How much chain stretch is OK?

[Black Bandit]

I've had my bike for about 5 1/2 mths now and am concerned by the amount of stretch in the chain. The chain was new when I bought the bike from the dealer and it's a decent (as far as I know) Japanese "DID" brand chain - non o-ring.

I've done about 6000 km in that time and finding that the chain requires retensioning every 200 - 300 km. I mean reeaaalllly needs retensioning - it's so loose it clatters about the frame over bumps. Have been re-oiling the chain at similar intervals. Trouble is I'm almost out of travel on the swing arm.

Is this amount of stretch normal? Is the chain shagged and do I need to buy a new one ASAP before it throws me and the bike down the road?

If this is not normal, what could cause such unprecedented stretching?

[SwanTiger]

When was the last time you replaced your front and rear sprockets?

Generally it is recommended that you replace both the front and rear sprockets when you replace the chain. If you don't, then the wear on the chain is increased and obviously the lifespan is shortened. Replacing the chain and sprockets at the same time also makes the bike feel a lot smoother, well, usually.

[FilthyLuka]

hmmm, how i do it. i adjust the chain untill there is two fingers worth of up/down movement in the middle of the chain. works good. Make sure you have your chain adjusted properly or something bad might happen! i know a dude whose chain fell off on his quad and proceeded to tear through his bike and his engine... :O

also, if your adjusters have run out, REPLACE YOUR CHAIN! if you value your leg that is...

[Black Bandit]

hmmm, how i do it. i adjust the chain untill there is two fingers worth of up/down movement in the middle of the chain. works good. Make sure you have your chain adjusted properly or something bad might happen! i know a dude whose chain fell off on his quad and proceeded to tear through his bike and his engine... :O

also, if your adjusters have run out, REPLACE YOUR CHAIN! if you value your leg that is...

yeah, it's not the adjustment that's the problem, it's the frequency - almost every 12 days. If I do need to replace the chain ... and the sprockets - it becomes an expensive exercise. Tyres are starting to look a little shady too

[FilthyLuka]

errr, solid bush chain = $80, rear sprocket = $40 front, front sprocket = $30-40. Atleast its like that for the ginny...

[T.W.R]

If you can pull the chain away from the rear of the back sprocket more than 5mm it's Fucked !

[Ixion]

Hm. A good quality chain on a smallish bike, even a non O-ring job shouldn't need adjusting more than once every 3 or 4 thousand km.

You say that you adjust to a couple of fingers movement . That's about right AT THE TIGHTEST POINT OF THE SWING ARM MOVEMENT. Important, that. You're not adjusting it with the bike on the centre stand, by any chance? If you are, you're almost certainly overtightening it.

Otherise, maybe the chain isn't actually what you think? Like all good things, there are counterfeits out there.

Check the "fit" around the rear sprocket. Try to pull the chain off the back of the rear sprocket. Any more than a few millimetres and the chain is worn (they don't actually stretch, it's wear).

A fast wearing chain may not need new sprokets. Normally the conventional wisedom is true. but a cheap chain can wear out long before good quality sprockets.

[SwanTiger]

It should be around $60 for the front and around $100 for the rear (sprocket) wise. You can get a cheap chain for around $70 or an O-ring chain for around $110 if I recall correctly. So a minimum of $230 in total isn't really that bad when you look at the big picture. Let's assume you get at least 10,000 km's out of the new sprocket and chain, that's around .02 cents a kilometer.

[erik]

What type of chain lube do you use? I'm wary of the white waxy types of chain lube, I don't trust them to lubricated the chain. It's gotta be oily and make a mess of the back wheel in my opinion.
You're putting the chain lube on by having the bike on the centrestand (I think the bandit 250's got one eh?) and rotating the rear wheel backwards, by hand and spraying the lube on the upper surface of the lower chain run - by lubricating the inner side of the chain the oil should work its way to the outer surface as the chain goes round the sprockets.

[erik]

It should be around $60 for the front and around $100 for the rear (sprocket) wise.

I'm pretty sure the JT sprockets for my Zeal were cheaper than that, closer to $10 for the front and $50 for the rear, roughly.

http://www.jtsprockets.com/ (search their catalogue to see what the available sizes for your bike - that is if you decide you want new sprockets.

I know Mt Eden Motorcycles gets JT sprockets, probably a fair few of the other shops do too.

[Black Bandit]

What type of chain lube do you use? I'm wary of the white waxy types of chain lube, I don't trust them to lubricated the chain. It's gotta be oily and make a mess of the back wheel in my opinion.
You're putting the chain lube on by having the bike on the centrestand (I think the bandit 250's got one eh?) and rotating the rear wheel backwards, by hand and spraying the lube on the upper surface of the lower chain run - by lubricating the inner side of the chain the oil should work its way to the outer surface as the chain goes round the sprockets.

I have to admit I wasn't using the best quality lubricant money can buy - just some spray-on stuff from Repco designed for "general chain lubrication".
The lil bandit only has a side-stand so I use a trolley jack to make adjustments and respray. Looking at the sprockets I'd say that they could stay on, they're in good condition.

[Black Bandit]

Would an o-ring chain be a good choice or will this add needless mass to the transmission and result in reduced performance?

[jonbuoy]

Are you sure its not being pulled back to the original position after a ride? Could be chain is too tight when your sat on the bike and is pulling the wheel forwards (if you haven't tightened the rear wheel nut enough this will also happen - use a torque wrench). I mark the adjuster to swingarm with a marker pen so I can see how much I have tightened it by.

[Lou Girardin]

The standard chain is either a O ring or X ring. Unless it's a race chain, the non- O ring will be a cheap and nasty.

[Black Bandit]

Are you sure its not being pulled back to the original position after a ride? Could be chain is too tight when your sat on the bike and is pulling the wheel forwards (if you haven't tightened the rear wheel nut enough this will also happen - use a torque wrench). I mark the adjuster to swingarm with a marker pen so I can see how much I have tightened it by.

Nah, the swingarm has engraved markings on it - definately not moving.

The standard chain is either a O ring or X ring. Unless it's a race chain, the non- O ring will be a cheap and nasty.

Hmm maybe it was fitted with a dunger, so any suggestions for the next chain?

This link has some interesting tips - first thing I noticed is that I was not lubricating the chain as demonstrated in the diagram at the bottom of the page.
http://www.quality-cycle.com/truth_a...cle_chains.htm