gear problems

[Romano]

Hi guyz,

its only been short lived that my trx was up and running again.
now the gears wont engage.
last saturday i was riding along did a short wheelie and voila coudnt shift to second stop put it in neutral and then it wouldnt get into 1st or any gear with a lot of jamming on the shifter i got it into second so i could drive home would not shift up or down.
this all started a couple of months ago when it would be slipping in second (similar like a chain would slip over a sprocket)
it would stay in second just slip if is give too much throttle but ride normal if i just took it easy all the other gears no problem at all.
and now its hard to get it into gear.
what can be the problem?
i can get a used gearbox out of the netherlands for cheap (just the gears etc.)
should i start doing this?
im really getting fed up with this bike.
i just ordered the keyster repair kit all the way from australia(motorcycle parts warehouse)
i order a uk style fzr headlamp out of the netherlands.
and then now this pfffffffff.
i really need help and advice.

[cobbadiggabuddyblooo]

Take off the clutch cover and the shift shaft runs from the gear lever all the way through to the sprung mechanism that works on the selector drum in the gearbox. This drum is where your selector forks fit into and slide the gears into place on the shafts.
You'll be able to at least check you have movement all the way to the action working on the drum.

Next in line is the selector forks inside the gear box and that will mean complete dismantle and splitting the cases.

To make things easier, there is no need to remove the rotor from the crank or the clutch basket from the main shaft which are a bugger to remove.
So another couple of $100 USD worth of parts and shipping but you can buy them cheaply from the US as the TDM 850 was sold in the U.S. around 1993. ( go online to partshark in the US )
For that money you'll get the head and cam cover gaskets.
Valve guide seals and cam chain. Base gasket and barrel O rings .
Your 3 engine case gaskets plus the bottom sump/case gasket.
The top sump at the back of the cylinders You have 2 gaskets and you can use the TDM gasket for 1 but the very top 1 you'll need a trx gasket or make your own because the TDM has a different external sump set up.
Do yourself a favour and buy the 5 pair of bottom end shells for the crank/rods and new set of rings.
There's a couple of seals too for the gearbox and you'll have a brand new motor ready to last from years to come.
Just don't over tighten the cam caps on rebuilding...
Have a look at my rebuild thread and it explains how you can work out what bottom end shells you'll need working from the reference numbers on the crank and numbers/letters engraved on the back of the engine case...

[Rod.s]

two things to do first, check that you have the right oil (10w40) and a heaver oil will bind the clutch plates, secondly strip the clutch and check for wear, as you are doing wheelies this will wear the clutch quickly giving the slip you're experiencing.

[alextrx850]

I'd put money on bent selector forks.

[Romano]

thanx guys i will check all your recomendations.
i dont think its the clutch as the slipping was more like a chain slipiing over a sprocket.
not like a clutch slipping.
but i will check the clutch first and take it further from there.
if i need to open up the gearbox do i worry about timing or anything???

[cobbadiggabuddyblooo]

Yes.. Your cam timing.
The only way to access it is to remove the head, barrels, but it may seem a little daunting to start but you'll need a tension wrench when it comes to putting it all back together.
A quality socket set and 1 Allen key socket that fits the nuts that tension the head and Allen keys / screw drivers will do just about all the tasked. As mentioned no need to pull the rotor off the crank or clutch basket and if you look on my rebuild thread, it will show you how to make up a cheap ring compressor when it comes to sliding the barrels down over the pistons.
A pair of circlip and needle nose pliers won't go astray either.

Just don't over tension the cam caps.
If you choose to do it, I'll explain the easiest way to remove the cams and how to re assemble it too.
Don't be surprised if 1 of the top sump bolts snap as it's a common fault but nothing much to stress over.

[dandywarhol]

Before you go stripping the gearbox - can you select gears with the engine off and slightly rocking the bike back and forward to allow the gear dogs to engage? If you can, then the problem is the clutch "dragging"

[cobbadiggabuddyblooo]

Yes good point from Rod and Dandy..
If the bike was sitting for a number of years and if in a humid climate. The oil may have dried out of the fibre plates and perished .

[Tarwetijger]

Yes.. Your cam timing 8<
.

And timing of the balancer shafts, once you get them out. Right?
Or can these be left in place while taking the gearbox out?

[Romano]

Before you go stripping the gearbox - can you select gears with the engine off and slightly rocking the bike back and forward to allow the gear dogs to engage? If you can, then the problem is the clutch "dragging"

sorry for the late reply was reaal busy at work no time for myself at all.
this i had checked last week and yes i can select gears when the engine is off but as soon as i start it its a hell to get it in a gear.
so what do i do to check the clutch for Dragging??

[Romano]

Thanks for the responses everyone as i read the replies im getting hope back that it maybe can be the clutch so i will start with this first any pointer before is start?