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Kawasaki clunk or an actual problem?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by drdave, Nov 23, 2007.

  1. Lately I've been having a rather pronounced clunk when changing gears on the ZX7R. Now I am aware that kwaka's have a clunk when changing gears, but I think I may have gone a step further.

    When I change from neutral to first, if I depress the gear lever very slowly, it will either go in to gear (with a clunk) or make several nasty sounds (I think 'crunk' describes it well). Other gear changes ie. 3rd to fourth also don't feel smooth and the feeling I'm getting from the gear lever when changing gears doesn't feel very nice, knid of like I'm forcing it to go into gear.

    Can anyone shed any light on the situation? Will new clutch plates fix me up? Sorry to not supply anymore techinical info but I haven't pulled my clutch apart before and hench don't know how it works!

  2. Nothing to do with the clutch.

    Imagine it like this; your gearbox has two "bits" - one that spins at the speed of the engine through the gears, and one that spins at the speed of your rear wheel when the clutch is out, or stops moving when you pull the clutch in.

    When you go from neutral to first at a standstill, you're sticking a tab from the one that's not moving into the one that's rotating at engine idle speed. IF you don't shove it right in, the tip of that tab will go "TAC TAC TAC TAC" against the spinning slot without going into the slot. That roots your selector dogs, as they're called, like nothing else. Are you the sort of bloke that likes rooting dogs? Didn't think so.

    When you give it a good forceful kick, the tab goes right in, and the output shaft spins the engine-side clutch plates up to speed with the engine, leaving the drive-side clutch plates still until you let the clutch out. It might sound clunky, but your gear is fully selected. The clunk sound is the selector dogs bouncing back and forth a little in their slots.


    Better explanation here:

    Whether or not that paints a good picture in your head, here is the lesson to take from it:

    1) ALWAYS kick your gears in nice and strong, never pussyfoot around on the gear lever
    2) If you want a gearchange to be nice and smooth, try matching revs to your road speed for the gear you're going into - you'll find that as the two spinning bits in the gearbox aproach the same speed, the selector dogs will slot in more and more easily.
  3. +1...

    It also helps with clunky kawasaki gearboxes if you apply a small pressure to the gear lever before you pull the clutch, then match the throttle to the new gear and lightly massage the clutch lever. You'll feel the gear lever pop into the next gear without much effort, nice and smooth, when you do it right. Make sure you continue the pressure on the gear lever until the next gear is completely locked in.

    This is a good technique for all bikes,
    but Kawasakis benefit more than anything else I've ridden.
    It takes some concentration to do the first few times, but you'll get
    the feel of it quickly.

    If you are pulling the clutch all the way in before you start to change gears, then the gearbox slows down and doesn't slide from one gear to the next as easily. CLUNK.

    Also check your clutch cable adjustment if you have one..
  4. Thanks for the brilliant explanation - and I really see how the TAC TAC TAC TAC thing happens.

    However I do my best to match engine speed to road speed yet this still happens. Even when I do forcefully push it into gear the noise and feeling makes me cringe. I guess I liken it to changing gears without the clutch - which I why I suspected the clutch.

    I still think there is something not quite right with it because it hasn't always been this bad.
  5. Let's examine clutch operation.

    1) When you pull the clutch in with the bike in gear (when you are stopped) does it still want to move forward? Do you have to use the brakes to stop it moving?

    2) If no, then your clutch is both adjusted and working correctly.

    Motorcyle gearboxes do not have synchromesh like cars and modern trucks. Hence each gearchange, whether up or down, has to be completed quickly with a positive follow-through, to avoid clunking.

    Preloading as was suggested earlier is also good, but I have only ever needed to do that on a Moto Guzzi.

    Your technique has probably subtly changed - that is why you are noticing a difference. :)


    Trevor G
  6. Have used this technique since someone told me about it just after I started riding. Was especially useful for smooth clutchless shifting on the 250 when I wanted a quick getaway (I've gone back to using the clutch now I'm on the 1100).

    I recommend it to everyone (especially noobs looking for smoother changes), not just Kwacka owners.
  7. :rofl: :rofl:

    Funny sh!t :LOL:
  8. If you're in Melbourne, PM me and bring the bike around, I'll have a quick look and see if it's normal-ish. The other question is how's your chain? As chains wear and develop excessive sideways flex, they can make your gearbox feel awful sloppy. A new chain always makes a gearbox feel tight and slick.
  9. Q: When you pull the clutch in with the bike in gear (when you are stopped) does it still want to move forward? Do you have to use the brakes to stop it moving?

    No, it doesn't want to move forward and I don't need the brake. Sorted.
    So I'll assume --> clutch is both adjusted and working correctly.

    Thanks for the comments and offer for help, but I'm in Newcastle. I will change oil (due anyway) and give the preload thing a go. If problem persists I'll show a mechanic and hopefully the dogs aren't rooted!
  10. If the dogs are rooted, you'll know, because it will start jumping OUT of gear under heavy load.
  11. Just a thought, but when was the last time you changed your oil?
  12. I was going to ask the chain question as Loz did. Then this was my exact question as well.. If the oil has lost its viscosity it will make your gearbox rough as. I had this problem on the ZX12, i hadnt done the k's but had been a couple of months past the oil change date. New oil and the gear changes become as smooth as a kwaka can be.. :grin:
  13. Oil was done about 5000km ago with whatever the expensive oil is they use at Kawasaki garages when it was in for a service. I think this may have been the issue, I changed it yesty and seems to be running much nicer now. I guess I'll just keep changing it every 4000km or so to keep things happy. Thanks everyone for the input.
  14. +2

    I learnt this after a couple of rides on my new bike after upgrading from my old CB. The gear box seems to prefer it when the least amount of clutch as possible is used, goes in nice and smoothly. Unlike the CB which was grab a handful of clutch, bang the gear change and away you go.