Thruxton Thruxton R Gear Linkage Bolt Failure

I don't know, but I would be surprised if the ball was ever removed from the socket, cleaned and re-greased. You might find a service schedule with it listed but at best I'd expect a mechanic to inspect the joint for play and replace as required. I'm not sure that you can even lift the rubber boot enough to give it a squirt of grease.

As pointed out on the other forum link you posted, someone said it's not a bolt. It's a ball joint, with a thread and hex, so the tolerances will be different to a bolt. I've known plenty of rod ends bearings in motorsport fail because, when the lock nut comes loose, the play in the thread allows too much movement and it'll either undo itself or snap.

If for instance the locknuts on the little gear change rod linkage we are looking at here, between the two ball joint ends, came loose at either end, it would quickly fail for that same reason.

My key point was that unless a spanner is used that is no thicker than the hex itself, it is easy for a home mechanic to assume the "bolt" is tight when the spanner gets pinched. If the hex is not torqued against the lever, it will only ever be finger tight. No amount of locktight will "glue" that thread in place when put under the loads it recieves. Every gear change and every stamp on the lever to find first gear etc, will rattle the "bolt" thread in the lever and it will come loose and then shear every time. The strength only comes from the length of thread screwed into the lever and crucially, when the hex acts as a locknut, as intended, when it is tightened against the lever.

 

Fair to say that you've been unlucky with this bike. Sorry to hear of your latest issue.

 

Yes it was the bolt that sheared. In my opinion it is a design/manufacturing fault. Touch wood I’ve not had no further problems.

 

Manufacturing defect, no possibly not but could still be an assembly issue.

I would contact the factory and ask if there would be any assistance with this matter.

I did when a wheel balance weight removal took out a chunk of powder coating. The wheel was 510 mile old and straight after 1st service I changed the OE tyres.
They supplied a replacement wheel on an exchange basis, couldn't fault Triumph (or Cobb and Jagger's, the dealer) handling of the matter.

 

Obviously wasn’t reassembled correctly after the bike went over on the left hand side!

 

When I said torque, I was explaining the issue Timboo as like you, I haven’t found a torque value anywhere and nor do I have a tool for that job.

Torque as in tight enough, using a spanner. I do think there was an assembly issue as when my bike was first out in 2019, there was a spate of gear shift link failures. I’m not sure they used threadlock or maybe the wrong one. Whatever I did has lasted about 4000 miles anyway. But mine did need thread locking and tightening from new.
Putting in a claim on that basis is another issue though.

I use nail varnish and nail varnish remover or acetone to wipe it off. It’s basically the same thing but cheaper and easier to get hold of than the official motorsport version.

It’s hard wearing and you can mark things you have torque checked and differs from the white or blue marker that the dealership uses.
It’s useful for safety critical fixings where a quick visual check is all that’s needed.
And sometimes you can see what someone else has touched, or not, at a service etc.

 

Same bolt sheared on a rideout tonight on my 2016 Thruxton R. Identical to pics on here. Did I see that you can just get the bolt after releasing a circlip? Poor quality to just go like that.

 

Surely the bolt that shears can’t be that special? Try SS A2 or A4 -80 which has a higher tensile strength.

 

On the Thruxton and Speed Twin etc, if the ball joint part of the gear lever linkage linkage comes loose, it will back itself out until there is sufficient play in the thread to allow it to move and eventually shear. It only has the required tensile strength when fully tightened with the nut (6Nm) against the linkage face. As noted above, a conventional spanner will jam between the socket part and the gear lever arms and maybe damage the rubber dust seal before the ball part is properly tightened, so you need a thin spanner for that job. And some threadlock!
The same goes for the locknuts on the adjuster rod, also 6Nm, according to the service manual.