Right, so I just picked my xr600e up from the garage, having just been MOT'dand new front and back disc and pads. 3miles down the road, the chain comes off,fortunately stopped safely. So my question is, is it likely something the garage did that may have caused this? I didn't check the bike over when I picked it up, may be naive to think everything would be fine.
Do you think the onus should be on the garage to fix the problem?

Hi !
To replace the rear brake disc they would have removed the rear wheel. So my guess is they didnt tension the chain correctly when they put it all back together or if it was a chain with a split link they didnt refit it correctly. That would be my guess. Was the chain broken at the split link? Of course it could be coincidence if the chain had snapped

Bill

Just thinking, if the brakes needed sorting for the mot. Then they should have done them first and then undertook the mot. I dont know for sure but i would suggest the chain condition including its tension would have been checked and obviously passed to get the certificate.

Bill

Just checked mot website and it says "the chain/belt must not have excessive slack and be in good condition, the guard must be secure and not fouling" i know that an mot is not a guarantee of condition of a vehicle once its left the testing station. But i would say that such a catastrophic failure of such an important part shouldnt have been overlooked.

Bill

This is a pretty serious fault by the MOT shop. You could have died if that chain had come off at high speed. Serious.
No question they did it, they were just working in the area. No doubt on this one.

They should:
1. come pick you and the bike up, give you a loaner bike while they repair the bike. ALL FREE to you.
2. It's very possible the chain will have been DAMAGED when it came off or could have done damage to the bike (engine case, swing arm ext.) Any damage done is on the shop. Look closely for damage, a chain can break the engine case in rare cases, can dig deep into swing arm, but mostly it's the chain itself that gets damaged. Any question on the chain, demand a NEW chain.

3. I'm guessing they simply forgot to tighten up the axle bolt. Once riding, the torque pulled the axle forward, chain got very loose and came off. A common error by shops and home mechanics alike.

4. If the chain is in ANY WAY damaged ... I would demand a NEW chain.

If they give any trouble I would go to whatever agency monitor these MOT Shops and report the incident. They are on the hook for ALL damage.

Always a good idea to check over your bike after a shop visit ... but must admit, a loose axle nut is not something I would have caught. A real bummer and consider yourself quite lucky on this one! I would also ask for my MOT fee back.

Need more info, otherwise were just guessing. I'd speak with the mechanic for sure.

Did the chain just derail and is fine, or did it break, or is is split at the connectorlink (rivet, clip-type ect)?

1) Could lead one to believe the chain wasnt tightened properly
2) Seems like bad luck
3) Could be both, but its unlikely the shop should have disconnected the chain, theres no need to.

I would say with out looking at your bike that ether one side or both sides of the wheel alinement bolts was probably not adjusted or left loose and forgot to do,,,,,that's so common, very lucky indeed I would be on the phone to verbal them to see what they are going to do to help you sort this out,

Hi mollydog
My first thoughts were that they hadnt tensioned the chain properly. But they should have picked this up when they carried out the mot. My chain has a link but even so i dont touch that for simply removing the wheel. I was thinking other than a catastrophic chain failure (very coincidental ) and again any chain that looked in poor condition would surely have failed or at least flagged up an advisory during the test.if the op confirms the chain is in one piece still, then as you said it must have jumped the sprockets.

Bill

Jens, we don't have to guess on this one ... it's clear to me what happened.

I don't believe chain was left loose ... but the Axle Nut was left loose, so when you ride ... axle moves forward, chain gets very loose ... and comes off! I've done this a couple times!

Bad Luck? Not at all ... this is INCOMPETENCE, pure and simple.

You're correct, the shop would NOT have disconnected the chain. No need to remove chain to install new pads or a new rotor.

Simply loosen axle nut, use Snail adjusters to move axle forward creating enough chain slack, then simply lift chain UP and OFF rear sprocket, set chain to one side and pull wheel out. It's that simple.

I've done this .... A THOUSAND TIMES. The chain master link is never touched to change pads.

To be clear on this. I dont think the shop would have split the chain to remove the wheel/brake disc.

I think the most likely answer is the chain was tensioned afterwards but the rear wheel spindle wasnt tightened. This is obviously down to the shop.
BUT

All im suggesting is that tgwmako checks the chain (if possible) and sees if
its broken at the split link or elsewhere along the its length. Just so hes ready for any possible excuses from the shop.

The shop might hold their hands up right away of course and pay for all damage without fuss. I hope so anyway

Bill

Thanks, all these replies have really helped understand what went wrong. The garage have been suitably regretful and have picked up the bike. They're going to replace the chain and sprockets. I may just take it elsewhere afterwards to get it checked over!!

Thanks again, really helpful

Tom

Hi Tom!

Glad the shop are picking up the bill. It could have so much worse for both of you! Is there definately no other damage though?

Free mot's for years methinks!

Bill