bolt clamps it in place until of course the the arm cracked and the spindle slid out, something that wouldn't have happened if the clips were in place even with a broken swingarm.
I seem to recall you saying you had an 888 swingarm? I don't know if they used a longer spindle or just didn't bother with the clips? (maybe they added the clips after a few spindles slid out due to broken arms?).
I do know that the steel arm spindle as per M600/750 is shorter as the arm is narrower due to being made from a smaller box section, how long is your spindle?
As per above, powder coating on the inner surface is no good, it will wear off and then the swingarm be loose. Also, when shimming check the sprocket alignment, mine was well out.