900 GTS - Gear Selector Adjustment

My 900GTS has an odd issue that whilst it changes smoothly up the gears and will also change down from 5th to 4th and 4th to 3rd it does not like going 3rd to 2nd and 2nd to 1st.

I have noticed that if you lift the gear shift up a fraction and then try going done it always works.

I thought it might be a weak gear selector spring so replaced it with a new one but it has made no difference,

Can anybody offer any suggestions?

Cheers

Steve

Hi

I posted this ages ago and never got a response.

I am hoping someone might have a suggestion as it is still a problem. Could it be to do with the adjustment screw on the gear selector box? nDoes anybody know how this should be adjusted?

Cheers

Steve P

It’s the lever not quite returning enough to catch the selector drum again.
I have had something similar with my Darmah, I changed the return spring the last time I messed with the clutch and the new one was not quite the right shape it was not quite allowing the lever to return, I sent it back and the new one was OK.
The mechanism is very dependent on the spring centering the lever back in the correct position to allow re engagement with the selector drum in both directions.
Is the centering post tight in the casing (number 31 in the picture)?
If you need to get it apart again, I would suggest dry assembling it with the clutch drum removed so that you can see what’s going on and try it?
Regards.
Kevin.

Hi Steve,
Has your 900GTS got a gear selector box outboard of the gearbox sprocket?
Or is it similar/the same as the exploded parts drawing posted by Kev?

Steve R

Hi

The gear selector unit is housed just inside the outer casing in a separate unit as per picture below

[attachment=0]900GTS.jpg[/attachment]

There is an adjuster with a locknut 21, 4 & 42

Cheers

Steve

Ah, I thought the later 900GTS’s had the same mechanism as the Darmah, I’ve never messed with one… I’m glad to say, they look like a right bodge up!
Kevin.

That was Ducati’s answer to converting the early twin cases to left foot gear change.
I’m fairly sure (apart from the cross over parts) it works much the same as the singles selector system.
The adjuster nut and screw are there to center the pawl, taking note of where you start you could try turning the screw 1/4 turn at a time in each direction to see if it helps.
But your problem could be a worn selector fork inside the motor.
Singles specialists like Nigel Lacey/Lacey Engineering, Brian Silver/Moto Marianna or Tony Brancato/Brancato Engineering would be able to tell you about setting up this system.

Steve R

Hi
Similar problem on my 1981 900SS changes up fine, but lever needs tapping up to change down, I thought it might be the return spring, my question is how do I get to it? Is it behind the clutch drum or do you have to split the cases ( I sincerely hope not!)
Regards Graham

Graham.
It’s behind the clutch drum, so it’ just the left hand casing that has to come off.
The gearchange return spring is worth changing as they tend to last about 25000 miles before breaking!
Whilst it’s off, change or look at the following
Gearchange shaft oil seal, I have found a better one than the rubbish original, I’ll find the details out later…
Ignition pickups have a look at the cables.

Kevin.

Thanks kevin, I found out and took it apart was broken return spring, not sure if I have same problem as you with the new spring i’ve got,as i cant seem to get the gearlever to return to it’s centre position.