Front sprocket - again!!

[Newgolddream]

Oh dear, just changed rear tyre, chain and both sprockets. All fine apart from the (common I now see) front sprocket nut, washer, shaft problem. Nut = knackered; washer = knackered; thread on shaft = knackered.
Has anyone had any recent dealings with Yamaha regarding this? Will they do a free shaft replacement on a 1999, 30K FZS600?
I will contact them myself tomorrow but don't want to get fobbed-off by anyone. If they are not doing this repair (to parts not fit for purpose) is there another quick fix i.e cut new thread onto shaft and source a different nut.
 
 
 
 

[Fazerider]

I'd be a bit surprised if Yamaha still feel obliged to pay for replacement... I'd agree they ought to, but realistically not many manufacturers (of anything) will undertake warranty repairs a decade or so after the initial sale.
Assuming they don't want to play ball, you can:
a) pay someone to do it
b) do it yourself
c) buy a replacement engine and swap it
or
d) simply weld the nut onto the shaft.
I did that on my original engine since I couldn't be bothered with the hassle of losing the bike while the shaft was replaced under warranty. Sounds brutal, but it's cheap and can be done several times, just cut through the weld with an angle grinder when it's time to replace the chain and sprockets.

[Newgolddream]

Thanks for the reply. That's pretty much what I thought, just wondered if anyone had recent dealings with yamaha on the subject. There's about one turn of good thread on the shaft to get the nut started, after that it is flattened off. I think I'll re-cut the thread to get the nut on and then weld it. One spot sufficient or two for good measure?

[Fazerider]

If the thread is knackered it's hard to get the nut on tight, this means the sprocket will have a little side to side play. I found just tacking the nut on wasn't enough to withstand the rattle for more than a few hundred miles. Being a bit more generous with the welding rod did the trick.





I know I took a pic just after doing it once, but this one is all I can find now. Rust means it's not very clear now, but you may be able to make out that the nut is about 80% welded to the shaft.
Of course, the fact that mine didn't hold when I only did a couple of small welds may be down to my crappy technique.

[Newgolddream]

Info and pic much appreciated. I'm off to persuade neighbour, who has welding kit, that he could do this for a beer or two!  

[Captain Haddock]

Try and keep wels spatter from sticking to the chain, it'll soon wear the sprockets out again, good luck with it.

[Fazerider]

Try and keep wels spatter from sticking to the chain, it'll soon wear the sprockets out again, good luck with it.

A very good point.
Weld before fitting a new chain or, if the existing one still has life in it, get it off the sprocket, pulled back against the swingarm pivot and shielded with an offcut of thin plywood. Spatter is bad for O-rings!

[oldmotherfoccer]

Spatter is bad for O-rings!

fnarrrr fnarrrr i knew there was a reason that bottom sex was bad 

[Captain Haddock]

Back on the sprocket nut issue again, has anyone had it happen while still on the original factory fitted chain and sprockets or is it only after replacement that it goes tit up?
I have to admit to never using a torque wrench on a sprocket nut before, in fact usually swinging on the biggest bar to hand while stomping on the rear brake (and I'm supposed to be an aircraft grease  monkey).

[Fazerider]

It only happened on mine after changing the C&S. Maybe that plastic composition on the OE sprocket reduces vibration enough to make the difference. (I did enquire about a genuine Yamaha front sprocket at my dealer... that alone was about the same price as an aftermarket chain and sprocket set, so I didn't pursue that theory!)

[Fazer Jake]

I'll be changing the front sprocket and rear on my 2003 fazer very soon, bikes only done 14k miles i'm pretty sure its still the original.

Nut and threads look fine.

What do i need to look out for/any additional fits?

[Captain Haddock]

Check the total thickness of the nut, if 9mm change it, if 12mm leave it, the nut/washer kit is about £8, p/n is 90891-10124, it's cheaper than finding out after it's focced the gearshaft.

[Newgolddream]

GOOD NEWS! Before taking rod (welding) in hand, and risking spatter on my o-rings, I decided to give those nice people at Yamaha a ring. Turns out a mod should have been carried out during a service at some point and, assuming affected parts were out of tolerance, this - and any resulting repair work - could be done now foc.
I got the bike into a local dealers (Skellerns - Cheltenham - seem very efficient) who took measurements of the parts, sent them off to Yamaha, next day Yamaha came back saying yes they will foot the bill.
So, if anyone is still suffering with this problem, get your local dealer to check the bikes history. It's much better than risking spatter!

[Fazerider]

In the words of Monty Burns, "Excellent!".
What a decent company.
I'd buy another bike from them... if they hadn't made such a damn fine one that I don't want to change.

[limax2]

Well done Newgolddream, I'm totally gob smacked that you got such a fantastic result, well done again  .
 

[Captain Haddock]

I'm surprised they are still happy to foot the bill on a 12 year old bike but very good news indeed, is it because the service history checks out? I have no service history with mine so I assume it's either not been done or not done at a dealership so I'd probably be stuffed.

[Newgolddream]

I was surprised myself and feel very fortunate that Yamaha agreed to carry this work out on a bike of this age.
When the nice lady at Skellerns looked into the bikes history (only very early stuff) there was no record of any modification to this area. She went on to say that, in their experience, as long as the parts involved were 'out of tolerance' then, generally, yamaha would agree to the work. All parts are shipped from Holland - so a couple of days wait there - then about 12 hours labour.
Can't wait to get the old girl back now. Fed-up with sitting motionless in queues of traffic every day.