Chronometric Speedometer

[Sesman]

Nearly done. Just waiting for a new bezel… If you thought rebuilding a SOHC motor was stressful, have a go at a 60 year Chronometric!!!

[McCabe-Thiele (Ted)]

Showing my ignorance, were they the click Speedos as fitted to my old Triumph Twenty one VRM 102 ETF still comes up on the DVLA database.

[Sesman]

Yes, Ted. Chronometric, the sampling type that ticks and down.

[McCabe-Thiele (Ted)]

I always loved that movement, like a Rolex watch.

[Sesman]

But with none of the Rolex accuracy or durability🤨. The cost of these things is escalating now. Very expensive, but novel paper weights in a paperless office😁

[taysidedragon]

It looks good. Quick work too. Well done. 👍

[Johnny4428]

If that’s the one that was on here a few days ago Phil that’s a great job. Take it you sourced the parts you were after for it?

[Sesman]

Hi, Johnny.

Yes, it’s the same one. The spares came from a bizarre source; i’ve relayed the story to your pal who offered the used Chronometric, but I won’t share it here as it’s a bit embarrassing and might offend some folk🫣. I turned the offer down as I didn’t want to butcher a complete, working unit just to preserve the authenticity of my own.

It’s been hell of a battle. The timing mechanism was quite easy to strip and reassemble, but the odometer and trip tumblers were a complete nightmare and really need special tools and methods. For example, to reassemble the trip tumblers I had to insert the pivot pin from the opposite direction, assemble the tension spring, spacers and trip tumblers in reverse order, extract the pin without disturbing anything then reinsert it from the correct end! It took about 5 attempts to succeed. Talk about tricks and tips I had to learn that for myself🤨


I can’t find replacement number strips anywhere, though I have a solution in the making. I was lucky as I managed to source some spares from a very friendly lady at Timeless Motorcycles.

[Laverda Dave]

Very nice work Phil.
Is this going on your Triton or your RC30
Can you share a photo of your Triton please, I like to see Triton's being so individual.

[McCabe-Thiele (Ted)]

But with none of the Rolex accuracy or durability🤨.

There was me in 1965 thinking my Twenty One was such a fast bike as it cruised along the A6 at an easy 90 mph. It was probably only just touching 70 mph if that! ☹️☹️☹️

[Sesman]

Hi, Dave.

No pictures just yet as the project is in an early (very early) stage of evolution. I’ve been steadily acquiring parts such as 750 conversion, upgraded oil pump, new E3134 cams, refurbished R followers, new 30mm concentric carbs, plus all the gubbins for a full engine rebuild including cam bushes; I’ll have see if I can borrow a reaming tool from somewhere.

I’ve also ported the head and had it straightened (skimming these old heads is a real no, no). I’ve also purchased Bob Newby Drive and various bits from Andy Molnar such as mudguards and a seat.

I have however fully rebuilt the short road holder front end with new parts throughout.

I’ll post some photos after I’ve modified the frame to mount the Manx style seat.

[Sesman]

C’est fini…By far the most difficult restoration task I’ve ever completed.

[McCabe-Thiele (Ted)]

That looks as good as new Phillip, respect.

[Sesman]

Cheers, Ted. I will absolutely not consider doing another in that level of detail. It took about 6 hours and cost £50 in parts. Its the worst 6 hours of restoration time experience, but the best £50 I’ve spent.

Next time I’ll get the pros in and go for a long walk at the coast.

[Laverda Dave]

Hi, Dave.

No pictures just yet as the project is in an early (very early) stage of evolution. I’ve been steadily acquiring parts such as 750 conversion, upgraded oil pump, new E3134 cams, refurbished R followers, new 30mm concentric carbs, plus all the gubbins for a full engine rebuild including cam bushes; I’ll have see if I can borrow a reaming tool from somewhere.

I’ve also ported the head and had it straightened (skimming these old heads is a real no, no). I’ve also purchased Bob Newby Drive and various bits from Andy Molnar such as mudguards and a seat.

I have however fully rebuilt the short road holder front end with new parts throughout.

I’ll post some photos after I’ve modified the frame to mount the Manx style seat.

Sounds like an interesting build Phil. I replaced the oil pump in mine with a high flow Morgo pump. I had no choice but to have the head very lightly skimmed after the welding repairs to the combustion chamber. Whilst it was in the engineering shop the guy called me to advise the head needed spot machining on the pillars of the head fixing bolts because they weren't flat which meant the shoulder of the fixings bolts weren't sitting square to the face and that was what he thought was causing the head gasket to keep blowing. He said he'd seen the same thing many times before due to countless previous owners not using a torque wrench. Not many people could afford a torque wrench in the 60’s and 70’s and tight enough was good enough!