South West Bikers | Motorcycle Forum

has anyone worked on or had experience with the gear side of this bike, young lad from yeovil just passed test and got said bike, pulled away as normal bit of a clunk from engine and couldnt find gears easily. went up through the gears to 6th and couldnt get back down, now it stuck in 6th gear??? any advise would be helpfull many thanks andyzzr1100

Wait for Jam to give his expert diagnosis, but sounds to me like you might need to expose the gearbox and have a good look, but could be bent selector fork ? having only ever played with my Gixxer gearbox I wouldn't like to say anything more without a good look.

It sounds like the selector mechanism claw is not engaging with the pins on the end of the selector drum. The clutch cover will need to be removed and below and rear of the clutch basket you'll see the claw mechanism on the other end of the gear selector shaft, there is a spring that provides location for the claw which can break, the front arm of the claw selects the gears on the way down the box, and is held by a light spring which if broken will allow the arm of the claw to fall forwards out of contact with the pins on the end of the selector drum.
My first port of call would be to remove the clutch cover and have a look at the selector claw mechanism.

thanks jam but i checked all that on sunday so stripped the the chain sproket side and removed the chain and sproket, still seized both sides,,, so removed the sump and found 6 to 8 teeth and broken circlip looking at removing engine and turning upside down to split engine so as to get to the gear section easier and replace gears, any advise on this matter would be greatly appreciated, some on ebay at the mo for £25 if that fails prob another engine ??? thanks again,, andy

The chances are the ebay gearbox will be half shagged anyway. Bite the bullet and buy the gears new, that way you will have a good gearbox which will select and stay in gear easily. A secondhand box is likely to be worn on the selector dogs.
You'll need to flip the motor over and remove the lower crankcase half to access the gear shafts, you don't need to touch the top end at all to do this, you will need to get new oil seals for the output shaft, and new side cover gaskets, if teeth are missing then you'll likely need gears on both the input and output shaft.

he`s taken the lower crank case off and said the gears are pretty mashed lol now he needs somewhere to get new gaskets for lower crank and sump etc any ideas would be welcome

The crankcase halves do not have a gasket in between them. You need a high quality sealer. I use either Wellseal, or Yamabond. Suzuki and Kawasaki also have a similar product which is used for joining crankcase halves together. Do NOT use silicone or Hylomar, or Hermetite etc. Yamabond and Wellseal are specifically designed to seal the cases but the sealant does not congeal and potentially block oilways or oil strainers. Gaskets wise I use 3 Cross or Bristol Kawasaki for my Kawasaki parts, both are very good and supply parts quickly. As for the gearbox parts, buy them new, don't buy a secondhand gearbox as the selector dogs will probably be worn anyway.

thanks jam ill let him know, hopefully he`ll listen, but u know what kids are like they know best haha he should of known there wasnt a gasket for the lower crank he took the bloody thing apart as for where hes getting the gears from i havent heard yet, i dread to think though, thers a nice black zxr400 in exeter he would of been better of getting but he wouldnt wait he knew best lol thanks again regards,, andy

Ha ha ha Kids eh! ;)

At least he'll learn from this ( even though he won't admit it ) and tbh how many of his mates can even make beans on toast let alone fit a new gearbox, more useful than a Nintendo high score ...

one of his mates whos helpin him has changed a gear box on a lorry so he knows what hes doing haha

Oh bugger, excuse me while I wipe the egg off my face ....











And I'd have got away with it too, if it wasn't for those pesky kids !!!!

Changing a lorry gearbox, has no bearing on whether he can rebuild a bike engine correctly.

jam wrote:Changing a lorry gearbox, has no bearing on whether he can rebuild a bike engine correctly.

But it'll make him a great TT rider!!!!!









For those who don't get it, did you realise Guy Martin is a HGV mechanic - I don't think he's ever mentioned it.