Clutch noise?

Discussion in 'Motorbike Technical Discussion' started by Willie The Wimp, Nov 9, 2009.

  1. Older CBR600, lo-miles.

    Engine warm, accelerate up hill, maybe 35 mph, in 3rd gear. Reach
    top, dis-engage clutch, coast down hill in 3rd. with clutch lever
    actuated. When I hunker down, I can hear a sort-of growling/grinding

    This is "normal operating noise" for a bike with a wet clutch?

    Willie The Wimp, Nov 9, 2009
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  2. Wet clutch baskets will make a low frequency clattering clunking noise
    at about 1/3 the engine RPM with the clutch lever OUT.

    If you pull the clutch lever IN and the noise goes away, that's the
    clutch basket
    flopping around a liitle bit on its bearings which ride on the
    transmission mainshaft.

    If there is still a lot of clattering and clanking with the clutch
    lever pulled IN all the way, the two other suspects are a loose or
    worn out cam chain, or a starter clutch that's flopping around on its
    Shantideva Upasaka, Nov 9, 2009
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  3. That'll be the chain and transmission.
    It's not the clutch. Not if you have the lever pulled in..
    The Older Gentleman, Nov 10, 2009
  4. Wrong again. Different type of noise entirely.
    The Older Gentleman, Nov 10, 2009
  5. OK.

    A 2nd scenario. I go out the garage, start the bike cold, hold the
    clutch lever in whilst in neutral gear, hear a very similar sort-of
    growling/grinding noise. By the time I roll the bike out the garage
    (maybe 15 seconds), the noise stops. I always try to wait for this
    before shifting to 1st gear (less clunk).

    Normal clutch noise?

    Willie The Wimp, Nov 10, 2009
  6. Hard to tell without listening, but all transmissions and clutches make
    a noise somewhere or other. Just ride it. I don't think anything at all
    is wrong with it.
    The Older Gentleman, Nov 10, 2009
  7. As I said previously, the clutch basket itself has to ride on a
    bearing that allows it to turn at a different speed from the
    transmission mainshaft.

    If this bearing is worn out, the clutch basket can flop around
    radially and it will make a rattling sound until you pull the clutch
    lever in.

    Part of the noise is also due to slight misalignments of the primary
    gears, which are usually straight cut gears.

    Straight cut gears are generally noisy anyway.

    If the big nut that holds the clutch center hub onto the transmission
    mainshaft is really loose from drive train slop over the decades, the
    clutch basket can also walk sideways, along the axis of the mainshaft.

    Pulling the clutch lever on a Honda will usually push a loose clutch
    center hub towards the centerline of the motorcycle, because the
    clutch is build Honda-screwy, it's inside out, compared to Suzuki,
    Yamaha, and some Kawasaki clutches.

    Pushing on a loose clutch by pulling the clutch lever will quiet down
    the clutch.

    On Suzukis, Yamahas, and some Kawasakis, pulling the clutch lever will
    push a loose clutch center hub away from the centerline of the
    motorcycle, stopping some of the clutch rattle.

    Then there is the transmission itself, which has 5 sets of noisy
    straight cut gears, which are all meshed with each other, all the
    time, even when the tranmission is in neutral.

    These gear sets don't have any bearings inside the gears, so they tend
    to be noisy when the engine is cold.

    Also, cold engine oil is thicker than warm engine oil, so the gear
    sets will try to turn the rear wheel, even when the transmission is in
    neutral. It's the thick oil and high idle RPM when cold that causes
    the transmission to clunk when you
    put it in gear.

    You might try putting the transmission into 2nd gear first, to reduce
    the clunk, and then put it into 1st gear.

    I wouldn't pay too much attention to "TOG", who calls himself "The
    Older Gentleman".

    He's not older, and he's NO gentleman. He hangs around on Usenet all
    day to start arguments with people. He'll tell you that he's "just
    trying to help", and that it's all your fault for being too stupid to
    describe your problem accurately.

    He will insult you and argue some more, and try to get you to admit
    that you're the one who's wrong and you'll have to apologize for
    "wasting" his time.

    He's a Usenet troll, this is what he does all day.
    Shantideva Upasaka, Nov 10, 2009
  8. Nope. He's just saying the guy doesn't have a problem. And he's just
    said that all transmissions make a noise of one sort or another, only he
    managed it in rather fewer words than you just have.
    The Older Gentleman, Nov 11, 2009
  9. How do you KNOW that?

    You don't KNOW whether he has a problem with cam chain tension, worn
    out chain and sprockets, a loose clutch hub, bent shifter forks, or a
    starter clutch that's about to lock up and throw him onto the

    You just don't KNOW.

    But I think if you go over to ukrm, you can find a whole bunch of
    Slimey supporters who will be glad to extend this thread to 90 or 100
    off topic messages...
    Shantideva Upasaka, Nov 11, 2009
  10. Willie The Wimp

    TOG@Toil Guest

    You're talking about one of the most tough and reliable[1] bikes that
    Honda ever built. I'd roll with the percentages. The odds are that Mr
    Honda got it right (because he does, mostly), you've got it wrong
    (because you do, mostly), and he's worrying unduly (because a lot of
    newbies do). So I'll say that none of the above is likely to "throw
    him onto a pavement" any time soon.

    If that does happen, though, I'll certainly apologise. Oh, and I
    mentioned chain and sprocket noise ages ago. I see you've decided to
    list it as a possible problem, at last.

    [1] Second gear used to go on abused early ones. Reg/rec failure is
    well documented, and not confined to the CBR6 anyway.
    TOG@Toil, Nov 11, 2009
  11. It's an OLD Honda, maybe 20 years old, and WHO knows what abuse it's
    been exposed to?

    Certainly not YOU.
    A fat lot of good your apology will do him, if he has to take a ride
    in an ambulance or has to pay a huge repair bill.
    Shantideva Upasaka, Nov 11, 2009
  12. Willie The Wimp

    TOG@Toil Guest

    It's still incredibly tough, and I see and play with rather more old
    Hondas (some much older than this) than you do, so I reckon I know a
    bit more about 'em. It may indeed be on the brink of death-dealing
    mechanical catastrophe, but I doubt it.

    Still, carry on sounding your tocsin[1] if it makes you feel better.
    As opposed to paying a huge bill to a mechanic to be told nothing's
    wrong? Think DatesFat.

    <Leans forward over desk conspiratorially>

    Are you really warning him that his gear selector forks are bent and
    about to kill him?

    [1] You may need to look this up.
    TOG@Toil, Nov 11, 2009
  13. better.

    You are dull and black, Mr. Pot, but I am becoming more and more
    mirror-like with every passing day.
    Shantideva Upasaka, Nov 11, 2009
  14. Willie The Wimp

    Dave Emerson Guest


    You are dull and black, Mr. Pot, but I am becoming more and more
    mirror-like with every passing day.
    Dave Emerson, Nov 17, 2009
  15. Take a hard look at the oil next time you change it,
    looking for metal fuzz and powdered bronze. If you've
    got an oil filter that can be opened, consider disecting
    the filter too.

    Tear into it if you see metal or if the noise gets louder.
    Rob Kleinschmidt, Nov 18, 2009
  16. You've seen such condition(s)? What caused it?
    Willie The Wimp, Nov 18, 2009
  17. Willie The Wimp

    Dave Emerson Guest

    Dave Emerson, Nov 18, 2009
  18. My clutch makes noise when it's pulled in. The plates make
    light contact and bang around some.

    I've also had bearing failures.

    When a bearing cage fails, that also makes noise and
    gets worse, louder and more expensive very quickly. That
    kind of failure shows up as metal in the oil. The metal can
    be as fine as flour paste or later on, sharp beebee size
    chunks. Steel can be pulled out of the oil with a magnet.
    Bronze will stay suspended.

    If you're worried, do an oil change and see what you
    find in the oil. Easy way to reassure yourself that nothing
    really bad has already gone wrong. Then just keep
    an ear open for new noises or changes in behavior.
    If you don't already have a magnetic drain plug, you might
    see if there's one available and install it when you change
    the oil.

    Eventually, you'll be due for new clutch plates anyway
    and you can have a better look then.
    Rob Kleinschmidt, Nov 18, 2009
  19. Rob Kleinschmidt, Nov 18, 2009
  20. When engine parts don't get enough oil, they start wearing out. Once
    the wear gets through the hardened outer layers of steel parts, they
    start wearing really quick.

    But we still don't know whether the noise you described has to do with
    chain and sprockets, or if you still have the noise when the
    motorcycle is not in motion.

    An old mechanic's trick is to listen to various areas of the engine by
    touching it with the tip of a long screwdriver and then putting your
    temple against the plastic handle.

    If you don't happen to own a large screwdriver like that, a piece of
    hardwood dowel
    about a foot long works well.
    âÍÁ Á³Õ »Ñ·àÁ ËØÁ, Nov 19, 2009
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