tach drive housing types

[machten]

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Do you know, is that why someone has pasted that red or orange 'I-don't-know-what' on the two drives that I posted photos of?

I've done the same thing on my '68 250 M3D Craig. I used some Araldite to stop oil weeps from pushing past the end disk. Works a treat.

Kev

[Ventodue]

Neat job there, Kev ( nat' ... ).

I see yours is one where the cable drive exits 'upstairs', so to speak. Is it a CEV unit, do you know - i.e. like the first one I posted a piccie of? Or have we found yet another type of drive? (Can't be possible, shurely ..? )

[Jon Pegler]

I can think of at least two more types of tacho drive, Craig.
There is the all in one smooth type, rather like the one in Elderts photo, but with an integral cast body. See photo.
There is also the VDO drive used by Mototrans with 'Made in Spain' cast into it.

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Jon

[Rick]

To help with the original question, I have a 1969 350 Desmo(coffin tank), engine #08364, that came with this tach drive gearbox:

nickel.jpg

These zinc/pot metal housings are the poorest quality of the gearboxes I've seen- this one had an nickel retainer crimped in when I got it- I have another one thats blown out and one good gearbox to mount when I sell the bike.
I'll include a picture of a VDO gearbox- it has AVIS cast in on the other side:

VDO AVIS.jpg

And, what I've heard called a 'Smiths' gearbox- I've never seen a Smiths tachometer for a single, so I don't know what models may have used this gearbox:

Smiths.jpg

And, a photo of the gearbox from an early twin, to show they used some sort of a potting resin to hold the end retainers in- I'm pretty sure this was from the factory like this:

twin.jpg

There may be some late single gearboxes with potted retainers.
My question is on the narrow case tach drive and cover- I think the only narrow case model with a tachometer was the MKIII and later Mark3, and I've only seen them with plain, smooth covers- is that right?
What is the correct tach gearbox for the narrow case models?
Rick

[Eldert]

the pic of my smooth cover has a smiths type drive . i was told you can use a Triumph cable to mate a Smiths rev counter drive a Veglia rev counter

eldert

[Rick]

The triumph cable makes sense- I plan to contact Flanders to see if they sell the ends to make a cable.
A company in Canada makes cables, and it looks like they sell an adapter to go from the square Veglia drive to the flat blade Smiths drive, it's their part #001 on this page:
http://vintagebritishcables.com/Smiths- ... sories.php
It looks long- not sure if it would work with a standard Veglia cable.
The gearbox with the threaded plugs and 2-pin insertion is the nicest one I've seen- would like to know what Ducati came with it.
Rick

[Ventodue]

Well, I got this far before feeling my head was about to explode . Comments/corrections/additions etc welcome, as always. I haven't tried to assign too much in terms of dates or models, so please feel free to say what you think. I'm guessing the first road bike with a tacho would have been the US-market 250 Diana Mark 3 from 1962? (This is where we miss Bob ... )

[Ventodue]

I can think of at least two more types of tacho drive, Craig.
There is the all in one smooth type, rather like the one in Elderts photo, but with an integral cast body. See photo.
There is also the VDO drive used by Mototrans with 'Made in Spain' cast into it.

Ta Jon. The one in the photo, is it the same as the type I posted a piccie of earlier? Or am I missing something?

Do you have a photo of the VDO Mototrans version? Mine is just a plain one ...

[Jon Pegler]

Craig,
The rather out of focus photo I posted of an integrated tacho drive is a different casting to your photo.
There is no grooved edge on my tacho drive, as there is on yours.
It is more like the smooth design in Elderts picture, although it has the standard CEV/Veglia size cable fitting.
I don't have any of the Spanish VDO tacho drives to photograph, but I have seen them in the past.
If anyone has one they want to sell or exchange, I'm always interested.

Jon

[DBDBrian]

I have a bronze drive, “Smiths” type as Eldert suggested, but I don’t know the year. It can be assembled with the output ether top or bottom, enabling the output drive rotation to be clock or anti-clock. Also the caps are screwed in, as Eldert pointed out, far more secure. The cable thread is ½” BSB 26 TPI (British standard brass) as are Smiths drives, with a spade adaptor, A Smiths Chronometric rev counter input flange has a
12 X I mm thread, as to a Veglia I do not have one to check.
My drive / cover were in a bad state all round, I had to make an input shaft, and out put cable flange, plus quite a bit of tiding up. Not being over keen on the coupling arrangement, hovering over the bevel gears,
I made the shaft longer too enter straight into the camshaft.
To insure shaft alignment, I dowelled the cover onto the cylinder head, (with gasket) then line bored the cover through the camshaft bearings, and fitted a sleeve.
I also made the cable sleeve nut, and sent it to J J Cables in the UK, who made the cable to my spec.
It was quite a bit of work, but as Jim said, they are not too thick on the ground.

I have a 9000 rpm 4x1 Smiths Chronometric with the right rotation for the cable to drive from the bottom, which I intend to use.
The only machine I have seen with the Smith type bronze drive, was a 175 Sport, with DUCATII MECCANICA 175 SPORT cast “into” the cover. I would guess at 1958/9.

Brian

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