Rear sprockets nut & swingarm chain protector
 

Hello,

I started some maintenance today. Wanted to change chain+both sprockets, and take the swingarm out to have a good look at it and check bearings (+ linkage bearing).

First "easy" issue: The swingarm protector has two little (7mm and 3mm) holes on the underside, where the chain hits it. The swingarm itself starts to wear at the same location, but it is really light.
So i'm looking to buy a new one, can someone please confirm 11D-F2151-00-00 is the correct part number? Looks so on different website part diagram, but it's labelled as "seal guard" ?!
Or if there is a good trick to fix it for cheap, it's only wearing in a few location and it's just plastic anyway, right?


Second issue: one nut holding the rear sprocket don't go out. It's spinning but it seems that either the nut thread or the screw thread is f.. up. I did not know you could damage the threads when unscrewing, or was it like that from the factory (as far as i know this is the stock sprocket i'm trying to remove).
Anyway, what's the best way to get it out? As the screw itself seems to sit in a threaded hole in the sprocket carrier, I'm considering piercing the screw, tap the hole and use this to get the whole screw out. Not sure if it will work as i guess the sprocket carrier screw is well "locked" somehow (loctite or what). Not sure either if it's better to get it out to the outside or to the inside of the carrier (both should work)?

Thanks

This is the correct part - although you've got one too many 00s! ;)

The studs are screwed into the sprocket carrier. The sprocket carrier is a crappy cast alloy and the threads are just cut into it. I am 100% sure that the stud is at fault and is spinning in the carrier. It won't be the nut if it's a stock one or the thread on the stud as they are both steel.

Persanally I'd just take a cutting disc/grinder to the nut and cut it off if you're discarding the sprocket. The remaining bit of stud will be easy to remove if the threads in the sprocket carrier are knackered. You will need to insert a Helicoil in the offending hole and buy a new stud/nut.

Thanks for the answer.

I can see the stud from the inside or the outside of the carrier, and it is not spinning.
I think you're right and the simple way is to cut the nut.

It hasn't got aftermarket aluminium nuts fitted has it by any chance?

I don't know.. the nuts look good old stock to me, it seems they were never removed. I bough the bike used but have a good history of maintenance and parts bought by the previous owners. The nuts were pretty hard to remove and some got easely rounded in the process, so it may be aluminium?

Well anyway i cut the nut and could remove the sprocket. The stud took quite a beating, but after removing the broken threads of the nut, i can tighten and remove another nut on the stud (there is a hard point at the beginning but then it goes on ok).

Ok so ready to order the swing arm guard and nuts. Should i order yamaha nuts at 3€/nut, or is it some standard stuff i can find elsewhere :), like any self tightening steel M12 bolts?

thanks again

I somehow don't believe that they were the OE steel nuts if they rounded that easily and one stripped its threads? :102:

Any flanged self-locking steel nuts will do the job, just make sure they are decent quality. You pay for what you get when it comes to fasteners!