My chain broke without warning

[the big mike]

Just for information: most of my riding consists of doing 100 km of highway, twice a week.
I've had my chain and sprockets replaced almost 2 years ago and in the mean time they lasted for 17000 km

When my previous chain wore down, it would let that know by stretching very fast, making me have to tension it every 2 weeks.

With this chain, I rode 17000 km, I never noticed my chain becoming loose or anything, but yesterday it broke on me.

I was doing my weekly trip of 100 km of highway when I finally entered the city for my final km, splitting between cars who were waiting for a green light. Suddenly I heard some cracking and my ninja stopped. Apparently the chain did some weird things and is now stuck near the front sprocket. There was no way I could make it move and so I couldn't push my bike out of the way.
Man there were some angry drivers

I called a towing service to bring me to my destination, that cost me €240
now I have to find somebody who can pick up my bike without having to pay for it
Question is, why would my chain do such weird things just like that? I was riding really calm on that moment...

[Alex]

What did the chain look like that morning? What type of chain lube do you use, and how often are you able to apply it? 17k miles is a little early for a name-brand chain to wear out on our bikes, do you remember which type you replaced the OEM one with?

[old3]

Sounds like you are possibly running it too tight.

Edit, you rode it 17,000 miles? Never mind the previous. You got a full life from it and anything can happen at that point. What do the sprocket teeth look like? Have a pic?

[csmith12]

I am happy for you it didn't break a pace, could have been a different thread altogether.

[lgk]

pics?

[JohnnyBravo]

Hate that your chain broke, glad it didn't turn into a different thread

[broilmebk]

Oops. Read OP wrong. He did say this chain is 17k miles. Not sure why he changed up units.
17k is a lot of miles, especially without proper maintenance. What does the chain look like?
:

[rasta]

Man those drivers must've been pisssssssed. Good thing it didn't happen when you were doing 80 on the highway

[greenaero]

17,000 km is only 10.540 miles; not very good for chain life. I had a chain failure on my '99 Ninjette but the chain was in bad shape when I got it in Dec.2011 with 23.6 K miles on it. I rejuvenated it a bit and put another 7-8K miles on it before it failed. Fortunately I was only a few miles from home so it was fairly easy to get it back home.
Shaft drive motos spoil you, good chain maintenance is important for good chain life and safety.

[Alex]

The OP used both miles and kilometers in his post, so it's somewhat unclear the full life of the second chain. Either way, even 17k miles is on the low end (unless it was a low-rent chain).

[alex.s]

"never noticed it becoming loose" sounds like "it never sounded horrible so i never bothered to look at it"

[broilmebk]

Originally Posted by Alex

The OP used both miles and kilometers in his post, so it's somewhat unclear the full life of the second chain. Either way, even 17k miles is on the low end (unless it was a low-rent chain).

Ugh really? I knew I wasn't taking care of my chain well enough needing to get a new one prematurely, but I didn't know it was THAT bad.

[the big mike]

Originally Posted by Alex

The OP used both miles and kilometers in his post, so it's somewhat unclear the full life of the second chain. Either way, even 17k miles is on the low end (unless it was a low-rent chain).

yes I'm sorry, I mean 17,000 km (10.540 miles). I made that mistake because all of you guys always speak in miles ('mericans ) and it became some kind of a reflex when visiting this forum

[the big mike]

Originally Posted by alex.s

"never noticed it becoming loose" sounds like "it never sounded horrible so i never bothered to look at it"

I see what you mean, but it's not that. As a matter of fact: in the beginning I looked after my chain TOO MUCH

Click here for evidence

[the big mike]

Originally Posted by greenaero

17,000 km is only 10.540 miles; not very good for chain life. I had a chain failure on my '99 Ninjette but the chain was in bad shape when I got it in Dec.2011 with 23.6 K miles on it. I rejuvenated it a bit and put another 7-8K miles on it before it failed. Fortunately I was only a few miles from home so it was fairly easy to get it back home.
Shaft drive motos spoil you, good chain maintenance is important for good chain life and safety.

Really?? my OEM chain only lasted 12000 km. that is even 5000km less than this one. I thought I was doing well

[broilmebk]

What do the chain and sprockets look like?? That's even worse than mine.. Is the rear wheel aligned properly? Tension?

[the big mike]

Originally Posted by Alex

What did the chain look like that morning? What type of chain lube do you use, and how often are you able to apply it? 17k miles is a little early for a name-brand chain to wear out on our bikes, do you remember which type you replaced the OEM one with?

I use MOTUL chain lube, the white racing variant (factory line). I apply it to the chain every 3 or two weeks.
I must admit that I didn't check my chain before leaving.
And I know it was an O-ring chain, but I don't have anymore details than that.

[the big mike]

@old3 @lgk @broilmebk
I'll take some pics tomorrow, it's dark outside now

[Alex]

Originally Posted by the big mike

I use MOTUL chain lube, the white racing variant (factory line). I apply it to the chain every 3 or two weeks.
I must admit that I didn't check my chain before leaving.
And I know it was an O-ring chain, but I don't have anymore details than that.

Good info - if it was lubed and adjusted properly, and you still only got 10k out of it, the remaining data point is the quality of the chain itself. Plenty of horror stories about cheapo chains failing early (search "volar" for examples on this site), but it's much rarer for a DID, RK, or other name brand chain to have unexplained issues.

[Whiskey]

You did chain & sprockets 2 years ago, did you use steel or aluminium sprockets?

Do the teeth look hooked on the front sprocket? It's about 1/3 size of the rear so wears 3x faster & is hidden from casual view so unless you check it you may miss it.

That'll ruin a chain in very short order.

[Xtina]

Originally Posted by the big mike

I use MOTUL chain lube, the white racing variant (factory line). I apply it to the chain every 3 or two weeks.
I must admit that I didn't check my chain before leaving.
And I know it was an O-ring chain, but I don't have anymore details than that.

I hate the Motul chain lube. it attracts so much crap since its so sticky.

[old3]

Dry sealed chains are happy chains in my garage. I do 3-4 drive sets every year on a MX bike so the street stuff going over a year is a treat IMO. I never lube them. Swap the front sprocket once or twice and toss it all when it is shagged.

Even my street chains see enough dirt that lube just attracts more gunk and wear.

[the big mike]

I'm having some issues

I unscrewed the 3 bolts that hold the cover of the front sprocket, as wel as the bolt that holds the gear shifter, but I still can't remove that cover.
So to answer your questions: I still didn't have the chance to get a good look at it, because it is all stuck.

I have managed to arrange a trailer to get it home, but it won't be sooner than friday. Over there I have more material and maybe I can get it loose, but until that moment my bike is standing outside in the cold rain.

@Alex , I'm getting scared actually... As it is now, the chain has lost its tension and is clearly hanging, I'm afraid that it might not be the chain, but my transmission or something else... that would be BAAAAAAD

[the big mike]

Originally Posted by Xtina

I hate the Motul chain lube. it attracts so much crap since its so sticky.

I like that it's sticky, otherwise it flings and messes up my rear rim and the rear plastics...

[old3]

The chain is still on the bike? I'm going to bet you have rounded the countershaft sprocket off!

[Alex]

Make sure you have all of the cover bolts loose, I am not sure if there are 3 or 4. If there are only 3 and they are all removed, then just apply some more force to the cover and it should pry off.

Your fear about other things being broken is unfortunately valid. When the chain broke and wrapped around the countershaft sprocket, locking it up instantly, it provided a ton of force to the transmission output shaft. It's certainly possible something broke internally, though not guaranteed.

[Xtina]

Originally Posted by the big mike

I like that it's sticky, otherwise it flings and messes up my rear rim and the rear plastics...

Yes but it also attracts all the crap that destroys chains prematurely too.
With the non-sticky lube just wipe the extra off with a shop towel. I don't have an army of lube on my tail or plastics.

[the big mike]

Originally Posted by old3

The chain is still on the bike? I'm going to bet you have rounded the countershaft sprocket off!

Originally Posted by Alex

Your fear about other things being broken is unfortunately valid. When the chain broke and wrapped around the countershaft sprocket, locking it up instantly, it provided a ton of force to the transmission output shaft. It's certainly possible something broke internally, though not guaranteed.

in that case, what conclusion should be made? Can I already assume that it will be the case that there is more damage? and if so, is it expensive, very expensive or just useless to have it repaired/replaced?
- in the case of just the countershaft sprocket
- in the case of a bended shaft

and also, could such damage be caused by something else but the chain?

It would be a shame I put so much work into this bike...

[old3]

I had to reread your first post to see the symptoms again. It is probably bunched up in there, the only way to survey the damage is to look. You may have scratched the paint on the cases or destroyed them. Can't tell till you take it apart enough to see it.

Is the end of the chain hanging off anywhere or is it all still continuous?

[Alex]

I think you need to take it step by step. If the sprocket itself is toast as old3 suggests, replacing just the sprocket is dirt cheap. Probably makes sense to replace the rear at the same time, so your new chain is starting with new sprockets on both ends.

If you get the chain off, replace the sprocket, but are not able to shift properly or are hearing some unusual noises from the transmission, the troubleshooting continues. @alex.s might have some ideas to identify transmission issues, along with when to cut bait and just replace rather than repair.

[alex.s]

there are 4 bolts on the sprocket cover. also you need to completely remove the bolt from the shift linkage before the knuckle comes off (which obviously has to happen before the cover can come off)

once you get the cover off, bend the sprocket lock washer down and use an impact wrench to remove the sprocket bolt (do not unjam the chain before doing this. the chain will hold the sprocket in place which you want in case there is any damage internally)

once the sprocket is unscrewed, slip it off along with the chain. wiggle the output shaft. if it wiggles at all then you have screwed up the output shaft bearings (they cost about $5) wiggling in and out a few mm is ok. if it seems okay, try putting the shift linkage back on, and try shifting while you turn the output shaft with your hand. can you get it into and out of neutral? then put the new chain and sprocket on, put everything back, and see how it rides.

[broilmebk]

Just so you don't go crazy trying to find the 4th, there are actually 3...

[tfkrocks]

The sprocket cover usually takes a bit of wiggling to get off, especially if it hasn't been removed in a long time.

[alex.s]

Originally Posted by broilmebk

Just so you don't go crazy trying to find the 4th, there are actually 3...

the 4th bolt is on the linkage

[old3]

I'd unjam that chain if it is wedged in there. No need to put the force of a impact gun into the cases via the stuffed chain. Would you jam stuff in there to wedge the sprocket/chain against the case to ever do that job?

If stuff is muffed inside, it is muffed. Period. Breaking the engine case with an impact gun just brings more bad.

[the big mike]

Originally Posted by alex.s

there are 4 bolts on the sprocket cover. also you need to completely remove the bolt from the shift linkage before the knuckle comes off (which obviously has to happen before the cover can come off)

once you get the cover off, bend the sprocket lock washer down and use an impact wrench to remove the sprocket bolt (do not unjam the chain before doing this. the chain will hold the sprocket in place which you want in case there is any damage internally)

once the sprocket is unscrewed, slip it off along with the chain. wiggle the output shaft. if it wiggles at all then you have screwed up the output shaft bearings (they cost about $5) wiggling in and out a few mm is ok. if it seems okay, try putting the shift linkage back on, and try shifting while you turn the output shaft with your hand. can you get it into and out of neutral? then put the new chain and sprocket on, put everything back, and see how it rides.

solid advice only problem: I don't have an impact wrench...

Anyhow, how about this: would it be a good indication if I just removed the chain and tried to wiggle the output shaft with the sprocket still on it?
Depending on the results you described, I would have it repaired by some pros (or not if it's really broken and the cost wouldn't be acceptable...)

[JohnnyBravo]

Hope your bike comes back with minimal damage this is an awful story indeed.

[alex.s]

Originally Posted by the big mike

solid advice only problem: I don't have an impact wrench...

Anyhow, how about this: would it be a good indication if I just removed the chain and tried to wiggle the output shaft with the sprocket still on it?
Depending on the results you described, I would have it repaired by some pros (or not if it's really broken and the cost wouldn't be acceptable...)

yeah if you can get the chain off. i was under the impression it was stuck. the sprocket will wiggle a bit more than the shaft itself

[old3]

Mike, un jam it, inspect the chain/sproxs for damage, replace the entire drive set and ride it. This type of event happens pretty regularly to unskilled wrenchs on dirt bikes. If the case has a hole in it, it is another story.

Unless you want to tear the engine down to split the cases, you won't know if there is internal damage until you ride it. I doubt there would be. These assemblies take huge stress loads and shocks constantly.

Post up pics as you uncover it and get it apart. If you listen to nothing else, don't hit that nut with an impact or breaker bar on a socket until you remove any chance of the chain breaking the engine case.

[the big mike]

Ok, it's friday so i got to it I'm very lucky: it's only the chain

One of the links was broken and jammed the whole system. IT EVEN BROKE THE COVER!!!! (well, it might as well be me 'cause I used a lot of force to remove it )

I tried to wiggle it as @alex.s described and it didn't move. It just turns without problem

I also took some pictures of the sprockets. Do you think it's necessaire to replace the sprockets and chain together, or do I just put a new chain on it?

EDIT: also, I'm planning to reuse the cover as it is. would that be a problem?