Honda CB125RS/D 1985

Discussion in 'Motorbike Technical Discussion' started by richard.ingall, Aug 21, 2005.

  1. hi everyone,

    just completed complete motor rebuild on the 125, including rebuilt
    crank, piston kit, geabox bearings and complete top end.

    Motor still sounds like the big-end has gone, even though it's
    brand-new........HELP!!!!!, this is the 3rd time it's been apart, I'm
    obviously missing something (like a clue), but have now drawn a blank.

    Any suggestions (other than the crusher)?


    richard.ingall, Aug 21, 2005
    1. Advertisements

  2. richard.ingall

    Brian Guest

    When you say complete top end , did that include Cam Chain?
    Also Cam Chain tension ,as if its not tensioned right the chain flaps around
    to much and can rub in places causing noises like you describe.
    I've had a few of these bikes and the Cam chain has been a problem on all of
    them .
    I dont know if they had automatic tensioners on any of these bikes but mine
    was a manual tensioner .And if you rebiult the top end you had to retension
    the cam chain every 200kay's or so early on then after the chain seated into
    the new tensioners you could leave it for every oil change or a couple
    thousand kay's or so.
    I hope that helps.
    Brian, Aug 21, 2005
    1. Advertisements

  3. thanks for the reply Brian, unfortunately, virtually the whole of the
    top-end is brand new apart from, literally, the casings. All cam chain and
    valve gear, including the cam are brand new.

    I still think it sounds like big-end, it was the one thing I didn't check
    when assembling the motor, simply due to the fact that the crank was rebuilt
    by local Honda dealer, so I expected it to be right.

    Might turn out to be an expensive oversight on my part!
    richard.ingall, Aug 21, 2005
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.