1978 Bonneville Project

[Iron]

Well, here we go, the last Triumph project. It’s a June 1978 T140V that’s coming apart for a complete rebuild.

Everything will be stripped, renewed, repainted, rewired, rewhatever it needs.
It’s always interesting to see what the engine is gonna need once I get in there. Will the sludge trap be full or will someone have already been in there?

This will be my last Triumph build.
I have a hankering to do a Speed and Science, S&S Shovel but that’s over the horizon for now.

The last three builds (the black T120V flat tracker, the white T140 Tiger TT and this one, boxes of spares, large garage tools etc will be going to auction in the Spring - assuming they’ll take it all at the Haynes Motor museum) Thanks to @Alfie for keeping his eye on that one for us all. I’ll be having a chat with the auctioneers at the October 2025 auction looking to have everything ready for March 2026 auction.
So, amongst other things going on at home, I’d best crack on if I want this one to be ready for the Spring.

[Octoberon]

Another project - hooray! The last one - aww…

[Wessa]

Good luck (not that you will need it) with the build. looking forward to following the progress.

[Iron]

Dismantled frame. Swingarm, stands and brake cylinder still to get off.

Box full of T140 and engine on the stand. They aren’t getting any lighter…phew

[Iron]

Coninued to take the parts off the frame

T140s are ‘oil in frame’ dry sump machines. The backbone of the frame carries the oil. It is pumped from the engine into the top of the backbone, just in front of the seat. The oil cap can be removed to see the oil pumping back into the tank when it’s running to ensure there’s oil return. Always something to check if you are looking to buy one.
The oil is then drawn by the pump from the bottom of the frame through sludge trap into the crank. The oil at the bottom of the frame therefore the coolest.
There’s a metal oil screen there to sieve any large particles before they get to the engine:

This is the plate at the bottom of the frame with the sieve. I would normally expect a large glob of horribleness here. Given that the oil removed was pretty new and this plate has been off quite recently the horribleness wasn’t that bad. However…

The glittery silver particles are not what was expected. Good job I’m climbing into the engine.

This is the cobbled together rear master cylinder design for the back disc brake.
Triumph did try to match the refinements of the new imported cheaper Jap machines but they really didn’t have any chance given their circumstances.

The reassembled rear master cylinder for reference. They are an utter pain to get off and an even bigger massive pain to get back together.

The copper plated spindle is where the rear brake lever fits and the larger diameter section runs through the mounting plate in the frame. The spring can cause the odd bruised and bleeding knuckles when installing.

The now separated swingarm and frame ready for cleaning, sanding and painting.

This bike has obviousy had some work carried out recently. There are some new fixings, a new tank (badly painted with a brush), the swingarm has been out, new oil and drain screws in the forks, stanchions look good, new ignition switch and some attempt to fix the wiring loom.

It is absolutely, in my experience, typical of a vintage bike being sold by a dealer who is saying it’s fine to buy, ride and enjoy.
I’ve NEVER bought a vintage bike from a dealer that didn’t need a complete rebuild. Never.
If you are after one of these or any other vintage bike and you go for one from a dealer be prepared for:

1. not riding it home
2. lots of arguments with the dealer
3. costs for someone to put it right for you
4. buying of a large tool chest
5. spending vasts amounts of money on parts
6. lots of room and time to fix it

I gain lots of satisfaction from rebuilding/customising/farting around in the garage and just sitting looking at my bikes when I go out (rarely) for a ride.
I get that most riders want something else from their bikes. I’m just saying have a think if you hanker after a pretty 60s Bonny.

[Iron]

Frame sanded down and primer applied.

It’s always a lot of a faff preparing a frame. Tempting to take it to the sandblasters to get it done. Admittedly it is a lot easier and not expensive but the blasting material gets in everywhere.
Doesn’t matter how much the orifices are plugged, masked or sealed.
I’ve had these oil-in-frame ones blasted previously but only if they’ve already been done at some point in their lives. It’s easy to tell as there’s sand in the frame. If it gets into the oil the sieve/filters wont stop it and it’ll make mincemeat of engine components.
If there’s any doubt as to whether they’ve been sandblasted in the past the inside of the frame needs cleaning thoroughly and it takes ages to do it properly. So sanding this one by hand. And a right arse ache it is too.

Frame, swinging arm, engine plates etc. all done with primer and a couple of coats of satin black. Will leave for a day or two and then 2 pack clear coat…over

[Iron]

Continuing with cleaning, sanding, painting and clear coating

Megawhatsit zorsts bodies, new rubbers for coils, new footpeg rubbers (that require a great deal of effort to get on - normally achieved with a large rubber mallet), new grease nipples and all that good stuff.

Clocks look better with new paint rather than those ugly rubber holder things. Then lunch…

a cheese sandwich

and a tea. (For those who like to look at pictures of people’s lunch) - the sandwich wasn’t the actual one I ate, it is a similar photo of one from t’tinternet.

Then the elbow grease to polish the tank. The gold pinstripes look pretty good against the black. I make sure that any stripes/lettering/artwork cannot be felt when running fingertips over the paint. I hate being able to see or feel any lettering/stripes on new stuff. Harleys are pretty bad for that. I don’t know what new Trumpets are like. I’ll have a feel when I’m next in Fowlers.

A plan view also showing my new boots. These are multi task work/bike riding/walking/shopping/going out/pub etc water proof boots. I buy them when they are on sale on Amazonium (normally about £60) so always have a new pair in a box in the cupboard as i use these until they wear out or sometimes fall apart.

The very scarce 120/80 by 18 Mezeler Tourance tyre has eventually been delivered from ze Germans (suppliers here were quoting next year!) - bit more expensive but now I can at least start the rebuild before getting on with the engine. Over…

[Dawsy]

All very excellent as usual but your brew looks far too weak

[Iron]

Southern Softie I’m afraid, tea brewed in a teapot, homebaked bread made with Cotswold flour and cheese from Cheddar. I try to support local where I can

[Vulpes]

@Iron

tea

Good for the sickly and elderly.

[Iron]

Yep, I’m both of those

[Vulpes]

It was meant in jest - not having a “tea culture” on the continent…

[Iron]

I seem to have been changing and spacing lot of wheels lately

Swinging arm in with new bobbins etc. Headstock bearings in and forks back on.

[Iron]

Got the most complicated rear brake assembly back together. All standard, people like standard, as Hugh Mackie of SixthStreetSpecials says “the closer to standard, the better they run” or something like that

Had a clean and look at the calipers. Guess what. the PO had put the pistons in back to front! Poo.

Got them out with a bit of compressed air. But have to duck and make sure they’re not aimed at the window as they shoot out.

These are the pads from the front and back calipers looking at the back side where the pistons push on them. You can see how the piston the right way round presses in a circle ensuring the pad uses it’s whole width against the disc. The pad on the right has only been pressed in the centre which isn’t going to keep the pad square or give anything like full braking capacity.

Pistons were in ok condition so cleaned and re-installed.

New split pins and reassembled

And back onto the rear wheel.

Luvly original Spanish Akront rims on this bike now.

Brakes all reassmebled, Stands and springs on. Just put some drag bars on for now so I can push it around.
Done for today, off to watch Kelly’s Heroes again. Over…

[Vulpes]

@Iron

the PO had put the pistons in back to front!

Some people oughtn’t be allowed to work on bikes…

[Iron]

Stuck in a mine field, our Heroes are crawling along slowly feeling their way by sticking their bayonets into the ground ahead of them
Don Rickles’ bayonet hits metal and he cries out in a panic “Hey, hey, hey, I found one!”
Telly Savalas calls back “What kind is it?”
Don Rickles replies “The kind that blows up! How the hell do I know what kind it is?”
Brilliant.
Back to the build tomorrow

[Iron]

Rolling chassis about there…

awaiting s few bits before making up clocks and headlight brackets. Will be moving onto this:

Given the ally sparkles etc found in the oil tank sieve, I’ve no idea what I’m going to find in here. So it’s gonna be sort of interesting to find what’s going on inside.
The engine has obviously been worked on given the allen head bolts and new green coloured gaskets. The oil in the tank was also new-ish.
This is a typical “restore or ride as is” dealer’s advert. Maybe it’ll be pristine inside?

[DCS222]

I hope so, but I know you’ll be teking it apart and putting it back together in a fashion that will cause much drool loss anyway!

[Wessa]

Yes it will be interesting to see what you find.

[Iron]

It may be worth doing a standalone thread on a T140 engine rebuild. I’ve done engine stuff on other builds and even other forums but I don’t think I’ve done a complete engine.
I assume an internet search could then throw up this for any potential future T140 engine rebuilders. Does the internet work like that? Finding threads in forums.
Once the engine is done (assuming I finish it and it doesn’t throw me a curve ball) I can then get back into this thread for the complete bike build.
Just a thought, asking for a friend and all that…