Primary Chain Plunger Pad Separation

Edfury828

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After a long winter of putting off tearing into my primary (due to endless priorities of life) to change out my Stator and Rotor (with crunchy harness and exposed copper wire), I finally got to it last night. It was then that I found to my surprise, one of the rubber pads of my new Primary Chain Tensioner Plunger had separated and was lying in the bottom of the case. This left the steel backing of the plunger to push against my chain with some amount of wear resulting. The plunger backing plate was not too worn, but did show some wear where it was in contact with the chain. I did not inspect the chain too closely only thinking that it should still function fine as a chain.



Since then, it has occurred to me that the replacement plungers pad may self-destruct from the newly created wear pattern on the contact surface of the chain? I think the only way to be safe is to replace the primary chain, which had already been replaced by the PO before I bought the bike. I’ll probably just have to take my lumps and move on, but I did buy the plungers new from AN two years ago and have only ridden the bike for about 250 miles.

I can’t imagine what would make the pad separate from the plunger? Is this something that is known to happen on
MK-III’s? Could there have been a batch of plungers that were defective, maybe with bad glue? It could be a long time before I am able to trust my self-adjuster again!

I also discovered that my Cross Shaft (for shifting) was pretty worn and pitted at the seal surface. It doesn’t seem to be leaking, but I should probably replace the shaft and seal as well.

I’ve sent an email to AN to see what, if any guarantee there may be at this point. More than anything, I am just discouraged about the down time. That and general reliability. I was really hoping to get the bike running and, dare I say, actually find it to be ride-able for this summer. I know it could be way worse, but WTF?
 

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  • Primary Chain Plunger Pad Separation
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Same experience with my MK111 latest order from AN . Both plungers had separating pads from the metal surface , AN had no comment when I said order received ... But the pads are slowly lifting off . After thinking /musing about what could have caused this , it's likely the glue used dried out or failed , being not up to the job. It doesn't look like the pads were hot formed to the curved surface ? Anyways I cleaned the surfaces with brake spray , mixed up some fresh epoxy and gave both a try . Good so far .
Wonder what the black slipper material is anyways .. as it wears the tiny black dust circulates through the primary until next oil change .
 
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