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Know anything about a 81 Honda CB900 Custom

Discussion in 'Moto Club' started by Maxthemutt, Sep 8, 2004.

  1. Maxthemutt


    Dec 14, 2001
    Hi, A friend was looking to get rid of this for $100, it's got around 10K on it. It starts but runs very poorly. I've always been an Enduro kind of guy and had no interest in street bikes, but I figured I'd try and get it running better for him. Did a google search of course but didn't find that much. Would like to know anything about it, thanks, Max
  2. Hank Jr

    Hank Jr

    Jul 23, 2000
    Phoenix, AZ US
    A friend of mine bought one new in '82. Nice bike from what I remember.

    CV carbs will get clogged with any and everything. Pull them out and get them rebuilt at a motorcycle shop. They'll need to be synced (all four pulling the same vacumn over the rpm range) after you re-install them, which is, again, something for a trained mechanic to do for you. Drain and flush the gas tank so the same problem doesn't re-occur.

    It has a shaft drive, so chain wear and adjustment are not an issue. However, the shaft and "differential" should be inspected and serviced.

    I don't recall if the valves require adjustment, but a shop manual will tell you and you may want to try that.

    New tires if the old ones are worn or aging badly.

    Change the oil (the transmission and crankcase share the same oil IIRC, else change the tanny oil, too), wash 'er down and go for a ride!

  3. Bullman

    Bullman Deranged Deputy

    Oct 11, 2003
    SW Virginia
    Hank Jr has it all right. Judging from the miles the bike has sat a bunch, and when they do that with gas in them, things get gummed up. One unusual thing about the CB900 Custom is the two speed differential. I am not sure if it is a transmission or a differential oriented, but there is a high and low range in each gear, so basically you have a 10 speed motorcycle. I have a buddy with the 1983 (only year they made them) CB1000 Custom, it is a very nice bike and pretty fast too boot. I don't recall him ever saying anything about extra maintenance or anything, just the standard stuff.
  4. quinch

    quinch Turgid Member Millennium Member

    Aug 9, 1999
    Cool bike, really strong motor.

    For $100, hell yeah, as long as it hasn't been wrecked.
    Dig up a Clymer manual for it, spend a couple weekends working on it, and you have a great bike.
  5. Maxthemutt


    Dec 14, 2001
    Thanks for the replies, I just got it running. It leaks from the two left carbs, hoping a can of seafoam will help.