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525 chain on 520 sprockets

2K views 19 replies 7 participants last post by  crazypj 
#1 ·
anyone have any thoughts on what might be long term issues with this? i have a ducati monster 821 in for a service that had a new chain and sprockets fitted by the previous owner before selling it, allegedly done 12,000km this way. nothing looks overly worn or unusual.

i'm having trouble thinking what might go wrong, apart from it just feeling wrong. not something i've ever tried myself.

owner is happy to replace it, but i think i'm going to leave it and save him some cash.
 
#2 ·
Would have thought wear would be an issue, but as they've already covered that mileage I guess not.
I'd still change them though, you'd never forgive yourself if something went badly wrong.
 
#3 · (Edited)
The rollers on your chain are 1/16 th. of an inch wider then necessary and the chain is just slightly heavier as a result of more material.
If that is not creating any clearance problems whatsoever and the chain is tracking straight and true :/ should not be a problem other then it is just not 100% correct.

... which one is suppose to be on there 520 or 525?
I'm assuming the sprockets are correct and the chain is over-sized, the other way around would imply your sprockets have been down-graded and are not as robust as they should be.


add: there really should be no 'long term' issues with a chain that is 12,000 km old, chain is a consumable item and that one is likely due for replacement!

How stretched is the chain? <- best way I know to measure chain wear is to lay the old one along side a new chain and measure the difference in their length, roller chain should be replaced when it has elongated by only ~4% (& that is not very much)
 
#4 · (Edited)
I’m with Steveo on this one. Although it doesn’t show any wear now, I wonder about what will happen when it does. Will the extra clearance between the plates and sprocket allow the wear to accelerate faster than normal when things do start to go? Might not be an issue, but.... if you live in a land of litigation, then replace it. If it has a problem farther down the road, then there is a possibility of exposure for you.... at least there would be on this side of the pond.
It isn’t always a case of whether you are right or wrong... it’s a case of how much you can afford to defend yourself. There was a Kawasaki dealer of this side that we used as an example when explaining why technicians should look for safety issues and note them on the repair order.... which the customer would eventually sign. Long story short, a customer’s chain broke, locked up, and the rider was seriously injured. The dealer argued that the chain had nothing to do with the service provided, but at the end of the day he lost his dealership.
 
#7 · (Edited)
Cyorg and Steveo raise good points.

If someone gets hurt or killed, and the cause can be traced in any fashion to the chain/sprocket mismatch, sadly, your admirable desire to save your customer money probably won't go far in defending the lawsuit against you and/or your shop.
You may want to consider calling the technical support line of one of the big drive chain manufacturers or distributors and pose this question to them. Although, for liability reasons, I would be surprised if they told you that this combination was safe to run, as experts on drive chains, they should be able to tell you any reasons why it would not be.

If you decide to do this, please share what you learn. Good luck.
 
#8 ·
You figure it could fly off and kill somebody just because the chain rollers are .0625" wider then the sprocket teeth?

:| not seeing how it could possibly do that unless his wheel is badly out of align, or the swingarm bushings are completely worn out, or there are no teeth left on his sprockets.
any of which would make an excellent defence for the accused.


No drive chain manufacturer is going to suggest it's an acceptable practice, why would they!
 
#9 ·
any of which would make an excellent defence for the accused


Is your geocentric thinking is getting in the way? ... courts are different where you are. We don’t... or at least I don’t know what things are like down under. The Kawasaki dealer I mentioned never touched the chain, but still ended up losing his dealership. Again it doesn’t always boil down to right and wrong.... it boils down to how much you can afford to defend yourself, how long you want to fight it out, and how much “press” you want for your business. Have a look around at some of the motorcycle related cases. Lots of cases just get settled because the it’s cheaper for the defendant. Or if it goes to court, sometimes the manufacturer or dealer gets fucked over just because they can afford it. In a lot of them fairness has nothing to do with it... unfortunately. My job got me some seat time (for the defence) on the witness stand in your fair province. It involved a case that should never have got to court. Even in the end... although fairness prevailed the cost to defend the case as much or more than the claim..... and that was using my cheap labor instead of the company lawyer.

Ps. One could debate the fact that the Kawasaki dealer should have checked the bike over and told the customer the chain was on its last legs, but that’s a different rabbit hole.
 
#10 ·
Is a moot point because that chain is going to have to fly off and kill somebody in the first place,
and the original seller in this case brought the issue to the buyers attention (full disclosure)
buyer passed on having it addressed at no additional cost :| Judge Judy would laugh hysterically.
 
#11 ·
Trials,

No drive chain manufacturer is going to suggest it's an acceptable practice, why would they![/QUOTE]

I agree with you 100%. This is why I said "for liability reasons, I would be surprised if they told you that this combination was safe to run...." The manufacturer or distributor is not going to expose themselves, gratuitously, to a potential liability claim. However, I added that "as experts on drive chains, they should be able to tell you any reason why it would not be."

Aside from saying "we don't recommend it," if there are specific reasons that this combination is not safe, perhaps the technical representative would share some reasons that none of us have thought of, as to why it is not.

As regards the other possible mechanical problems which could cause the bike to toss the recently-installed, mismatched chain, you can be sure that if someone were to get hurt or killed, among the very first questions asked will be who last serviced the bike and what they observed to be its overall condition, including the component parts you listed, and whether their condition was brought to the owner's attention in a documented fashion (e.g., on the repair invoice). Not that installing a mismatched chain on sprockets without teeth could likely be excused, in any event.
 
#12 · (Edited)
"among the very first questions asked will be who last serviced the bike"
Up here the first question would be; when did driver last consume alcohol.

Even a safety certification is only good for 30 days (required before you can get a plate up here) if bad happened in that period yes, questions will be asked, otherwise highly unlikely unless said chain flew off and went through some innocent bystanders head. If the mechanic was decent and noticed the issue they would not let it pass.
In Ontario, I'm thinking, on average he would be forced into buying a new chain if only because most of the mechanics that do motorcycle certs work for a place that sells chains.
 
#13 ·
the owner was happy to stick with it, given it had lasted so long without issue thus far. i don't see that it will suddenly go bad just because he now knows about it.

no one is going to recommend it - i wouldn't insult their and my intelligence by asking.
 
#15 ·
I don't even like sealed chain anyway, I would just replace it, put a link master on it and service it regularly
but that's just me.
Should be about eighty bucks I think was my last one and it was 20 links too long,

theoretically if i just keep buying them like that I could have an almost free chain with every 5 purchases
lol except for the cost of all those master links
 
#20 ·
JHFC, chain manufacturers went to a 'code' ? ? years ago and no one knows what it is? Chains are still measured in Imperials sizes, 1/8" or 0.125" increments 520 means 5/8" x 2/8" inch (1/4") thirs digit is the 'divider' (0.5 x 0.125) or 1/16". It's acceptable to have extra clearance, in fact, enduro riders have been doing it for years (usually narrowed sprocket) TrialsRider has the info a few posts earlier. I would imagine he's used the clearanced sprockets when deep mud is involved in a trial? I used both wider chain and modified sprockets when I was doing Enduro's, Sometimes mud would still build up and cause chain breakage. ( Long ago, around 1980, brand new chain and sprocket set on modified XL185, chain snapped after only 35 miles) For a street bike, it's just a little bit wider and heavier, 525 was probably cheaper than the recommended 520?
 
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