Trumph 1940 Speed Twin

[Dougtheinternetannoyance123]

Holy crap, the roller spacing sure is 'interesting'. I'd try and source more robust alternatives directly via bearing manufacturers.

Properly maintained tapered roller wheel bearings can last hundreds of thousands of miles. It's one of the things I love about my '98 Sporty.

The problem is the British used odd sizes that are now obsolete, So sourcing bearings aint so easy. Same with neck bearings, most are little balls in a cup but the machined sizes are all odd. For the steering necks you can convert to a taper bearing and race and use common bearing house parts but you have to machine a spacer for the race. Several places sell these kits ready made but I used to make them for custom builds.

Not quite as easy with the wheels, I have not really tried sizing or sourcing alternatives and in the past just used later model/year wheels instead. But for a restoration or keeping it period correct its something that has to be addressed. The rear wheels is a big problem and I have several projects I need to address this with. The axle openings in the frames on the rigids are smaller and different OD axle, The bearings on the wheels also use the taper bearings. Be nice if someone figures out a source for them but my understanding is really hard to find.

The Triumphs for certain years ALSO used a optional sprung hub, which was a weird design, Big ass hub full of springs, heavy as hell, Allegedly, if you try to take it apart the springs can kill a person and requires a special tool. But the bearings that hub uses are such an odd size they are made of that rare material called UN-OB-TAIN-IUM.

Be helpful to find out some alternatives for the pre 53 wheels

[Fetch]

Great bike. I would split the cases and clean the sludge trap before hanging anymore parts

[Nanonevol]

Good thought but I don't think sludge traps came until about 1960.

[Dougtheinternetannoyance123]

The early 3 piece cranks still have a sludge cavity, They still gum up just like the later ones. But the early cranks were weak and spindly, so were the rods and ran on Babbit instead of bearing shells.
Triumph switched to a one piece much heavier duty crank and added a threaded plug with a tube thats accessible for clean outs.
Many people look for the one piece cranks for preunits and use them instead in early preunit engines as better quality. However a Unit Crank has different ends and wont work. Or at least wont without mods.

(The shock absorber spring is on the end of the crank on early models, later the cush drive moved inside the clutch hub)

It is possible to use all kinds of later unit parts on a preunit, but thats a topic in itself.

[TriNortchopz]

Does your machine have a bronze head?

This is an interesting read:

The Tiger of Picardy
"t isn’t an everyday occurrence, finding yourself in a time capsule house in France, looking at a 1940 Triumph Tiger 100, sat parked in a hallway since the 1980s. Prewar T100s are rare — they were rare when new — and given the onset of WW2, 1940 models are very rare indeed. Most were exported to the United States, but a few went elsewhere. This machine in the hallway was ordered new by a Frenchman, who collected it from a Triumph dealer in the northern French town of Amiens, in November 1939...







"...The Speed Twin engine produced 26bhp, or more with hotter pistons and cams. However, the six-stud barrel-to-crankcase joint was prone not just to oil leakage at sustained high revs, but sudden, violent separation as studs were ripped from the alloy. Triumph introduced a new crankcase and cylinder block for the T100 with an eight-stud joint. The cylinder head was also new, with a larger one-inch inlet manifold and polished ports. It was made by the Birmingham firm of Birco, which some say explains the B suffix to the part number: E1454B. Birco also produced the optional bronze head (as fitted to the Rodenberg racer) that cost an extra £7 4s or $36 at contemporary exchange rates. The prewar bronze heads were also numbered E1454B but Birco produced a batch of bronze T100 heads for Triumph just after the war, in response to orders from the United States. These postwar heads were numbered E2258. Some tuners fitted the T100 head to Speed Twin engines as the head stud configuration remained unrevised..."

https://thevintagent.com/2017/10/02/the-tiger-of-picardy/

[Dexter]

Thanks to all the contributions to date some interesting reading.

On the rear wheel its has been reassembled and no pictures but it has a tapered bearing like the fron one side and a centre sleeve and a sealed bearing the other side which was changes as it felt past its best.

No plans to strip the engine yet, from the info I have from the old owner its spent a lot of time unused between races and then layed up before my purchase.

The magneto has been set off and had a broken winding which will explain the poor starting so this is coming back with a full rebuild.

Most of my latest work has concentrated on finishing off both front and rear wheel, I took a long look at the rear mudguard but just hated the proportions of the stays and the guard looked a bit like swiss cheese so I took the decision to replace both which would allow me to change the clearance of mudguard to tyre which I wanted to reduce. I have remade the stays in a similar fashion but with smaller proportions.

Mudguard to frame mount


Stays with a welded extra plate of 5mm added at the end which are threaded so just a bolt required.


Assembled

[Dexter]

Played with the front brake duct - this has been welded on so not the best mod by a previous owner and the square end was not doing it for me so a slight mod.

[Hoghead]

Thanks to all the contributions to date some interesting reading.

Most of my latest work has concentrated on finishing off both front and rear wheel, I took a long look at the rear mudguard but just hated the proportions of the stays and the guard looked a bit like swiss cheese so I took the decision to replace both which would allow me to change the clearance of mudguard to tyre which I wanted to reduce. I have remade the stays in a similar fashion but with smaller proportions.

Mudguard to frame mount
[ATTACH=CONFIG]98102[/ATTACH]

Stays with a welded extra plate of 5mm added at the end which are threaded so just a bolt required.
[ATTACH=CONFIG]98103[/ATTACH]

Assembled
[ATTACH=CONFIG]98104[/ATTACH]

Dexter- are those stays alloy?

[Dexter]

Dexter- are those stays alloy?

Yes alloy 2mm thick with a further piece 5mm thick welded on so its thick enough to be tapped for a fixing ( not yet drilled in these photos ) and also the 5mm step helps to set it off and miss the curled edge of the mudguard

[Hoghead]

Yes alloy 2mm thick with a further piece 5mm thick welded on so its thick enough to be tapped for a fixing ( not yet drilled in these photos ) and also the 5mm step helps to set it off and miss the curled edge of the mudguard

[ATTACH=CONFIG]98433[/ATTACH]

[ATTACH=CONFIG]98434[/ATTACH]

Nice work! I've always been worried about alloy though, for reasons of vibration causing work hardening, then eventual fracture.
Last time I did something similar, I used the tubular steel stays with crimped ends often used on bikes of this era.I like what you've done, though.

[Dexter]

Nice work! I've always been worried about alloy though, for reasons of vibration causing work hardening, then eventual fracture.
Last time I did something similar, I used the tubular steel stays with crimped ends often used on bikes of this era.I like what you've done, though.

Thanks if it do enough miles to brake it I will be proud to fix it.

[Hoghead]

Thanks if it do enough miles to brake it I will be proud to fix it.

Dexter-you are now the custodian of one of the world's most beautiful bikes- it's your canvas, and a fabulous opportunity. Do your own thing always! I'm sure you will do it proud.

[Dexter]

Thanks Hoghead

Refurbed Mag arrived back and is now fitted pretty much started on the first kick so seemed a shame not to get some pictures, its been ridden up and down the road but awaits some better weather to go on a proper road test, also make some new foot peg hangers so this may delay things.....

[Hoghead]

Excellent! The weather has been really crap lately. I had e3134 cams in my old t100-used to pull well.

[Dexter]