Chain wear - help please [Archive]

chasio

17th May 2009, 17:36

About 500kms ago I had a new DID O-ring chain and JT sprockets fitted on my XF650 Freewind. I did this because the chain was worn unevenly (very variable chain tension) and the front sprocket was pretty hooked so I thought I'd do the lot.

I was inspecting the chain and checking tension yesterday.

The Scottoiler with single sided delivery seems to be keeping the chain correctly lubed. And the lube on the chain when fitted should have been looking after it that far, shouldn't it?

But the chain is already showing signs of uneven tension. That surprises me after so few kms. So I'm wondering why.

The wheel alignment seems OK by eye (I'm not trusting the swingarm marks much but they are about level as it happens) and I also don't know if alignment issues would cause uneven wear anyway...

I'm hoping it doesn't mean damage further up the drivetrain.

What should I be checking for?

Cheers - Chasio

chasio

21st May 2009, 20:47

OK the full story is here. (http://www.kiwibiker.co.nz/forums/showthread.php?t=99469) No replies so I thought I'd try posting in here (apologies if cross posting winds anyone up).

Basically the chain on my XF650 Freewind (essentially a DR650 drivetrain I believe) is showing signs of uneven tension after only 500kms. I will be pissed off if this is because it is wearing quickly and unevenly and my $200 chain goes south after only a few thousand kms on brand new sprockets.

Is this normal? I'm guessing not but maybe I'm being a nana.

Alignment, cleaning and lubrication all look good to me. Any suggestions?

Cheers for any input.

Chasio

pete376403

21st May 2009, 21:36

Are the sprockets concentric on the shaft (front) or wheel (rear)

You could check this by raising the back off the deck and rotate the wheel while holding a pointer so it is almost touching the sprocket tips - if there is any eccentricity you should see it quickly. Do the same with the front sprocket.

Apart from that - take it back to the supplier and let them resolve it.

puddytat

21st May 2009, 21:36

It may be slop between the sprocket bolts & sprocket holes....I put a thin strip of an aluminium can round the bolts to take up the slop & so the sprocket is centred ...:yes:
Chain tension? Best way I know of getting it spot on is to compress the rear end 'till the centre of the front sprkt,swingarm pivot point & centre of rear hub all line up, which is when the swingarm is at it longest point of its arc.
Hope this helps

chasio

21st May 2009, 21:59

Thanks, I'll try that on Saturday.

NordieBoy

21st May 2009, 22:42

Ever used a waterblaster to clean it?

awayatc

21st May 2009, 22:46

Had my chain wearing "uneven" but that took 7000km's.....

Waterblaster to powerfull indeed, and spray on goo picks up to much sandpaper grit (dirt)

Also throttle happyness doesn't help chain's lifespan much

puddytat

21st May 2009, 22:54

Weird, I posted an hour ago about this & it aint showed up, so at the risk of repeating myself.....
Is the rear sproket centered properly on its bolts....a thin bit of alu can round each bolt'll take up any slop
Best way I reckon to check for sure your not got your chain to tight is to line up the centres of the front sprkt, swingarm pivot, & rear hub by compressing the rear....Fat friends are helpful here. IT'll be when the swingarm is at its longest point & dont want to be tight.

Jantar

21st May 2009, 23:18

One possible cause of uneven wear is incorrect tension. If this was the cause then its too late to do anything about it other than put up with it. A small amount of uneven wear is acceptable, so check the limits given by the manufacturer. If the chain is out of limit then replace both chain and sprockets.

You don't say just how many thousand kms you have done, so maybe it has already served you well. A bike used on adventure rides will only get one quarter to a third the life of a chain used solely on the seal.

Skinny_Birdman

22nd May 2009, 08:20

You don't say just how many thousand kms you have done, so maybe it has already served you well. A bike used on adventure rides will only get one quarter to a third the life of a chain used solely on the seal.

Yeah, I'm a bit confused too..

....showing signs of uneven tension after only 500kms... ...my $200 chain goes south after only a few thousand kms on brand new sprockets.

500km or a few thousand? 500km sounds like dodgy alignment or poor tensioning as indicated by the others, or a dud chain. A few thousand km could be aggressive throttle action or use of spray-on goo, also as mentioned above. I find that Scottoiler lube works well on my adventure bike (which isn't fitted with a Scottoiler), as it isn't quite so tacky, and so doesn't turn to grinding paste after a few kms of gravel.

Cheers
A

The Pastor

22nd May 2009, 08:32

how much chain slack do you have?

Frodo

22nd May 2009, 08:37

The post is quite clear. After 500km he has uneven wear, and doesn't want it to be toast after a couple of thousand.

My last chain did 34,000km of mostly seal riding, lubricated with a Scottoiler. It still had plenty of wear left and the sproackets were okay. I got a dyno tune done and the tuner adjusted the chain to give about 20-25mm travel (okay for street bikes that he usually tuned, but my bike needs about 35mm). The chain was f*cked by the time I got home 500km later. This was clearly caused by incorrect tension. Should have checked myself, but with 34,500km I'm not complaining.

Story number two. A friend at work has an F650 and put new tyres on. The bike shop misaligned the wheel. This f*cked the chain and the sprockets. The bike shop relaced chain and sprockets.

I now have 3500km on a DID X-ring chain and haven't adjusted it since it put it on.

Hope this helps

clint640

22nd May 2009, 09:26

Check the axle alignment in the swingarm with a tape measure from the pivot too, don't rely on the marks on the adjusters until you know they are right.

Cheers
Clint

warewolf

22nd May 2009, 09:35

Slight tight spots would be normal, but nothing severe at such a low mileage. Definitely flag the issue with the supplier now, even if they say "see how it goes". You can still get dud parts these days; Nordie recently had a chain crap out prematurely.

Re: wheel alignment, are you familiar with the string method? Google it, that will give you a much better measure than by eye. Can be tricky with knobbly tyres but can be done.

Are your sprockets in line with each other, like the wheels? You could possibly string-line them like the wheels. Things can get out of line if the rear wheel spacers are fitted incorrectly - eg swapped sides off-setting the wheel - or either sprocket fitted reversed if they are not symmetrical. But that would have to be a long way out to cause issues, especially so soon. I ran the front sprocket on my DR-Z250 reversed to help protect the output shaft seal from mud, the sprockets were well out of line but chain life was still good.

The other comment I would make is that I only check the chain when it is hot. It always seems to have more/ worse binding links when cold, ditto when brand new. (I fit the new chain, set the slack, go for a 10 mins/ 10km ride, then check & set again. Kinda the same process you do when changing the engine oil.) Many of the tight spots found with a cold chain aren't apparent when it is at operating temperature. Not sure if this means it's only tight when cold, or they are obscured when hot.

chasio

23rd May 2009, 08:04

Hi all

Thanks for all your replies :) There's a heap of good stuff here that I will get into today.

The DID O ring chain has (now) only done about 600kms on brand new JT sprockets. I'm pretty easy on the throttle (I think), I've never waterblasted it and it hasn't been off road (even on metal) yet.

I've used kerosene and a rag to clean it a couple of times and a bit of WD40 as a light lube afterwards, then just left the Scottoiler to do its thing, tweaking the delivery rate up during heavy rain. When I have inspected the chain between cleaning, both sides of the chain have looked lubed OK to me, maybe the outside (scottoiler side) a bit better.

I'll have a ride and a tinker today and let you know how it goes.

Cheers again - Chasio

chasio

23rd May 2009, 08:07

Cheers for all the tips.

OK, with the assistance of 13 year old Chasiette, the string method showed up that the notches on the swingarm are out by about 1.5mm, meaning the right front edge of the tyre was cocked in a bit. That hadn't shown up by the lie down and squint method or countin threads, somehow. Lesson 1: don't be a lazy git. I've marked one face of each adjusting nut so I can keep them in sync.

Also using the tip of the ScottOiler as a reference, it appears to me that the rear sprocket has actually got a bit of lateral variation i.e. either it's not perfectly flat or the fitting is a bit out somehow... It's around 0.5mm variation I'd guess.

Now I just need to find a large friend to check tension and I'll check it again in another few hundred to see if it seems any worse.

cobber

24th May 2009, 09:46

YellowDog

24th May 2009, 10:15

Sounds like you are doing great in getting to the bottom of this. I sold my XF650 (not to a KBer) before solving very similar problems.

XF650

24th May 2009, 19:41

Chasio - have you checked your cush-drive rubbers?

puddytat

24th May 2009, 19:56

Cheers for all the tips.

OK, with the assistance of 13 year old Chasiette, the string method showed up that the notches on the swingarm are out by about 1.5mm, meaning the right front edge of the tyre was cocked in a bit. That hadn't shown up by the lie down and squint method or countin threads, somehow. Lesson 1: don't be a lazy git. I've marked one face of each adjusting nut so I can keep them in sync.

.

After seeing the damage a misaligned rear did to new tyres, I did the string thing & found that although the marks were exactly the same, over the length of the wheelbase my rear was 12mm out of line with the front...:gob:

rogson

24th May 2009, 20:34

There is a bearing in the sprocket carrier of the cush hub assembly. If it gets flogged-out it will lead to a wobbly/misaligned sprocket and result in increased chain and sprocket wear.

chasio

24th May 2009, 22:30

Chasio - have you checked your cush-drive rubbers?

There is a bearing in the sprocket carrier of the cush hub assembly. If it gets flogged-out it will lead to a wobbly/misaligned sprocket and result in increased chain and sprocket wear.

When I looked at the sprockets that came off, the front was a lot more worn than the rear and that sounds like it could match the above.

This sounds like a job for the PDF workshop manual and a long weekend at the speed and skill level I work at. I'll have a read and see if I'm feeling brave! :)

To align your sprockets borrow a gizzmo used by competive gokart racers , it is a clip on or magnetic laser attached to the rear sprocket and pointed onto the drive sprocket with the chain removed pretty fool proof and simple if you want to be very presice

This sounds clever. I'm not too close with any kart racers, but I know my boss's boss's boss's boss's boss is quite into it. Might be a stretch to ring him and ask to borrow his tool, though. :doh:

Sounds like I should check the cush drive area first.

Cheers to all for your input

Chasio

YellowDog

24th May 2009, 22:55

If anyone doesn't have the XF650 PDF Manual - PM me and I'll send you a download link.

warewolf

24th May 2009, 23:29

When I looked at the sprockets that came off, the front was a lot more worn than the rear and that sounds like it could match the above.No, that's normal. At roughly 3:1 gearing the front sprocket is doing 3x the work, they almost always wear out first despite being made tougher. My 640A goes through 2-3 fronts per rear and chain; leaving the front on too long flogs out the rear and chain, as the most-worn component brings the other 2 down to its level in short order.

chasio

25th May 2009, 07:08

That makes sense now I stop and think about it!

cobber

26th May 2009, 06:58

No, that's normal. At roughly 3:1 gearing the front sprocket is doing 3x the work, they almost always wear out first despite being made tougher. My 640A goes through 2-3 fronts per rear and chain; leaving the front on too long flogs out the rear and chain, as the most-worn component brings the other 2 down to its level in short order.

Totally agree with this as Ive done 78,200 kms on my dr650 since 2002 and getting near the end of the second chain and rear sprockets life though I change the front sprocket around 10,000kms using genuine Suzuki ones and a Scott oiler

chasio

31st May 2009, 20:18

Right, I took front sprocket cover off to have a look at it.

I noticed that there seemed to be a fair bit of play both around the axis as well as lateral "wobble". Reading up, a bit of lateral play seems to be OK but maybe not the axial play...?

I also noted that two of the three bolts were not tight. I read they need only 6Nm plus thread lock, but they were moving freely either way using a 10mm socket on a short handle with virtually no torque. I managed to get those two out with a bit of prying and the threads are full of alloy, so I am assuming that the bushes they're going into are stripped.

So my working assumption is that 1 tight bolt and two loose ones makes for a wobbly sprocket and increased chain wear. And I doubt it's especially safe, either.

What next? My thought is to refit with some thread lock and hope that makes it safe enough to ride until sorted out.

Anyone know what kind of mission sorting the stripped threads is likely to be? Maybe replace the stripped part or get a shop to fit helicoils... or is there another option worth looking at?

Cheers - Chasio