Has your front sprocket ever come off? (on its own?)

[heyblue46]

Hi all,
this was strange to me and leaves me with questions.
First off... 1980 1100et w/42000 miles. Daily rider.

Noticed a new strange noise while going down the road. Sounded like a high pitched whine much like the sound of metal as its being turned on some kind of machine shop tool. You know the sound, and pitch changed slightly with rpm. Rode for a couple of days trying to place it and figure out what it was. Nothing. Noticed my chain needed adjusting so I did that.

Out of the blue next day when i rolled off the throttle I heard this very loud screeching/rattling sound that scared the crap out of me just before i stopped at a stop sign. Sounded like i was draging sheet metal on a rough paved road. Got off, looked it over, touching/moving/shaking to see if something was loose. Nothing. During the day, while driving VERY cautiously I heard this noise about 3 more times and finally decided something was VERY wrong with my front sprocket.

Pulled the cover and noticed what looked like a fine string wrapped around the shaft. I pulled all that off and held my magnetic tool finder up to it. Yep, its metal! There was also a big pile of gunk and grease in the bottom of the cover. In the grease was a large diameter thick washer, my lock washer and nut that holds the sprocket on! Replaced everything locking it down good and tight and everything seems to work ok,..... except now it rides very rough. I'm assuming my front sprocket and chain are out of wack. Chain was about at the end of its life anyway and I was about to replace it.

Long post for this question.. what is that large diameter thick washer? I would say it's at least 1/4" thick and maybe more. Is this normal or is it a possibly a spacer to allow a 530 chain to be used? All my clymer shows here is the very thin lock washer and nut.
Also, i cant really see where the thin metal string might have been shaved off of. No real ruts or cuts in the shaft that I can notice. Sprocket seems to fit nice and snug with no perceivable play as it is slid onto the shaft.

Sorry for such a long post and thanks for any comments.

Steve

[chef1366]

Make sure the lock lock tab washer enters the splines just a tad. If it doesn't there might as well not be one. My bike came with a lock nut which turned out to be useless because I lost my sprocket TWICE! What a heart wrenching feeling and terrible thoughts of transmission work.

Also make sure you didn't lose the inner spacer.

[kingofvenus]

I have the reverse problem, mine will not come off. Brand new big dollar impact won't even budge it. I think I'm going to have to pull the motor out and split the cases.

[bradleymaynar]

The washer, #48 in chef's diagram, should be folded over the nut, #47. The thread is designed to tighten the nut on the output shaft when the bike is under accelleration. The folding of the washer is supposed to prevent the nut from backing off.

As for the metal shavings, check the case cover over the front sprocket. If it's not from there, it could be from the chain guard, if it's metal.

Brad bt

[txironhead]

If your bike is currently running a 530 chain and it originally came with the 630, then the thick washer is probably the spacer needed to run the converted front sprocket. It also would not show up in the manual, because the manual only shows the 630 chain. I believe that the spacer goes on the outside of the sprocket to allow the nut to tighten properly. If the sprocket is allowed to slide back and forth, it would make quite a racket and possibly damage something.

And to the person who can't get their sprocket off, have you tried heating the nut? It may damage the shaft seal, but that can be replaced, and tearing the cases apart is a bit drastic. I'd also recommend soaking it in Corrosion X or PB Blaster for about a week.