Tachometer angle drive and camshaft : how does it work ?

[froggie]

Maybe a stupid question but I confess that I do not understand how the rotational movement is transmitted from the camshaft to the axle of the angle drive.

I have bought a mechanical tacho and a bevel cover with an angle drive for my 750 GT.
Here under is shown the internal face with the end of the axle that is supposed to be rotated by the camshaft through a cross-pin piece:

I know that a few pieces are required to link the angle drive to the camshaft inside the bevel head, according to the spare parts catalog:

They include :
- a small slotted disc (92.050) ;
- a bush (49.240) ; and
- a cross pin (98.030), which looks to be the main piece to transmit the rotation.

Before opening the bevel cover and attempting to install the pieces, I would appreciate advice and tips on how to proceed.
Because I do not see an adequate central slot at the end of the camshaft and I cannot understand how the rotation of the camshaft can transmit the movement to the cross pin !

Comments welcome!

[baddean]

That last picture you show with the bevel cover removed appears to be the vertical head.
The mechanical tach drive is driven off of the horizontal or front head cam.
The vertical head has no provision for driving the tach.
The parts diagram shown is of the horizontal head. The parts you indicated would be needed to drive the tach cable and most likely are not there if you have an electronic tach.
Remove the bevel cover from the horizontal head and start there.

[froggie]

Thank you, the answer I expected!
Yes indeed the picture corresponds to the vertical cylinder head cover that I had removed to install a glass cover.

I thought however that the two cylinders were alike as they do not show any difference of the camshaft ends in the parts catalog (difficult to see the details in the drawing but apparently the two camshaft ends only have a sided slot...):

When I disassembly the bevel cover of the horizontal cylinder, I hope that there is that required central slot at the end of the camshaft!

[baddean]

froggie,
When you remove the horizontal/front cylinder cover the cam end should look like the rear/vertical cam end.
You still will need the three pieces/parts shown in the parts diagram to assemble on the cam end to transfer rotation to the tach drive.
What I don't know is if Ducati assembled all of the engines with the parts needed to mechanically drive the tach then simply wired them for electronic tachs leaving the mechanical parts in place.
All of that said, if the front cam end looks like the rear cam end you'll need the three parts.
What does the outside of the tach drive cam cover look like? Is there a small roll pin holding the drive in the cover?
I don't know where you are located but EBay has this available.
The three parts you need depending on the tach drive cover you have.
If the cover you have is molded to the tach drive these parts won't work.
https://www.ebay.com/itm/183893763136?i ... xyp-BSKcn0
Sorry, it didn't occur to me that Steve might have these as well, but I couldn't find them on this site under parts.

[froggie]

Hi baddean,
Just seeing your response now, thank you for all the useful comments and infos.
Here is a pic of the outside cam cover that I purchased, it is the older model provided for early 750 GT's:

It is different from the molded cam cover fit on later 750 GT's and SS's.

Incidentally it seems that the internal cross-pin and sleeve are different between what was installed on single bevels and twin bevels, the later pieces (for twins) looking to be of a longer size even though the tach drive and cam cover of singles look to be similar to those of early twins.
Maybe the overall distance between the tach drive and cam axle was shorter for singles.
Very difficult also to sort out the right reference numbers, it seems that Ducati has been playing with those with time...

Here are pictures of what I found for the twins:

While here under is the shorter version of cross-pin fitted on singles:

Btw, I am in Belgium.
The pictures above come from a web site located in Germany, desmo-shop. Seems that they have some of these parts, I will inquire.

[baddean]

froggie,
Looks like you are on the right track now.