Ducati rebuild. Here I go again

[George]

Hi Ian gear change good up or down. I do have to be deliberate with lever and feel dogs engage and cannot change down two gears without letting clutch out. It is 56 years old will give it respect.

[DBDBrian]

Good to hear you have got in a few more miles George. Re the gear selection issue, I have not up to present found any definitive information as to the adjustment of the eccentric, other than trial and error, as Ian comments.
When I rebuilt my selector box, I pondered this issue. My strategy was to make a jig to hold the mechanism perfectly in line without wrestling with the spring. Then using the eccentric, set the claws dead on centre to the pin, with the detent ball in the neutral position.
I have no idea as to whether this is the correct procedure, but I have covered just over 400 miles since the rebuild, and all gears have continued to select OK to date, without further adjustment.
If you feel it would be of any assistance with your problem , I would be more than happy to post the jig.

Used an old selector box for the pictures of the jig.

P1080389.JPG

P1080391.JPG

P1080400.JPG

P1080397.JPG

[George]

Hi Brian thanks for the offer. Adjustment is correct with lever returning after up or down change. Brake lever has a long travel and I think the main problem is the bloke riding the bike is not operating lever correctly

[Bevel bob]

I have heard it said that you should keep pressure on the gear lever untill after the clutch has been released, Perhaps thats what I'm not doing right ! My issues have been going straight thro 2nd into a false neutral if I attempt a fast change ,and not being able to go back to first if I have to suddenly stop in a high gear.

[Duccout]

The return spring puts a twist on the components and any wear on any of them exacerbates this, particularly the spring holder. The splined shaft can be reclaimed by hard chroming if it is worn.

Colin

[Paul W.]

My previously trouble-free selector developed a similar problem after routine cleaning and lubrication. Shifting up from 1st, it would sometimes jump out of 2nd into a false neutral, or go right to 3rd.
This has been addressed on the forum. The selector shaft needs to be shimmed on the snug side, and don't use too much grease on the detents; otherwise rotational inertia can prevent it from stopping positively. Considering the strength of the detent spring, I was skeptical. But it's true.
Now my lever needs a slightly firmer nudge, but rarely misses a change.

[Jordan]

I have heard it said that you should keep pressure on the gear lever untill after the clutch has been released

That helps if the dogs on the sides of the gears are worn.
The dogs have an undercut angle to make for a more reliable change. They work by pulling them together in the event of an incomplete shift movement.
When worn by more than about one third of their length, gear changes will be unreliable unless helped by maintaining pedal pressure until after the clutch is released.
Reducing the shim clearances at the dogs can improve, but it's a big job, and you need a supply of the shims.

[Jordan]

rotational inertia can prevent it from stopping positively. Considering the strength of the detent spring, I was skeptical. But it's true.

Reducing the weight of the gearbox camshaft might be a good thing to do to this heavy rotating item.
Just whip it out, drill it and stick it back in the crankcase.

The detent on bevel Ducatis just holds the selected position, if you're lucky enough to get it to that position.
There are aftermarket selector boxes that have a better scheme that helps gear changes because there is always a tendency to want to be in a gear or the official neutral position.
The standard way, the detent is happy enough to stay between any gears!

[George]

An interesting number of posts on gearchange. I think I will will wait until I have finished running in engine and got used to riding bike as it should be rode, not plodding around.