916 gearbox problems
 

Hi all. Can somebody give me an idea on this?

It all started 3 days ago when i left home on my 1995 916 and at the first corner i had trouble changing the gear down from 2nd to 1st. The selector was like stucked into 2nd and wouldn't want to move into 1st. Had to stop the engine put it into 1st and go further. For 5 minutes it was difficult to change up (it worked but with increased pressure on the selector), but it was a real pain of selecting down the gears. I'm sure clutch was functioning ok (i have an open cover and i can see it dissengaging). Then, after a few minutes of driving, it suddenly started to work again as normal . I cataloged it as an isolate incident so i ignored it, till...

This morning, left home, did a couple of miles in traffic 1st -2nd gear and while starting off at a streetlight, changed from 1st to 2nd and suddenly a horrible grinding sound was heard from the left side (like the one you get when you miss a gear and it remains somewhere in between gears).

I stopped checked the chain/frontsprocket, everything was ok. Started off in 1st again, it was driveable, but only till max 5mph. Beyond that, the grinding sound appears and the bike simply doesn't accelerate. I tried to change into 2nd/3rd, but all i got was more of the "tool box rattling sound" from the left side if the engine.

I assumed something was wrong with the gear selector/gearbox so i continued at minimum speed till home. 100meters from home things got even worse. When starting from a stop light in 1st gear the bike simply refused to go further, with the clutch pressed and in 1st gear it couldn't be even pushed!!!

I had to stop the engine, put it into neutral (which worked) and push it till home.

With the engine on and gear selected in neutral it can be pushed, but if i select the 1st gear and release the clutch, it seems that the gearbox is seized. 1st gear is selected, with the engine on, it cannot be put into neutral or any other gear (selector seems stuck)

Can anybody suggest potential reasons / solutions?

Regards

somebody? please

Not sure if this helps, but I had a similar problem changing down the gears on my 748.

Happened about 2 weeks ago, I was riding as normal, going up the box was sweet, 2-3-4-5-6, then started to come down the box to 3rd gear, all ok. Caught up with other traffic, tried to knock it down to 2nd. Nothing. It was like the box was already in first gear and you can't go down any further. Know what I mean?!

I stopped for a while, got back on, everything ok for about 2 minutes, then the same thing happened, but this time I was stuck in 5th gear! Not so easy to ride. Managed to limp back to pro-twins and they sorted the problem: disengaged selector rod inside the box. It is supposed to "click" into place as it engages each gear, readying itself for the next gear-change. Mine had come loose, simple as that.

They drained the box, tightened everything, works fine now.

Not sure if this is of help.... :puzzled: Good luck though.

Ade.

Hello CipiVTS

Maybe of no use, was there any sign of an oil light?
Check the oil level, then if me I would drop the oil, check pickup filter.
That would give you a sign, possible main bearings gone. (worst case scenario)

If all ok check the pushrod/bearing.

maybe lose alternator nut has worked lose

does not sound good mate, I had an engine seize on me, and is in bits at the moment.

I hope I am totally wrong, and I am sure some better advice will be along soon.

good luck

regards


TopiToo

[Edited on 15-07-1968 by TopiToo]

Thanks ath748, every advice is useful now. The same happen to me a few days before the incident.

@Topitoo: No pressure light yet (it was the first thing i checked you can imagine:):))

The engine is running as normal while in neutral. The seized engine thing appears after selecting a gear (usually 1st). I tried to select the 2nd but it doesn't get in, although i press the selector as hard as i can

After you press the selector, try to lift it a tiny bit to get it to "click" into place. If that works, then you have at least the same problem as I did. But with the 'box not sounding right, there may be more. :(

Gearchange lever return spring?

From the exterior it seems the lever returns... but you're right, i can't never know what's under still i crack the leftside cover for a check

Or could even be the fork return spring - remember having similar problems on a Pantah and it was a spring that was the culprit. Definitely worth having a look, even if only to rule it (them) out.

Do i have to crack open the crankcases in order to reach the fork spring?

No mate, just take the side case off and should all be accessible. If you u2u me an e-mail address I'll send you the relevant diagram from the workshop manual.

You can remove the side casing with the motor in the chassis, you will to drain the oill and you'll need a puller that goes on the end of the crank to pull the alternator magnet off the crank.

With the side case off you can check the gear selector linkage, this could have slipped or be worn, if you need the page from the manual to set it up U2U me. if it changes up ok and not down it is probably the selector.

It is a bit of a tricky job without the right tools but can be done if your mechanically minded and prepared to spend plenty of time on it.

Good luck.

In my case the selector pedal can be moved up and down, but all i get is a grinding noise and the gear doesn't seem to be actually engaged

I had a similar problem on my 748, the lever kept locking up when I tried to change down a gear...

If you remove the LH cover (make a puller up yourself from a piece of flat stock steel and some bolts), then remove the flywheel. Behind the flywheel you will see part of the gear change mechanism which consists of a fork with a pin in the middle. The pin has a slot in the end and a locknut.

This pin has an eccentric adjustment on it and there is supposed to be an equal gap between each side of the pin and the fork. It has possible that the pin has rotated slightly causing a unequal gap (it had on mine...).

You will need to remove the mechanism to measure this gap properly, mark the position of EVERYTHING with an indelible pen (including the adjustable plate and the selector claw) this will give you a rough idea of where to start from when you put it back together. There is a line marked on the selector claw, this has to be halfway between the pins on the drum. Make sure you can change up and down smoothly before putting the cover back on.

Use a new alternator nut and torque it to the correct figure using a little bit of loctite.

Let me know if you want any more details. :puzzled:

Good luck! :D

Hi all,

I didn't take the bike to the service yet, but together with a friend who is a mechanic at the local Ducati service, we did a few checks:

1. With the engine stopped he moved the bike around and it changed perfectly up and down through all the gears

2. With the engine on (started into neutral) if you rev it a bit it automatically engages a gear !!!!!!
Even with the clutch pressed it cannot be pushed front or backwards.

So he concluded something is wrong inside the gearbox, maybe some washers/dogs/sprockets broken...

What do you guys think?

couple of questions..

1. when you rev the motor and it engages a gear, which gear?

2. "bike cannot be pushed forward or back", is it trying to turn the motor or is it the gearbox that is locked?

It sounds like you need to get the cases apart and have a look. could be broken selector fork but more likely its broken some teeth off. drain the oil and see whats stuck to the sump magnet. bet you find some gearbox bits

Not then end of the world to repair though and its pretty easy to find a 2nd complete gearbox.

hi,

1. i really don't know cause the neutral light remains on and the selector remains in the same position...

2. It's the gearbox which is locked

I have another 748 gearbox which i'm probably going to fit

Thanks for the answers