Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

CB250 Chain.....is it loose...if so how do I fix it???

Discussion in 'Bling and Appearance' at netrider.net.au started by CB250_Newby, Apr 1, 2008.

  1. Hey All

    Currently my bike has been odd and when I take off or at high speed it seems to slip or crunch...it is ok at medium speed..but not low or high. Is this a chain problem?

    It is my first bike and I will only be keeping it until the mid year so I don't really want to have any work done to it. Is there anyway I can fix this myself without special tools. I realise this may have been covered a million times so sorry for asking, but I am a total newby.

    I looked at this:


    But I am still not sure as I am not the mechanic type.

    Anyway thanks in advance.
  2. How long have you had the bike? Have you been adjusting the chain?

    The chain needs adjusting approximately every 500km's, and lubricating lightly but frequently.

    To check the condition of the chain, look at the sprockets. The teeth on the sprockets should be smooth rounded hills. If they appear sharp and pointed, hooked or broken your chain and sprockets need replacing.

    There should be no tight spots in the chain. To test this, put the bike on it's cetrestand with the chain properly adjusted. It should rotate freely. If you meet firm resistance at any point you need to replace chain and sprockets.
  3. #3 kols_kebabs, Apr 1, 2008
    Last edited by a moderator: Jul 13, 2015
    You edited your post while I was typing my reply...

    You need to learn to adjust your chain. It's very simple, not a real mechanical job.

    That netrider explanation is unnecessarily complicated. There is plenty of good instruction on the net on how to adjust your chain. Google.

    This video is the closest I could find to your bike.

    The only difference between the GT250 and your CB, is on the chain, in front of the adjusters you have two locknuts that need to be loosened before you can adjust the wheel. I also wouldn't follow his method of looking at the markings on the swingarm to determine if the wheel is in alignment. I find them hard to read, Instead I make sure to strictly turn the adjusters on the left and right of the swingarm the exact same number of turns.
  4. Ok sounds great I will review the video tonight........I have done about 2-3k since I bought it so by now it must really need adjustment!!!

    thanks for the help
  5. If you're in Melbourne, we're doing chain and sprockets tomorrow at spanner night.
  6. Nah unfortunately i'm on the West Side (I will update my profile) I am sure I would fit in at a spanner night though.
  7. I'm sorry I missed the last one loz .. carb synch wasn't it?
    I'll try make one soon mate. I have a workshop in Dandenong that we could use for one of the upcoming nights.
  8. Get the bike on the centre stand and check the free play of the bottom run of the chain about half way between the sprockets. You should be able to lift the chain by about 25mm or similar up and down. If it's very slack you need to adjust it.

    If it's on the limit of it's adjustment, (i.e. the rear wheel is as far back as it can go) your chain needs to be replaced. A loose chain can jump sprockets and lock the wheel and/or damage the cases, or it can damage the bike (or itself) as it flaps around.

    Adjustment goes something like, loosen rear wheel nut, loosen brake torque arm, loosen any lock nuts on the chain adjuster bolts (at the end of the swing arm) while preventing the chain adjuster bolts from moving (you need two spanners). Turn each adjuster the same amount bit by bit, until the chain is at the correct tension. Tighten all bolts in reverse order. I don't know your bike, so the chain adjusters and lock nuts might be in slightly different positions, but the principal is the same. Check the rear wheel spins up easily before you ride off, and make sure all the bolts are tights and split pins etc are in place.
  9. Thanks GPZ1135

    That overview is simple enough for me. I'll give it a go on Friday and let you know how I went.

    Thanks to everyone for their input.
  10. Ok..

    This evening, popped bike on rear stand to tighten chain up.

    Get the shifting spanner out to loosen rear axel & the f*cken
    thing is already loose as, that is, I could unwind it without use
    of tools :shock: :eek:

    Repercussions for riding with loose rear wheel? :LOL:
  11. That's okay, you've got nothing to worry about until the axle bolt slides out... :rofl: :bolt:
  12. None, if you are in one piece.

    The chain will normally pull the wheel forward against the adjusters. The brake would, if mounted above the swingarm, tend to pull the wheel back as it is applied. If mounted below the swingarm it would probably pull the wheel forward against the adjusters, but I could be wrong. It's not something I try very often ;-)

    The axle could eventually fall out one side at least after the nut cam off. You should notice some serious wobbling before it gets that far...


  13. Cheers for that Trev :eek: :)

    Much appreciated.

    Until you posted I kept thinking what couldve been if
    I was on the road :shock:

    Just goes to show ya must always periodically give your
    bike the once over.
  14. :shock: Damn! I've put over 6500 km on mine and its only needed to be adjusted once. And that was only slightly.