Speedo not working

Right - V35 Imola II with defunct speedo. And I think I know what the problem is: Basically the tang on the wheel drive has been bent back so that it is not turning with the wheel. I can see where this occurred as it has made a nice (not) scrape across the part of the hub. Previous owner had just fitted new tyros so I wonder if they were aware of this component?
My question is what to do about it. I can’t see any location slot for the tang, which I would have thought was the obvious way to do it so assume it is just bent inwards so the hub inner spokes move it.
Would that be correct? Is there anything else I should know.
I’ve started looking for a new tang but Gutsibits are out of stock at the moment. It happily looks like some Triumphs use this speedo mechanism so I wonder if there is an equivalent part?
Any advice very appreciated from a new Guzzi owner :open_mouth:

The tangs are very fragile and usually break off. I’m sure someone on here replaces the bit that break off with a bit of tin can.
There should be a notch that it fits into. Cyclobutch should be along soon and will tell you in more detail as he is more familiar with the small block models.
Don’t buy a Triumph one, they are similar but different. I think Nik’s Euro bits on eBay usually has the tangs listed, but they are not coming up in a quick search.

Hi Simon,
Don is correct, they look a bit Micky Mouse, and the drive system is certainly a weak area. the actual drive “box” is very well engineered and manufactured with good quality parts and seals. I stripped one down the other day and was surprised. I would suggest you sort out the drive tang and also spend some time stripping cleaning and greasing the drive “box” and I’m sure you’ll find it will work well for many years to come. I agree that the tangs may have been damaged by not realising how they fit into the spaces between the spokes, however I think you should also check that the cable is in good condition, and not seized in the sheath, as this will also lock up the “box” and cause the tangs to bend when the wheel turns.



Many thanks for that!
I’ve had a good look but I can’t find a notch! The tang has sort of straightened out so no engaging anything (much). Looking at it - it would need to be quite a bit longer to engage a hub spoke. So I can only assume that:
a) A bit has snapped off or
b) I am going blind and haven’t found the notch.
As someone has put new tyres on it it did occur to me that they might have put the tyre on back to front. I guess this is possible with twin discs, but I can’t find a notch on the other side either.
Going to get a cuppa then another look!
Many thanks again!

…just an update! The tang has snapped off.
So it really is get a new tang. Gutsbits list them as out of stock at the moment so I’ll give them a ring and see if they are going to get them. Niks bits sadly can’t get them anymore.
It’s excellent advice to check the box and cable as yes - if siezed or stiff a new tang will go west again!
One area might be an equivalent - the Ducati 20/10 box and tang looks very similar. I’m not bothered if the gearing is out a bit as the bike is an import anyway and the speedo is in KPH so I’ll just re-calibrate the dial with a few useful markers!
Anyway - thanks you for your help!

Sorry - late to the party.

The tang just drives off of the webs on the cast wheel, any of them will do. The boxes are prone to collecting water and seizing, then the tang bends. And once it has done that a couple of times it just breaks off. You want to be greasing it up as part of your annual service routine.

That part is held on with a circlip so just take it off, clean it up and then soft solder a new tang on. A thick bit of a tin can, or biscuit tin which is a bit thicker will do it. Both mine and my pals V50 run like this - works fine.

FANTASTIC! That is what I’ll do. The rotor (if that’s what it’s called) does move around ok but I have no way of knowing what is normal re resistance. Let’s just say it would be a bit of a strain for a bit of thin metal so I’ll deffo service it. The cable is fine!
Thank you all for great advice - worth joining the club already :smiley: :smiley: