New rider concerned by sprocket nut problems!

[edc]

Hi all - 1st post!

I've been riding for just over two years problem free on my 2001 FZS600S and have now only just started 'customising' with heated grips etc. so am fairly inept when it comes to mechanics of the bike - but hopefully this forum will improve that!

I am somewhat concerned with this sprocket nut issue thingy where it appears that the wrong bits and pieces were used by Yamaha...  So how do I know if mine has a problem or not?!?!  I've recently had the spockets and chain replaced and the guys who did it didn't mention anything (Allens in Cambridge - a Yamaha dealer - what's happened to them I don't know!).

Is it only the early(ier) models?  Nothing in my service history indicates that any remedial work has been done...

Any help/comments welcome!

Cheers,

EdC

[Major Rant]

This is all from memory, no-doubt someone will be along in a minute to correct these lies.....
 
There was a problem up to about 2003 (ie all FZS600s) with the output shaft possibly being the wrong size. Everyone was (at the time) entitled to go to any yamaha dealer and get it checked at Mr Yamaha's expense - that offer SHOULD still be valid, but good luck getting anyone to recognise your rights after 9 years .
 
The solution was to measure the O/D of the output shaft and if it was below a certain number (17.5mm IIRC) then fit a new (different) sprocket, nut and washer.
This never happened to me cos mine (2000 FZS) was smack on 17.5mm - as measured by me with the nut still in place.
 
You could start by asking the folks that changed your sprocket if they used a new nut.... if they did then it would have been the 'good' sort.

[Captain Haddock]

If the old nut is 9mm thick replace it, the new nut is 12mm thick, it comes with a new tab washer for about £8

[marksfazer]

Had this problem last year
Have a look here on the old site, should answer most of your questions;


http://fazerowners.yuku.com/topic/5415/Lost-your-front-sprocket-and-washer?page=8#.Tx8Oo6XUO8B


Mark

[edc]

Cheers guys,

I'll have a look when I get the chance and see what (if anything) I have to do!

Thanks again.

[limax2]

From your post count Edc it looks like you could be fairly new here, so first off welcome to the site.

 
The solution was to measure the O/D of the output shaft and if it was below a certain number (17.5mm IIRC) then fit a new (different) sprocket, nut and washer.

Also to replace the gearbox output shaft if the thread was below that size.
 
The part number for the new 12mm thick nut complete with locking washer is 90891-10124. Always better to quote that number otherwise you could still be supplied with the old 9mm type by dealers.
I have measured the thread on three bikes and they were all round the 17.85mm mark and none have had a problem with the nut coming lose. A number of bikes were supplied under size and resulted in a stripped thread. Of course even with a good thread on the shaft it still has to be assembled correctly i.e. clean thread, loctite, and correct torque. Having said that Yamaha U.K. recommended 90Nm torque with the new nut but I have stuck with the 70Nm originally quoted and never had a problem.

[davec]

I wonder how many Fazers there are out there with the smaller sprocket nut on and have never had a problem?

[Fazerider]

@ Limax2
Is that right? My understanding was that the measurement of the shaft diameter was to determine whether it was still useable after loose nuts/sprockets had battered the thread, not that there was a problem with some of them being manufactured undersized.

[limax2]

"Fazerider". You could be right (but only maybe  ). I have not had this problem myself so am not speaking from personal experience. (Apart from a slight problem getting the new 12mm thick nut). I had always assumed there was a batch that were undersize from new. This because Yamaha where prepared to bear the cost of replacing the shaft(See below). However, if you are right, I'm surprised Yamaha were still prepared to cover it after several years and not say it was down to faulty fitting of replacement sprocket by the owner.
 
This is lifted from the old yuku site. Posted in August 2006 by Alistair.
The Inspection Notice (not a recall) that Yamaha issued to the Dealerships essentially says the following:

Any FZS600 Fazers model (1998-2003), regardless of whether it still in warranty or has been serviced officially in the Dealer channel can be inspected at any official Dealer.

Remove the existing nut and washer.
Measure the drive shaft OD of the threaded part (micrometer or vernier caliper).
If >= 17.5 mm -
clean threads and fit a new washer & nut with threadlock.
If < 17.5 mm -
the drive shaft must be replaced. (This work could take between 1 day to 2 weeks depending on Dealer workload).
 
This from old yuku site was posted in Jan2009 by dingus.
   i dont know if any1 is aware of this but yamaha will fit a new gearbox sprocket nut and washer free of charge to any fazer owner who,s had the problem of theres comeing loose. yamaha will also change the gearbox shaft if the threads are 17.5mm or under, this is also free of charge except for the engine oil.ive just had mine done . the warranty claim is open to all fazer owners ,the age, mileage and number of owners of the bike is irrelevant so ive been told.     

[Fazerider]

It just seemed a bit unlikely that there would be two reasons for the one problem, though I agree it's surprising Yamaha were prepared to replace not only the nut but the shaft, particularly after denying there was an issue for a couple of years after it came to light.
There are probably plenty of low mileage Fazers out there still with the original nut, looking back through my records I see I'd changed the chain and sprockets twice and covered 56,000 miles before mine was affected. And my local dealer still looks up the details on his microfiche and would order the old skinny nut if I didn't tell him the correct part number each time.

[HarryHornby]

WOW, so far so good, very impressed with Yamaha.
 
I've just phoned up the Faversham Bike Shop, Yamaha dealer (never used them but I've always heard good things) and explained my bike is an 02 reg, had it 2 years, no idea if the nut is correct or infact ok.
 
They've spoken to Yamaha head office, they have confirmed it can be done under warranty (not bad for 10 years later) and they will call me back to arrange getting it checked out......watch this space......

[CharlieDee]

Changed mine last night and loctite the bugger!! By the time I need a new sprocket on the front I will be on a thou!! 

[thom_1991]

I wonder how many Fazers there are out there with the smaller sprocket nut on and have never had a problem?

Mine but i've ordered the new one for peace of mind.

[Tefer]

My front sprocket is done up tighter than my wallet


Breaker bar and still not coming off, any suggestions or i'll have to cut it free!

[limax2]

My front sprocket is done up tighter than my wallet


Breaker bar and still not coming off, any suggestions or i'll have to cut it free!

I don't know if anyone has ever damaged the gearbox by using excessive force, but for the cost of a new nut I would be inclined to split it if it's that tight. If it's held with Loctite or similar (as it should be) heating it up will break down the Loctite but you then risk damaging the oil seal.

[edc]

Should probably say that I checked and low and behold - it was the wrong nut.

Ordered the right one from Wheel-fit and replaced with some help from my glamorous assistant ('The Mrs') holding the brake on!

Thanks for all the advice!

EdC