Why did this happen to my speedo drive

[frodi]

The speedo on my R850R died on me two trips ago about 60 miles from home. A similar thing happed last year and I reseated the cable at the speedo (it had visibly come loose) and all was well. I repeated it this time but when I took the bike out for my spin down to Kerry two weeks ago I had no speedo at all.

Tonight with the assistance of the tufted one (OK he did all the work ) we took off the speedo drive to find it full of swarf. Cleaned and disassembled the white plastic/nylon ring which drives the worm drive was chewed up at the bottom. The bit that sits into here.

So any ideas why the bottom of this might get chewed up? One theory we had was that when the cable came loose at the speedo this this allowed the worm drive to move out and push the nylon dowacky out of position and thereby start the chewing up.

The Tufted one did a McGyver job/piece of precision engineering on the old bit and it works after a fashion for now but I still have another one on order from Motorworks.

I'd like to know if there is any reasonable/possible cause so i don't end up having to replace this one as well.

Thanks all in adv.

 

[Steptoe]

Replace the metal pronged speedo drive that sits in the wheel behind the bearing outer seal.

 

[Paul Young]

I would go with Steptoe’s advice, but how old is the cable? If it has dried/stiffened with age, the nylon gear could be the weakest point to take the hit.

 

[frodi]

Bike is 19 years old so I'm guessing that the speedo cable is also 19 years old.

We had a look at the metal pronged ring but decided against doing anything as it could turn the two hours that we had spent into another two or three hours at least and we had no replacement seals.

Food for thought before we fit the replacement one that I've ordered.

 

[Ogmios]

yep, no point in taking the entirety apart if we hadn't new bits to put in.
Actually there wasn't swarf in the parts shown in the pic. I checked very carefully for that. But without taking out the seal, we cant get a proper look in / at the metal pronged drive in the wheel. That seems to just sort of dangle there - loose. Is it meant to?
Also - no harm in packing everything in standard LM grease i presume. (Maybe that would cure the dangling drive?)
Also - i've no idea who this "tufted one" is ~ i never saw him and *I* did all the feckin work!

~~

 

[The Other PaulG]

I'd be straight back to the dealer for a warranty claim. not good enough.


PS good luck getting it fixed.

 

[Ogmios]

I'd be straight back to the dealer for a warranty claim. not good enough.


PS good luck getting it fixed.

Agreed - poor show for a BMW
Thanks for the luck - we shouldn't need it, but ...

ANYhow,
i've oft wondered at the fact that these Bikes have complex electronic fuel management systems, ABS, an electronic Rev counter and ....

... a cable operated speedo

 

[frodi]

I'd be straight back to the dealer for a warranty claim. not good enough.


PS good luck getting it fixed.

I'll have to double check but i suspect that it might be just out of warranty. I know that I should have gone for the extended warranty.

 

[Ogmios]

I'll have to double check but i suspect that it might be just out of warranty. I know that I should have gone for the extended warranty.

But he went for my mechanical skills instead.
A long term Guzzisti that's liable to turn up with a hammer and cold chisel in his tool bag.
*Sighs* ah well - at his own risk.
ANYhow, time for my meds.

Sheeit ~ he's my Apothecaryist!

~~~~
Wibble.