Why don't the sump cover and starter gears cover use lock washers?

xjwmx

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Is there a reason? Does the compressed gasket act as a lock washer? Or would a lock washer continue to compress the gasket and eventually kill it?
 
From what I’ve read... these bikes vibrate pretty good. If it has a spring washer then no threadlocking compound. If not? Use some locktite. I changed the battery ground from the frame motor mount to the engine case bolt and was just a bolt with a plate washer and it had a thread locking compound on it.
 
My engine doesn't have any accessories to cover :) But seems like nothing with a gasket that comes to mind takes lock washers. Had starter gears cover seeping after a couple years. Noticed a couple of its bolts were looser than they started out. Handmade gasket using Fel-Pro rubberized paper might have lost resilience or something and quit pushing back on the bolt heads.
 
^Good point, plus aluminum compresses and doesn't hold tension. You sometimes see a lock washer over a flat washer, but have read that doesn't make sense, since the flat washer can turn, so the lock washer bite doesn't accomplish anything.
 
Maybe because a steel lock washer would chew up the alloy, and those bolts are removed and put back in more than most other fasteners on the bike = continuous, repeated, alloy chewing.

Scott
that is why you always see a flat steel washer between the lock and alloy surface .we were taught that at trade school
 
I've wondered about this as well, especially for the points/advance and alternator covers. No gaskets there, but no lock washers either, and I've never had them come loose. One thing I do is swap out the 10mm long screws on the alternator cover for longer ones. Seems Yamaha cheaped out here. Those 10mm long screws don't even engage all the available threads .....

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