I just got my motor back from Gorr - can't wait to fire it up this weekend - and was putting it back in the frame when I noticed something strange.
I was wiggling the swingarm around trying to get it to match up with the engine mounting holes (for the swingarm pivot bolt), when a collar/washer dropped from the front of the swingarm assembly.
I checked the swingarm and there was not another one like it, I also didn't have one in my bag of hardware from the disassembly. I scoured the manual for several hours and didn't see any part like this with a quantity of 1.
Just to give a description of the part, the inner diameter is the same size as the swingarm pivot bolt (but not big enough for the swingarm bushings to fit through). The outer diameter is roughly 1 inch and seems to fit well in the outer sides of the swingarm next to the bushings - acting as a separator for the swingarm and frame. The collar is roughly 1/4 - 1/3 inch thick, much more than a typical washer.
My best guess is that this is what the manual labels a 'collar' and fits between the bushings in the swingarm and the frame. I checked on bikebandit.com (2001 yz250n1) and this part is #9 on the diagram for 'rear arm'.
My question is, from somebody with more experience than me, am I correct in guessing what part this is and where it goes?
Also, is there no collar/washer between the inner swingarm/engine surface? Again, by looking at the manual and bikebandit.com schematic it appears that the only part is the oil seal which fits inside the swingarm.
Thanks greatly in advance for the help,
John