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Loose front sprocket nut...
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28-09-21, 11:27 PM
(13-09-21, 08:56 PM)Captain Haddock link Wrote: If anyone needs the new nut and tab washer kit I have one sitting right beside me, I sold my 600 years ago now, kit no. is 90891-10124.Anyone near south cambs. is welcome to collect it or cover postage.Hello mate, have you still got this nut and tab washer kit? 
Personal view
The sprocket nut is there to stop the sprocket sliding off the output shaft. It doesn’t need to tighten flush with the sprocket to do this. The output shaft is the fault on some of the fazers. The grooves in some output shafts are cut a slightly too wide. This allows the sprocket to move backwards and forwards on the shaft when placed under load or off load. Because the nut is tight against the sprocket it continually rotates slightly on the threads… wearing them out. The answer in my opinion is grind down the flange on the sprocket nut so that when it tightens on the shaft it is simply flush with the sprocket but does not tighten against it…. And put some grease on the sprocket to further ease the junction between the nut and sprocket. Therefore there is insufficient ‘grip’ between the sprocket and the nut to allow the sprocket to turn the nut. In essence you want to tighten the nut up on the output shaft but not tighten it up against the sprocket.  (30-09-21, 01:47 PM)Paul link Wrote: Personal view Err no, on all counts. The sprockets MUST not move in any direction or you get what's known as chatter, which is exactly what this issue was/is. I've changed many back in the day, some the nut was still locked up tight, others there's was no nut left, the sprocket being held on by the chain tension. The issue is the nut recess on some earlier nuts and the thread wasn't deep enough to lock against the sprocket and the layshaft shoulder when torqued up. This enabled the sprocket to chatter and wear the nut facing, which in turn destroyed the nut due to it being softer than both the lay shaft and the sprocket.
Later
30-09-21, 08:31 PM
Just for interest this is a drawing I did and posted long ago on the sprocket nut topic. I've no information on the manufacturing tolerances but it will effect the clearances to a lesser or greater degree.
[smg id=1964] 
01-10-21, 09:52 AM
(28-09-21, 11:27 PM)StreetFzr link Wrote: [quote author=Captain Haddock link=topic=27005.msg327098#msg327098 date=1631562998]Hello mate, have you still got this nut and tab washer kit? [/quote] PM sent.
Save the planet...It's the only one with beer!
01-10-21, 01:26 PM
To Gnasher
The reason why the threads wear out on the output shaft and the nut, is in my opinion due to sprocket chatter. The reason why you get sprocket chatter is because the sprocket and output shaft aren't a tight fit. If you can hand push the sprocket onto the output shaft, you'll likely get some sprocket chatter. In essence if you have to tap it on with hammer you should be o.k., but if you can push it on by hand then you could end up with problems. I put 110,000 miles on my last Fazer, and changed the drive sprocket several times, fortunately I had to tap it on with a hammer, and thus never had problems. A guy I knew who also had a Fazer, had the sprocket nut issue, and he found his sprocket was a push fit onto the output shaft.... it didn't need tapping on.
Oh no not another DIY chap with a theory :rolleyes
(01-10-21, 01:26 PM)Paul link Wrote: The reason why the threads wear out on the output shaft and the nut, is in my opinion due to sprocket chatter. Yep, I told you that  (01-10-21, 01:26 PM)Paul link Wrote: The reason why you get sprocket chatter is because the sprocket and output shaft aren't a tight fit. Nope :rolleyes see my last. The sprocket must be a loose push fit to allow for shaft expansion and easy extraction. If not the drive splines will become damaged i.e. burred and you'll struggle to get it off without a puller or a your No1 tool a hammer.  (01-10-21, 01:26 PM)Paul link Wrote: If you can hand push the sprocket onto the output shaft, you'll likely get some sprocket chatter. Nope. Not if sprocket is pushed up against the lay shaft shoulder by the lock nut, once it's torqued. (01-10-21, 01:26 PM)Paul link Wrote: In essence if you have to tap it on with hammer you should be o.k., but if you can push it on by hand then you could end up with problems. Nope, I've worked on bikes for 30yrs and still do. I've never put a front sprocket on any make of bike with a hammer, total DIY crap :rolleyes (01-10-21, 01:26 PM)Paul link Wrote: I put 110,000 miles on my last Fazer, and changed the drive sprocket several times, fortunately I had to tap it on with a hammer, and thus never had problems. Good for you  Shame you didn't tell Yamaha then, save them issuing a workshop bulletin after their experts found the issue. Oh course they were wrong all the time, Paul had the answer :rollin :rollin :rollin Your lay shaft splines are most likely burred :rolleyes Not all were effected. (01-10-21, 01:26 PM)Paul link Wrote: A guy I knew who also had a Fazer, had the sprocket nut issue, and he found his sprocket was a push fit onto the output shaft.... it didn't need tapping on. See above all front sprockets are loose push fit. This is all very old and very well documented. If you wish to have these half barked theories, I'd keep them to yourself, bloody funny though :lol :lol
Later
01-10-21, 07:36 PM
:lol :lol :lol got me popcorn ready :lurk :lurk :lurk :lurk
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