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Chain Ajustments

Discussion in 'Bling and Appearance' at netrider.net.au started by rthrelfall, Sep 12, 2006.

  1. how do i go about ajusting my bike chain on a zzr250

  2. Step 1: Remove split pin from rear axle and loosen axle nut.

    Step 2
    : At each end of the swingarm you should see a bolt sticking out with two nuts on it. Loosen the back nut on each bolt (this is a locking nut).

    Step 3
    : Tighten the front to nuts equally to increase the tension on the chain, or loosen them to decrease the tension.

    Make sure you keep the back axle perpendicular relative to the swingarms, if it is out of alignment it's not a good thing. There are small marks in the top of the swingarm to help you keep things lined up, how much you trust them is up to you. There are guides on the net (google for them) on how to align the rear axle if you want to be certain about it.

    Step 4: Measure chain slack, ie the distance between the top position you can stretch the chain to and the bottom position when you push it down. I find it easiest to use a small ruler, and to measure from the bottom of hte swingarm. The manual says 35-40mm slack.

    Step 5: When you've got it tensioned correctly, tighten the locking nuts back up, tighten the axle nut, and don't forget to put the split pin back in.

    Step 6: While you're at it, give the chain a good clean and lube. Always double check at the end that everything is done up correctly. You don't want the rear wheel to fall off...

    Edit: hmm, looks like I'm reinventing the wheel by writing this...
  3. Thanks RB for that list - apart from the lack of a split pin the Vtr250 is exactly the same sooooooo I've twice adjusted the chain and twice got the same problem so I don't think I'm hijacking. The first time was when the chain was at the end of its life and second on a brand new chain i.e. its first re-tensioning experience. The chain was pretty tight when it was put on and it has indeed stretched during the first two thousand of its life.

    I don't know how many turns to tighten the two tightening nuts. The first time I did it the chain was pretty hot (after a 100km ride) and the second time it was cold. The second time (the other day) I only tightened the nuts half a turn each and that seemed to take most of the slack out i.e. it was too tight. So I backed both off a quarter of a turn effectively only then tightening each one up a quarter of a turn. I then rode it 400km and it is still like a fish's asshole. So probably I'll take out the quarter turn I put in and be back to square one but with a tightish chain.

    Something is going on that I don't understand.

    The only other point I can add is that both times when I started the tightening operation I was able to untighten the tightening nuts by hand (not the locking ones), which maybe able to be explained by the chain stretching.

    btw I've just ridden from Sydney to Mackay, from where I am now typing, in 5 legs and had a ball.
  4. Another tip when adjusting chain is to measure the slack of the chain when you sit on the bike (or whatever your manual says). If you adjust the chain without getting on the bike you will notice that when you sit on the bike the chain will tighten even more and if its too tight there is always a chance of your chain snapping.
  5. cheers... bookmarking to read this later.
  6. Yeah, over tighten = bad idea
  7. as jimboss says, to see how much slack is needed get someone to sit on the bike (off the stand) and feel the chain. as the suspension compresses the chain tightens.

    with your full weight on the bike, every time you hit a bump the chain will tighten up even more momemtarily. you need enough slack so that at full suspension travel the chain is not 100% tight. if it's too tight it will be stressing the chain, your gearbox, and restricting proper suspension travel.

    hope that gives you an understanding on why the chain needs adjusting.
  8. Well, I got my wife to sit on the bike and the chain couldn't really have been any tighter. So I slacked it off to the point where I'm now happy with the chain tension but I have no idea still why the effect of half a turn would have such a dramatic tightening effect. My logical conclusion is that it has something to do the with tightening/untightening of the axle nut.

    It is of interest (to vtr250 owners perhaps) that I had to switch over to reserve at 242km (with a freshly tightened chain) as a opposed to the more normal 265 +km., indicating that a too tightly tensioned chain has a detrimental effect on fuel consumption (a reasonable extrapolation).

    So to summarise, I tightened it up and backed it off at least the same amount and I know have a chain that is 25-35mm slack as opposed to having a chain that was too loose.

    The Lord knows why, but not me. YET.
  9. Now you've learnt how to adjust your chain, now you can learn string-lining to ensure your wheel is straight. Glad to hear you have the slack in the chain too - it was something I didn't know about for a long time :)
  10. :oops:
    I got help with mine last night. I just didn't feel comfortable doing it myself, alone.

    Good thing my dad and two of his best friends are bike people too, and have been for over 20 years... :)
  11. If the VTR tensioner works the same way as the zzr, it wont be hard to tighten the adjuster nut once the axle nut is loose. On the zzr, the axle runs through a block which sits inside the swingarm. This block has a bolt on the end, pointing backwards. The adjuster nuts can pull this block backward to tighten the chain, if the axle nut is loose. To move the axle forward though, you need to push on the ends of the protruding bolt (something I forgot to mention in my first post).

    Here's a piccie from the manual, the 'blocks' are those things down the bottom.

    So if you got through all that, duncamp, perhaps the reason behind you strange tensioning story is that when you loosened the adjuster nut, the axle didn't actually move forward again, and was still sitting back in the 'tensioned' position.
  12. Thanks, rb, that helps with the understanding of the mechanics.

    I've retensioned the chain on both occasions without raising the rear wheel. Perhaps raising it off the ground would be better. Then again maybe just bouncing on the back a bit after tightening the adjuster nuts and before tightening the axle nut would help.

    How much a turn are you guys giving the adjuster nuts?
  13. a good tip is to get the rear wheel off the ground with an axle stand under where the exhaust pipe joins to the muffler (with a rag to stop scratches), adjust the chain, then put a screw driver against the chain and turn the wheel so the screw driver jams between the chain and rear sproket, this pulls the axle hard against the adjusters, tighten the axle nut while holding the wheel, then take out the screw driver and check the tension, if your happy take the bike off the axle stand and recheck the tension while sitting on it. I find if i dont do this the axle doesnt sit right against the adjusters and the chain gets tighter when i do up the axle nut and i have to re adjust it.
    Dont forget to do up the locknuts!
    I never clean chains, i personally dont think its good for the rubber o-rings to spray them in solvent (but each to their own).
    so i just spray it in a good quality chain lube. I like silkolene titanium chain lube cause it doesnt fly off and its white so it makes the chain look new and pretty :). Also it is much easier to lube the chain if you put it back up on the axle stand and spin the wheel while spraying the chain. Ive seen people spray the chain then push the bike 2m then spray it again and push it another 2m and so on and so on, an axle stand is much quicker.
  14. The zzr comes with a centre stand, I should have mentioned that I put hte bike up on that. I find it a lot easier to work when the bike is sitting straight up, without weight on the rear wheel.