snapped chain
 

hi guys
I'm currently in Amman Jordan on a round the world trip and my chain has snapped. hopefully i can get a new one here and keep going. The thing is that I replaced the chain and sprocket 1000km ago am I am wondering why its snapped. for the past few days I've had to tighten it every 200km. I think it's a bad chain and it's been stretching, has anyone heard of a problem like this before. I'm on a 06, 650GS, the front sprocket is fine and I am baffled. I don't want to put a new chain on it only to have the same problem again.
thanks for your help guys
Kev

Chain
 

Hi mate, ive not heard of a chain breaking as such. I would worry at the agustment u are doing, how much slack u have in the chain. With a load on and your weight u need it rather slack as the suspention moves a lot in its travel. Id say 50mm or more at a stand still, with u off the bike, well thats what i do on my Suzuki. All the best and make sure u carry a spare chain and spare sprokets when u get the chance. All the best Brian B:thumbup1:

B grade Chain
 

When we hit Namibia (my original chain lasted from Morocco and over 30,000km's) we opting for a much cheaper chain and within less than 2000km's the chain had to be tightened daily! When I was riding one day, I heard a sudden crunch and when I looked down, the chain was completely off the sproket!!!!

The chain however never snapped off but we got so fed up with it, we got a new one put on Namibia!

Good luck finding a new one

Amy

P.S where are you Brian Bayley??

Chains don't "stretch", strictly speaking. What happens is that the link pins wear and the chain gets longer as a result. Also, each of the bearing surfaces that make contact with the sprockets suffers wear which makes the chain sloppy on the sprockets. Both sorts of wear result from lack of lubrication and cleaning. The link pins need lubrication even on an O-ring chain in order to keep the O-rings moist, sealed and doing their job. If they dry out or get damaged water and grit soon get in and they seize and/or wear very quickly. See the separate postings on chain oilers. With a chain oiler or regular lubing (with engine oil or, better still, the more viscous gear oil or chainsaw oil) chains quite commonly last 20k miles and more with little interim adjustment needed.

It may be worth sitting on your fully loaded bike with some one ( or thing ) blancing you, then check the free play, chains usually only break when over tightened, it wont do the gearbox output shaft bearings any good either. As has been said, maybe a poor quality chain.
I would expect a chain in the sixties to last for 8-12 thousand miles. Presumably the new ones with the x or o rings are better.

Rear wheel alignment
 

In addition to what has been said, check the rear wheel alignment to make sure your chain is running straight. I know you probably set the graduation marks equal on each side but on some bikes they are not equal and you need to look along the chain to make sure it's aligned with the front and rear sprocket.
Best to buy a good chain and pay more and by it as a set with front and rear sprockets.
Cheers
Ian :thumbup1:

Thanks again guys
 

Hi guys, thanks for the advise
I managed to get a new chain with o rings, actually I had to buy 2 chains and join them up as they were 2 short, buy hey problem solved.
the chain I had on was a cheap Chinese model, it was sold to me by a Turkish shop at an outrageous price and he guaranteed it was good,
well I can keep going anyhow
Thanks again
Kev

That is a sign - pay attention when you need to do things frequently .. something is about to go.

Any chain will ware .. once worn to a certain extent it should be replaced ..

On my DR650 if the rear wheel is adjusted 2 full marks backwards from having a new chain then it is at the limit of that chains ware .. there are many more marks available .. but the chain itself has reached its life according to the manufactures ware limit. After that you are on borrowed time .. and because the chain is worn it will are the sprockets faster too..


KevOK .. I'd be looking for a new front sprocket ... just in case.

Frank,
Different subject, but I've found that a 14t sprocket gets too well-worn before the chain is gone on my bike. A 15t has been different, going with the life of the chain.
Although conditions are always different and it's not been correctly measured tests, I believe that the 14t cuts the chain life to some important degree.
I really like the 14t/43t gearing for my needs.

I can't think why you would notice a measured difference between a 14 and 15 sprocket. But if you want to keep the gearing the same you could use a 15 front with a 46 rear and have almost the same ratio.
14 / 43 is 3.071 to 1 and 15 / 46 is 3.067 to 1. It does mean you need a longer chain but worth concidering next time you change the sprockets. Check to see you have extra clearence for the chain on the larger sprockets with the swing arm movement.

Steve

Chain drive systems ... best effeciency wise if the sprocket sizes arte 16 tooth and up ..

The DR is poor that way ..
As the sprokets get smaller you increase ware on both sproket and chain ..

---------------------
On large rear sprokets .. chain speed in increaes as you'd expect.
And cheking the cahin clearence is an issue with the suspension fully compresssed on the top chain roller .. think that is why some have had it break.


Edit
Opps ... Susi DR .. not teh F650 .. don't know the detail there... the 16 tooth info remains the same.

Rapid chain wear on an F650
 

Kev

I've had a similar experience, although I think the chain lasted 3000 miles. It was a standard BMW chain, lubed through a Scottoiler. Thinking back, it happened shortly after I did a trip heavily loaded with luggage and my wife (we're both a bit too large for an F650). Maybe that contributed. The chain seemed to stretch over just part of its length, with tight and slack sections. After that it couldn't be correctly adjusted.

The F650 seems to go through chains at an alarming rate. The best I got was 10,000 miles from a Renthal X-ring. I've heard that the DID O-ring is the best.

Robert

DID X ring
 

DID it is for me too.Never had one break ever,but then i do pamper them a bit and am very particular about tension and lube.A couple of points worth noting if you're going RTW with a DID chain is to take a couple of spare DID split links with you and that spare few links you cut off when you fitted the chain in the first place....DID links are slightly different size to all other makes and nothing else will fit! Another tip (enduro riders use this) if you're riding in rocky/shaley terrain is to run your chain a tiny bit slacker than normal as it reduces the chance of breakage by small stones getting between sprocket and chain.Sprocket tooth wear will be accelerated though so re-adjust when you get off the rough bits.

Chain
 

Best IMHO is the DID 520 VZ X-ring
Next one down and the the one is the DID Gold 520VM -Xring
+ original BMW front and rear sprokets.

Best practice is to change all 3 at the same time if you can.
Chain tension is very important -and lube properly
Should last a loooong time.
A few spare links are good to and I always have the chain sealed properly when new- It does mean dropping the swing arm to replace.
And as has been said before - you should really be carrying a spare. especially on a RTW!
DID Gold 520 VM Xring features: Tensile Strength 8120 lbs. Max bike engine size cc 750
specific: wear resistance 3450, standard = 100
BTW I ride a F650GS Dakar- perfect for it in sand, mud and under water in Africa!