Hi guys, hoping someone can advise.....2013 4t, gear lever shaft has lost its normal 'stops' both up & down the gears. I can still select gears but the lever & shaft continue to move in both directions. It doesnt stop in its usual 'detent' positions and wont return to its 'neutral' position after changing gear...Its internal so its an engine out job but can I get to the gear selector mechanism or the gearbox itself without dismantling the engine first?...any thoughts as to the problem?  

 

Edited August 17, 20242 yr by thall1
missing text

You can download a service manual here:  https://store-c2wf2mdg6g.mybigcommerce.com/content/Workshop%20Manual%202008-2024%20Evo%204%20stroke.pdf

Go to PDF page 29 (3.10 shifting mechanism).  I would be looking at item #1.   It is accessible after removing the clutch casing (no need to have the engine out or dismantle it entirely).

The weld broke on the shift shaft.

thanks guys!... I'll take a look later in the week....any tips for holding the clutch basket while I undo the nut without the correct holding tool??... I remember breaking a clutch basket pillar on a Montesa a few years ago trying to loosen the nut...not cheap so would prefer to avoid that again! 

 

1 hour ago, thall1 said:

...any tips for holding the clutch basket while I undo the nut without the correct holding tool?

Impact gun, electric or pneumatic.

ok ill try that

Weld has broken on the gear change shaft. How do I stop the nut and inner clutch basket from spinning when I put the impact gun on it?

6 minutes ago, thall1 said:

... How do I stop the nut and inner clutch basket from spinning when I put the impact gun on it?

You look at the pictures of the special tool Beta would sell to do the job and improvise something that works the same way.

All sorted now… I just refitted the clutch plates and a quick burst with the gun and it’s all off. 
anyone rewelded the shaft before?

I don't see why you couldn't re-weld it.  BUT... is the weld designed to be the weak link that fails thus preventing more costly damage elsewhere?

I assume a crash on the gear-shift caused the weld to fail.

Because OSSA gearboxes are so fragile, I machine a Nylon washer for the shift shaft that goes between the lever and the engine case. This prevents the shaft from being knocked inboard. No gearbox failures from crashing, but unsure if I have ever actually had occasion to test it.  

I’m not sure if there is. ‘Fail safe in the box … a weld wouldn’t be good for that… anyway mines all welded now, I’ll try and get some gaskets tomorrow and hopefully I’ll be good to go!

 

I’ve got two flats on the guide pin… I’m assuming this is wear?… there’s quite a bit of free play in the gear change shaft linkage which appears to limit the movement for selecting 1st and 4th. Neutral to 2nd and into 3rd seems ok… think I might turn up a new pin with a closer fit. 

Edited August 22, 20242 yr by thall1

ive drilled out the original pin and made a new one to better suit the dimensions on the gear change shaft....all fitted and seems to index the gears better. time will tell!