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Another Loose Sprocket Nut - Printable Version

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Another Loose Sprocket Nut - Guest - 16-06-2007

<!--quoteo(post=44243:date=Fri 15th Jun 2007, 11:02 PM:name=Toneski)-->QUOTE(Toneski @ Fri 15th Jun 2007, 11:02 PM) <{POST_SNAPBACK}><!--quotec-->sorry GG, buts thats exactly whats happened, its pulled over the thread, i can see that from the damage to the nut
trying to find where i put the damaged nut so i can post a pic

there does seem to be less movement on the splines with genuine yammie sprocket<!--QuoteEnd--><!--QuoteEEnd-->


In that case Toneski, you must have had a faulty nut with an oversize effective thread dia &/or core dia, or your shaft has a thread with an undersize effective thread dia, &/or undersize maj dia.

A correctly manufactured shaft & nut will never jump threads when torqued

I've worked in machine shops producing threads as Quality Control / Assurance.
Oversize core dia on the nut allows low torque thread stripping, as does a truncated thread on the shaft.
I have never, in twenty years of engineering, ever heard of a nut jumping threads after it was torqued up. When loose yes, but not when tight.


<!--quoteo(post=44273:date=Sat 16th Jun 2007, 11:22 AM:name=Toneski)-->QUOTE(Toneski @ Sat 16th Jun 2007, 11:22 AM) <{POST_SNAPBACK}><!--quotec-->is it possible the splines can wear over time?<!--QuoteEnd--><!--QuoteEEnd-->


Yes - I had an X7, where the sprocket wasn't clamped tight, merely held on by a splined washer that bolted to the sprocket.
The sprocket sat 'loose' on the output shaft, but could come off due the splined washer which was 1/2 spline width rotated

It used keep ripping the splines out of sprockets - I replaced the output shaft and it nver did it again. The splines on the shaft were worn allow it to destroy the sprocket splines

<!--quoteo(post=44318:date=Sat 16th Jun 2007, 06:22 PM:name=ChrisG)-->QUOTE(ChrisG @ Sat 16th Jun 2007, 06:22 PM) <{POST_SNAPBACK}><!--quotec-->Not convinced about this sprocket thickness isue but going for a Yam one just in case. Sprocket sits on the splines and there's a section of shaft behind, so the shoulder it sits against is probably too small to have another washer on.

[Image: output%20shaft.jpg]

I had 2 washers between the sprocket and the nut though so that should have the same effect as a thicker sprocket.

I've put the old sprocket back on for the time being with a new nut and locktight on the nut only. Should have the new chain and sprockets by next weekend which should be less than 700 miles away, I'll then use the locktight on the sprocket as well and accept that I'll need a bearing puller to get it off again.

The old chain is a DID X-ring has been on for 25-30,000 miles (with a scott oiler)<!--QuoteEnd--><!--QuoteEEnd-->

<!--quoteo(post=44289:date=Sat 16th Jun 2007, 01:29 PM:name=ChrisG)-->QUOTE(ChrisG @ Sat 16th Jun 2007, 01:29 PM) <{POST_SNAPBACK}><!--quotec-->Yikes, genuine yam front sprocket is nearly £50 compared to less than a tenner for a pattern one, and it's going to take a week as Fowlers haven't got any in stock.

Oh well, it's on order and my x-ring chain and pattern rear sprocket are on their way form M&P<!--QuoteEnd--><!--QuoteEEnd-->
I've never had an issue with JT sprockets

You will need a 3 legged puller to get it off after loctiting
A good one is available from Machine mart for about £10 (its the one I use on my DRZ)
http://www.machinemart.co.uk/shop/product/...le-150mm-puller

<!--quoteo(post=44286:date=Sat 16th Jun 2007, 12:32 PM:name=ChrisG)-->QUOTE(ChrisG @ Sat 16th Jun 2007, 12:32 PM) <{POST_SNAPBACK}><!--quotec-->Hmmm, Fowlers will only do genuine Yamaha parts, is the X-ring going to be noticable better than the genuine one?<!--QuoteEnd--><!--QuoteEEnd-->

X ring chains are a noticeable improvement over ordinary O rings for longevity - std will be an O-Ring. DID make the best chains
I had 30K miles out of an X ring, using just spray on lube

<!--quoteo(post=44270:date=Sat 16th Jun 2007, 10:33 AM:name=ChrisG)-->QUOTE(ChrisG @ Sat 16th Jun 2007, 10:33 AM) <{POST_SNAPBACK}><!--quotec-->edit: almost forgot, how tight should the fronty sprocket fit on the splines? Mine can rotate by a noticable amount, which could mean it allows it to slide around and wear.<!--QuoteEnd--><!--QuoteEEnd-->

Should be a sliding fit - with the minimalist amount of play. If you've got some rocking then your output shaft splines are worn
The locitite will hold it tight though once it has gone off - the Loctite cures to form a Thermoset plastic
Allow 24hrs for it to cure fully

Another Loose Sprocket Nut - wicklamulla - 16-06-2007

wood "Jeg Peg with the extra leg" benefit from one of them 3 legged pullers i wonder ?

Another Loose Sprocket Nut - ChrisG - 17-06-2007

I seem to have developed what should probably be referred to as the "Toneski syndrome", I've just checked my sprocket nut 3 times in 100 miles [Image: rolleyes.gif]

Another Loose Sprocket Nut - TonyDevil - 18-06-2007

[Image: rotflmmfao.gif]
even i'm only checking once a day or at each fill up [Image: rolleyes.gif]

Another Loose Sprocket Nut - ChrisG - 18-06-2007

It's still tight after 220 miles so I'm gonna trust it to last until Saturday when I'll hopefully have the new chain and sprockets

Another Loose Sprocket Nut - ChrisG - 20-06-2007

Can someone please confirm the chain size? M&P have sent me a 525x114 and I want to make sure it's the right one before I cut the old one off at the weekend.

Another Loose Sprocket Nut - Guest - 20-06-2007

<!--quoteo(post=44689:date=Wed 20th Jun 2007, 07:35 AM:name=ChrisG)-->QUOTE(ChrisG @ Wed 20th Jun 2007, 07:35 AM) <{POST_SNAPBACK}><!--quotec-->Can someone please confirm the chain size? M&P have sent me a 525x114 and I want to make sure it's the right one before I cut the old one off at the weekend.<!--QuoteEnd--><!--QuoteEEnd-->


thats correct for std size sprockets on a mkI

from the JT sprockets website:-
Front Sprocket: JTF 520.16
Rear Sprocket: JTR 867.44
Recommended Chain: : 525 / 114

Another Loose Sprocket Nut - dapleb - 20-06-2007

http://www.carpe-tdm.net/ipb/index.php?showtopic=4421

Another Loose Sprocket Nut - TonyDevil - 20-06-2007

and for those with a haynes book of lies the info is on page 6.2 under the "Final drive chain" section

Another Loose Sprocket Nut - ChrisG - 20-06-2007

Cheers gents. I'd mislaid my Haynes but now found it in one of my panniers

Another Loose Sprocket Nut - ChrisG - 22-06-2007

When I put it back together the other week I put on a new nut and used locktight on the nut, but didn't put it on the sprocket as I'd ordered a new chain and sprockets.

New sprocket arrived today, and I've done about 500 miles in meantime. Just dismantled it and the sodding sprocket nut was slightly loose again [Image: ranting.gif] I've now put in the new sprocket with locktight all over the splines (new one fits a lot tighter on the splines than the old one suggesting a bit of wear there too) and another new nut with locktight all over the thread.

Mate of mine suggested maybe the locktight gets attacked by the oil, which I guess is a possibility. Any ideas?

Unfortunatly I managed to burr one of the rear sprocket nuts quite badly getting the damn things off, hoping Camberley Autofactors might be able to supply me with some more otherwise it's a trip up to AHC tomorrow.

Dremmel makes light work of taking the old chain off though.

Another Loose Sprocket Nut - Guest - 22-06-2007

<!--quoteo(post=44994:date=Fri 22nd Jun 2007, 08:52 PM:name=ChrisG)-->QUOTE(ChrisG @ Fri 22nd Jun 2007, 08:52 PM) <{POST_SNAPBACK}><!--quotec-->When I put it back together the other week I put on a new nut and used locktight on the nut, but didn't put it on the sprocket as I'd ordered a new chain and sprockets.

New sprocket arrived today, and I've done about 500 miles in meantime. Just dismantled it and the sodding sprocket nut was slightly loose again [Image: ranting.gif]<!--QuoteEnd--><!--QuoteEEnd-->
What variety of Locktite are you using?

Another Loose Sprocket Nut - TonyDevil - 23-06-2007

ouch mate [Image: sad.gif]

he's using 638 the permenant stuff

i cleaned mine up before using locktite, bit of fairing liquid does the trick [Image: wink.gif]

Another Loose Sprocket Nut - ChrisG - 23-06-2007

<!--quoteo(post=45018:date=Sat 23rd Jun 2007, 01:01 AM:name=Toneski)-->QUOTE(Toneski @ Sat 23rd Jun 2007, 01:01 AM) <{POST_SNAPBACK}><!--quotec-->i cleaned mine up before using locktite, bit of fairing liquid does the trick [Image: wink.gif]<!--QuoteEnd--><!--QuoteEEnd-->

So did I, with clutch and brake cleaner.


Table at the bottom of page 2 suggests it could eventually have a problem with scott-oil but it'll take a while. By comparison they sell 243 as being oil resistant but it doesn't seem to do a lot better on the data sheets

Another Loose Sprocket Nut - Guest - 23-06-2007

<!--quoteo(post=44994:date=Fri 22nd Jun 2007, 07:52 PM:name=ChrisG)-->QUOTE(ChrisG @ Fri 22nd Jun 2007, 07:52 PM) <{POST_SNAPBACK}><!--quotec-->When I put it back together the other week I put on a new nut and used locktight on the nut, but didn't put it on the sprocket as I'd ordered a new chain and sprockets.

New sprocket arrived today, and I've done about 500 miles in meantime. Just dismantled it and the sodding sprocket nut was slightly loose again [Image: ranting.gif] I've now put in the new sprocket with locktight all over the splines (new one fits a lot tighter on the splines than the old one suggesting a bit of wear there too) and another new nut with locktight all over the thread.

<!--coloro:#FF0000--><!--/coloro-->Mate of mine suggested maybe the locktight gets attacked by the oil, which I guess is a possibility. Any ideas?<!--colorc-->
<!--/colorc-->

Unfortunatly I managed to burr one of the rear sprocket nuts quite badly getting the damn things off, hoping Camberley Autofactors might be able to supply me with some more otherwise it's a trip up to AHC tomorrow.

Dremmel makes light work of taking the old chain off though.<!--QuoteEnd--><!--QuoteEEnd-->


The loctite will be ok once cured.
Chain lube etc can't get into the splines etc with the nut on and torqued up.


Make sure you leave it 24hrs to ensure it is fully cured.

Loctite do 603, which is oil resistant, but isn't as good at filling larger gaps.
The 638 is design to wick into the gaps between splined shafts.

Loctite 243 isn't strong enough. It will not work. Trust me, you will still have a loose nut after time.

there is also '680' as well if you can't get 638.

Cleanliness is paramount. Use brake cleaner or contact cleaner to ensure the shaft and nut are spotlessly clean & oil free. Remove any rust with fine wet & dry, and clean again with brake cleaner or contsct cleaner.

Another Loose Sprocket Nut - ChrisG - 23-06-2007

I attacked it with some brake cleaner and a toothbrush.

Gold chain looks pretty [Image: good.gif] and I borrowed a chain riviting tool of a mate which made life so much easier than last time when I used a ballpien hammer

Another Loose Sprocket Nut - TonyDevil - 23-06-2007

<!--quoteo(post=45063:date=Sat 23rd Jun 2007, 01:17 PM:name=ChrisG)-->QUOTE(ChrisG @ Sat 23rd Jun 2007, 01:17 PM) <{POST_SNAPBACK}><!--quotec-->Gold chain looks pretty [Image: good.gif] and I borrowed a chain riviting tool of a mate which made life so much easier than last time when I used a ballpien hammer<!--QuoteEnd--><!--QuoteEEnd-->
doh, meant to message you t'other day bought that, i have one too if anyone local needs to borrow

Another Loose Sprocket Nut - wicklamulla - 16-07-2007

well PK, Spongey and meself discussed the front sprocket nut problems on MKI's and XTZ 750's after i proudly proclaimed that i had reused my front nut and tab washer 4 times with great success and the nut still looks perfect, i refitted me front sprocket yesterday and decided to use a brand new nut and washer just to be safe !! PK mentioned that when the nut is torqued up on a MKI there is usually some threads showing on the output shaft ?? is this accurate Tonski and udders ?? well heres a pics of mine fully torqued up past the 70Nm limit with no thread showing (i am using a genuine yam fr. sprocket, nut and tab washer) i also took some measurements & pics of the outputshafts on both my 1999 enjuns if anyone wants them lemme know.

[Image: DSCN2286.jpg]

Another Loose Sprocket Nut - TonyDevil - 16-07-2007

<!--quoteo(post=47461:date=Mon 16th Jul 2007, 03:23 AM:name=wicklamulla)-->QUOTE(wicklamulla @ Mon 16th Jul 2007, 03:23 AM) <{POST_SNAPBACK}><!--quotec-->PK mentioned that when the nut is torqued up on a MKI there is usually some threads showing on the output shaft ?? is this accurate Tonski and udders ?? well heres a pics of mine fully torqued up past the 70Nm limit with no thread showing (i am using a genuine yam fr. sprocket, nut and tab washer)<!--QuoteEnd--><!--QuoteEEnd-->
yes, there is approx 2-3mm showing on the mk1
same on the Super Tenere (1991 750 mk1 engine)
on the TRX its almost flush (1997 850 mk2 engine)

dont over torque, i think thats how mine got forked, proper forked

Another Loose Sprocket Nut - wicklamulla - 16-07-2007

ya mines almost flush, looks like the outputshafts are different or the nuts/sprockets we are using.