Big Crunch in gearbox or clutch..Then Back wheel locks up!!!

zxrdave · Post by **zxrdave** » Sat Mar 11, 2006 11:46 pm

Well..first i heard(and felt!) some horid crunching noises from the gearbox, which seemed to stop after afew seconds, so i tried to limp it home(very late, very cold).
As i limped away from a set of lights, changed into third(maybe second) then BANG!!!
Back wheel locks up solid. I(and my pillion!) dragged it of the road.

The selector moves a little but wont engage anything, by pulling the clutch in it will start and sounds fine, (but back wheel is still locked).On releasing the clutch it doesnt seem to engaging anything but stalls straight away like the stand is down.

If it had happened about 10mins before it could have been a 100+ lock up, complete with pillion, it was bad enough at 30mph.

Any help & ideas would be much appreciated, thanks all. ZXRDAVE

Post by **masterofinsanity** » Sun Mar 12, 2006 10:48 am

bloody hell you were lucky, whats the chain like? may have snapped or come off inside the sprocket cover and jammed up? failing that could be the clutch or even worse something inside the gearbox.

zxrdave · Post by **zxrdave** » Sun Mar 12, 2006 1:49 pm

Hi Masters, Yeah, it could have been very nasty. I've just removed everything from the clutch side and all is tip top, nothing locked up. Which is bad news as its got to be in the gearbox.
The main output shaft is stuck solid. So it looks like engine out now.

Does anyone know if you can just turn the engine upside down and split the cases? or do you have to remove head, barrels etc. I think ZX6's can be turned over and the gearbox removed but ive got a feeling its all gotta come apart with the 400.

The bikes just done 20,000mls,'94 UK model. And its just had a new chain, thats fine.

Post by **cargo** » Sun Mar 12, 2006 5:23 pm

I've got mine apart right now and at a guess I'd say yes you can turn it upside down and get into the gearbox.

I think if I was going to do that I'd remove the camchain tensioner to stop the tension in the camchain trying to lift the crank? When you split the cases. But be carefull the camchain doen't move on the crank/ sprockets

Does that make sense???

zxrdave · Post by **zxrdave** » Sun Mar 12, 2006 5:37 pm

I have been offered a good short engine (needs my barrels and pistons + head fitting to make it a goer) but I need to know how much a gasket set would cost any one know? I bet the kwak original would be loads a money.

Where do you lot buy your gaskets from.

Post by **masterofinsanity** » Sun Mar 12, 2006 7:02 pm

think i paid about Â£35 for my head gasket, just the gasket, have a look on ebay?

mongo · Post by **mongo** » Sun Mar 12, 2006 11:28 pm

masterofinsanity wrote:think i paid about Â£35 for my head gasket, just the gasket, have a look on ebay?

They are about Â£17 from the dealer (when i bought mine a couple of years ago).

No you cant get access to the gearbox from the bottom, you need to take the head off then split the cases in half.

If you get the other engine and it needs your barrel and pistons etc, you will have to put your big end bearings and shells in from the crank also. So i would pretty much use the other engine as spares and just replace the gearbox in yours.

zxrdave · Post by **zxrdave** » Mon Mar 13, 2006 8:19 am

mongo wrote:
If you get the other engine and it needs your barrel and pistons etc, you will have to put your big end bearings and shells in from the crank also. So i would pretty much use the other engine as spares and just replace the gearbox in yours.

The other engine has got a good crank in it, the bottom end including the gearbox is guaranteed sound.

Why would I need to put my big end bearings in it?

kris-cross · Post by **kris-cross** » Mon Mar 13, 2006 10:45 pm

You can definitly remove the gearbox without touching the topend. As you correctly say turn it upside down, but firstly remove the bolts from the top crancase ( there are 3 under the starter motor) and about 8 others. Gasgets are as follows approx... head Â£15...clutch Â£12...generator Â£10...pick-up Â£4...sump Â£8
Oh! and as cargo says remove the cam chain tensioner.

zxrdave · Post by **zxrdave** » Sun Mar 19, 2006 1:34 pm

Well ive got it apart and theirs teeth everywere.
Before i got it apart someone told me they would put money on it being a circlip broke or come off, enabling the bike to use 2 gears at the same time! And it looks like he was spot on.
Hopefully get the bits in the week, ready for next W/E.

All i need to do now is put the teeth under my pillow and hope the tooth fairy leaves the money to pay for all this

Has anyone else had anything like this with their 400 g/box?

twids · Post by **twids** » Sun Mar 19, 2006 6:03 pm

just a thought zxrdave .

That new chain wasn't too tight was it?

RedexRobB · Post by **RedexRobB** » Sun Mar 19, 2006 8:15 pm

You'll wanna fluch that engine out before you start it too. Gonna have bits of metal verywhere.

richie400ss · Post by **richie400ss** » Sun Mar 19, 2006 10:32 pm

you want a complete set of gearbox internals?

perfect nick.

Â£50 plus postage.