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what went wrong?

Discussion in 'Bling and Appearance' at netrider.net.au started by OG, Nov 4, 2007.

  1. rained all day i just got out this arvo for a bit of a go as it had started to dry

    went and practiced hill starts for about a hour then on the way home something went wong (btw top of south melbourne market is good to practice hill starts after the market is closed).

    so im at some lights turn left and just after i change gear and give it some gas i hear this wierd noise , i thought the chain fell off or something for a sec. it wasnt a grinding noise or damage sound but sounded like something spinning doing something and making a wierd noise.

    so i coast for a few seconds then go to change up gear but cant , it was like i was in 6th gear and couldnt push it up any more. (wierd if i was in 6th because i was going less than 60 and it didnt feel bogged down or anything)

    so i ended up coming to some red lights half way home and tried to go down to first, the leaver would go down but i didnt seem to be going down gears.

    Now i was in a spot of bother, i tried to rev it a bit higher to see if i could take off in second or whatever gear i was in but it just jolted forward and spluttered to death.

    sigh i took it onto the pavement got off and took a breath had a look and everything looked ok, then i did that thing where you rock the bike and kept hitting the gear leaver down - horray i got it into first

    well after that i ride it for about 15min and everything seems to be ok.

    but i have no idea wtf went on.

    the only thing i can think is when i went up to 2nd it somehow put it in 6th or something and skipped all the other gears.

    I was in a bit of a panic not wanting to push the bike home trying to get there without having to stop at lights but anyone know what happened?
  2. Maybe you fried your clutch doing hill starts? :?
  3. You wouldn't post this in a Tech or maintenance thread ?
  4. because i dont want to know how to fix it i just want to know if this has happened to anyone or anyone can guess what happened.
  5. What bike is it?
  6. As said already, maybe you cooked the clutch
  7. an across 14k's on it

    how would one tell if a clutch is cooked?
    hold the cooking related pun's ;0)
  8. You can only change one gear at a time when pulling the clutch in if you are coasting to a stop or not moving. If not moving at all, you sometimes cannot even change one gear up or down!

    You can also slip in-between gears in places other than neutral.

    It's possible, being a "learner" bike, that the gear lever/selector mechanism has been abused by previoius owners so that the selector assembly is damaged and occasionally missing a shift, or not completing it properly.

    Remember to change only when moving, or if stuck in a high gear, to switch the engine off and rock the bike back and forwards with the clutch out while gently moving the lever down until you find the correct/real neutral.


    Trevor G

    PS What you describe is not a clutch problem - if your clutch was "fried" you would not be able to take off because it was slipping too much. I have never encountered that in decades of riding.

    Equally rare would be the clutch pushrod failing so that the clutch did not disengage at all. Same thing as to rarity of occurrence.
  9. Are you sure about that? So you're telling me one pull of the clutch in and I can only change 1 gear up or down. I can't multi click the gears say from 4th to 6th?

    Don't worry I know you mean one click is one gear its just how you worded it.

    Anyway as for the accross. If it happens again and starts affecting you're riding go take it to a mechanic and explain whats going on. Mind you intermittent problems are the worst.
  10. Ummm I just went out for a ride due to the clear weather...low and behold, this just happened to me while riding back home. Has happened before but I didn't think much of it since it worked fine later on.

    I also have a Suzuki Across... so it might be a Across thing?

    I coast to the lights slowly, changing gears as I go (clutch in, gear down, clutch out). Get to the lights and the lights just turned red so I find Neutral. It finds neutral alright, but I thought about putting it into gear just in case the lights change again. I tried to change it to first but I just see the neutral light go dim and not go away. I tap it down but it's as though it there is a mechanism loose in the transmission that is not engaging the gear changer. *tap tap tap* nothing...I try to get into 2nd and launch from there but couldn't get into 2nd either. At this point I was like uhhh...what the? So I let go of the clutch and rolled the bike up and down (cars behind me probably thinking what the f#@%) and pushed the clutch back in and it changed like normal. Was really weird.

    Got home and tried it again in my driveway while stationary. I hold clutch in and geared up and down to and from about 3rd. Goes up fine, going down was another story. Got into 2nd fine, but then when I try to get to 1st it gets out of 2nd and just gets stuck in Neutral and can't get back out until I let go of clutch and pull it back in.

    Would be wise to take it to the mechanic, but I wouldn't mind trying to fix the bike myself.

    Any suggestions?

    phong =P~
  11. Do you really want to play with the gearbox? This doesn't seem like a clutch problem at all so you'd be digging deep.

    Not sure if those gearboxes are pressed together or not but you'd definately need the right tools and know what you're looking for.
  12. The first thing to do with gear selection problems is to make sure all you external linkages don't have too much play in them.

    Make sure they are tight and there is not too much slop. A little bit of slop can cause big problems.

    Then check your chain slack. It should be adjusted in the recommended range. Too tight or too loose can cause gear selection problems.

    Also, if you have a cable operated clutch, it may be it is not releasing properly. Adjust it so that it is not slipping but it is disengaging as much as possible. It may be on the borderline of not disengaging and then you heated it up with your hill start practice.

    If all those things are right then It's likely to be inside the gearbox.

    The only other area which may cause problems like this is rear suspension freeplay or misalignment.
  13. What you describe is pretty normal behaviour to me. Many gearboxes need a little drivetrain movement to change correctly. Rocking the bike provides that through the chain and sprocket. Letting the clutch out a little to get a little drive does it from the engine end of the drive train.

    You should try a Ducati. Great gearboxes when used right, but it is almost mandatory to be moving when changing gears, or use a little clutch to get the gears to align if stopped. Changing multiple gears up or down while stopped with the clutch held in the whole time: Nearly unheard off !

    So, nothing to fix. Learn how your bike works, and practice better shifting technique.

    The OP may have a bit of a problem with an abused gearbox, but I wouldn't worry about that either unless it happens regularly. It is likely that you didn't change up to 2nd gear firmly, and so the box got stuck between gears, which took a bit a fiddling to sort out. Not to worry. Same advice as above. Be firm with your gear shifts. Check that the gear shift lever isn't set up too high for you. Ask someone (a netrider or during your next service) if you don't know how to check that.
  14. Cool. I'll check the linkages which I think may have some free play. I adjusted the clutch cable a bit and it did help so I haven't had any problems today while riding.

    Thanks for the info everyone :D.

    I usually release the clutch at each shift. It was just this time I thought it might be easier, but ended up being a little bit of a hassle.

    Thanks again.

    phong =P~
  15. First suggestion: read what I wrote earlier. :)

    Motorcycles use a completely different gearbox system (constant mesh) to automotive types (syncromesh).

    Generally a car gearbox can be shifted anytime with the clutch in and the engine running, either stopped or on the move. If the car is parked and in gear it can sometimes be quite difficult to change it out of gear without starting the engine...

    A motorcycle gearbox will frequently not change more than one gear when stopped moving, UNLESS you either let the clutch out somewhat to get the gears rotating or move the bike along (paddle it with your feet).

    It can be quite difficult to do the latter while also trying to change gear!

    The solution: always change to the required gear while still moving, letting the clutch out a little with each gearchange, especially if you are nearly stopped.

    Otherwise what you have both written will occur...time and time again.


    Trevor G
  16. Sorry, that won't help. And even if you could, how would you "Make sure they are tight and there is not too much slop."?

    Sorry again. Maybe if you had a chain-driven gear change, but that is not the case. ;-)

    The gearbox drives the chain and not vice-versa. Even removing the chain completely will not affect the way the gearbox changes!

    Partly true! ;-) Except that the only correct clutch adjustment on the cable is the free play at the lever: the end of the lever should move loosely in and out about 1cm before you start to feel it pull on the mechanism.

    Absolutely right! 100% right, in fact. ;-) Except it's just the way they operate...the way they are.

    <slowly shakes head from side to side> Oh dear, this is terrible, isn't it. And it's not even April 1

    Best regards

    Trevor G
  17. Generally, the system is the same, the money is in the actuator (synchro is just a better designed constant cut, to give the teeth an easier life).

    In your average car box, your gearstick aligns with a gate. In that gate is a rod, you push the gearstick against the rod, and that pushes a selector fork, which pushes two gears together to engage the particular gear.

    In a motorcycle, the same principle applies with the selector forks and gears, however the actuator is a drum with a particular pattern. as you click up/down, you rotate that drum, which pushes or pulls the forks based on the pre-cut pattern in the drum.

    Now, where my knowledge is a bit hazy is the process involved. I gather that what happens, is when you try to move two selector forks at once in a stationary system, as the gears are at different positions relative to each other, and the system is static (i.e. doesn't want to turn), you get selector gears jamming and not wanting to engage/disengage. The alternate to this problem would be to have two selector gears engage at once, which would cause a lock-up of the trannie. You need to move the system a bit (engage clutch) to rotate the gearbox that tenth of a milimetre to "kick" the previous gear off, and engage the new gear.

    Personally, I've had times where everything has lined up perfectly and I've been able to switch from four to one at the lights. other times, I've had to feed power through every gear.

    As for the oP, if the problem hasn't resurfaced again, put it down to the character of the bike. If it does, crack the box open to see what bent and broken bits you pull out.
  18. And there I think lies half the truth. The teeth of the gears in an automotive tranny are always engaged - it is just the coarse dogs which come into and out of engagement.

    Both gearboxes, unlike the implication in my earlier assertion, are "constant mesh" types. I am still researching but it appears that the difference partly lies in the dog/shaft/gear engagement design, and is, possibly, the synchro component.

    On motorcycle transmissions that I have recently worked on there are also sliding gears with engagement dogs cut in the side. There are no synchromesh tools to help engagement in any bike gearbox that I know of. I am not completely sure why a bike and a racing car with a sequential shift can go either way without synchro and without a messy (grinding) shift.

    Clutchless shifts are quite possible in both directions on a bike - the same on a car requires great precision and timing.

    I do know that non-synchro gearboxes (older trucks and tractors that I have driven) will, like a motorbike, not always engage any gear when the engine is off and the vehicle is stationary. I don't ever recall having such a problem with a synchro gearbox.

    In addition, with an old-style crash box, once you miss the correct shift point or don't match the revs correctly, it can be impossible for the average driver to select any gear again without stopping completely, or very nearly. It is possible that this problem is due to the mass/inertia of the heavy flywheels and gears used in industrial applications.

    Motorcycle shift drums can wear, but this is more likely to cause incomplete engagement, with a resultant jumping-out-of-gear condition. This can also be exacerbated by a worn or improperly-ratcheting pawl which is used to produce the one way, one "notch" at-a-time drum rotation.

    The inability to change gears at a standstill is still part of the design - not deliberately done to cause confusion, but a by-product nonetheless.

    The solution? Always change gear while still moving - and sometimes, if trying to go down more than one gear at a time, let the clutch out between shifts to get the gears rotating again to allow the dogs to engage.


    Trevor G
  19. I'm not sure what your problem is here. If your rose joints are worn or the boss is loose on the spline it will make shifting gears more difficult.

    I had a shocker of a bike once that when I bought it you had to lift your foot off the peg. I went round and got the external linkages right and it shifted much better.

    the chain definatly puts a load on the gearbox. ALL the bikes I have owned have shifted rougher when the chain is slack. I have known bikes where the gearbox won't change without load on the chain.

    I'm not sure what you're banging on about here. There is definitely a range in a clutch release where it start to release though to where it is completely released. I was just pointing out his clutch may not be complete releasing by the end of the leaver movement. some bikes it's quite finicky.
    Once again I had a bike where one of the rear shock mount bolts worked loose and the gearbox locked up because the way the chain was loading the gearbox.

    All of the advice I gave here is based on real world experience. I look forward to your apology.
  20. mechanic look at everything told me the gear box oil needed changing
    even though he knew i changed the oil last week, and in the across there is only one type

    anyway rode it to work haven't had the problem again, only thing i could think was some grit in the gearbox ill get back if it happens again