What's the function of the rubber washer between the nut that preloads the steering stem bearings and the nut that the triple sits on top of?
To keep dust and debris out of the bearing area. May even help with water intrusion as well. Sent from my iPhone using Tapatalk
It's soft rubber so if you tighten the upper nut too much it distorts it. Bike is a S1000rr although I've seen it on other bikes as well.
Increasing drag on loosening...that's all I got. Possibly so the 2 fasteners don't chem-weld ? Just guesses...but it has to have a function .. Singular use like a crush washer.
The one on my bike isn't a lockwasher though, it's just a rubber washer, here's a pic, it's durometer is softer than a tire
I believe this is how my 04/06 R1 is, can be very annoying because every few thousand miles the lower but will work it’s way loose a bit. I get in there and snug it back up as close as I can get to specification but it seems to end up doing it again.
Looks to me like you have a tabbed washer that keys the two nuts together. The rubber washer gives you some adjustment "squish" which allows you to line up the grooves in the nuts. Shouldn't there be a larger plastic "cover" there also to help seal that area from water?
That's what I think happened, my '04 R1 has the same setup as you mentioned There is a tabbed washer and and no plastic cover, or at least not one when I bought the bike from the previous owner The squish you mentioned makes the most sense but my bearings had to be tightened up about a half turn recently
My 600rr has the rubber and a keyed washer to lock em in place. That may have been my fz1 actually I can't remember. I think it's to help lock em in place.
The rubber washer keeps the lock rings separated. The gap prevents the bearing preload from tightening up when the top crown nut is torqued down.