T140 progress and thoughts...

Britfan60 said:

Man, you certainly have a way of working with black. Did you powder coat that D grabrail? Love the finish on the forks too. My left cylinder on my D is running rich even though I've tried to lean it out quite a bit. I wish I hadn't had my MKIIs serviced. I was talked into that job last Fall. I had a blown headgasket which was replaced along with the pushrod seals. Remarkably, it was still running pretty good. Anyway, couldn't agree with you more on how lovely and fun the 140 is. I love it. Pretty much a Swiss watch.

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I can’t take the credit, I bought this restored, although I ended up doing a lot of finishing off and ‘tweaking’. I think the satin black is a two pack paint, pretty sure it’s not powder.

Yours really is one of THE nicest T140s I've seen pics of! Would "almost" ... be willing to trade MY own Norton for it, me likes it "so much all the time every day" as my 4 year old Grandson would say

Nice looking bike Eddie
I used to love triumph twins especially the t140 but all the ones I have owned vibrated badly
My t140e was bad throughout the rev range I had a tr7 that vibrated badly and one of my mates had a t140d that was smooth until you got to 70mph
One mate had a t140v that was pretty smooth , well it didn't blow bulbs , break exhaust mounts and shake bolts off as much
My bonnie used to fracture tax disc holders, rotate Speedo and revcounter in their pods
It would regularly blow the headlight bulb and tail light
Also used to shake the 3 pin connector off the back of the headlight bulb
The other issue was the clutch slipping and dragging, although no doubt there are better components out there?
Recently my old t140e turned up at the ace cafe a mate of mine recognised the reg number
The same bloke had it that bought it from me 20 years ago, apparently he never touches it apart from maintenance!!
It was never that reliable when I owned it
Having said all that I would like another one but I'd spend a bit of time with crank balance

There’s good uns and bad uns for sure Baz. I can only assume mine was balanced by someone at some stage.

And of course, you were younger then, as was I, and we were probably a little less mechanically sympathetic than we are now (huge understatement) !

What then should the balance factor be?

Onder said:

What then should the balance factor be?

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Hope you’re not asking me? You’d be better off asking someone who knows what they’re talking about...

I really haven’t a clue any more. There are so many different opinions and also so many different opinions about different balance factors for different applications, what frame it’s in, how it will be ridden, etc.

Triumph said 74% for the T140.

If I were having a crank balanced I’d use the 74% as a starting point and discuss with the balancer and seek their guidance.

If I was rebuilding an engine that I thought was smooth before the strip-down, I would not get it balanced. They may make it worse...

Well you are not alone in giving up on the Magic Number. I realize there are a lot of factors involved. I have two identical motors balanced the same
in two different frames and there is a noticeable difference. That being said I bet even the handlebars you are using introduce hands on differences
(sorry bad pun). Im sure that balance can be achieved in a fairly narrow rpm and load band. You have to know where you want the sweet (or at least
sweeter) to be.

Its a funny ole thing this vibration malarkey.

I think I've only ever had one Triumph that really vibrated badly, and that was a Triton that had the crank balanced by Owen Greenwood!

I did have vibration issues on others, but that's cos I thrashed them mercilessly!

Standard twins I've had have been either OK, or actually very good, if ridden within their limits. The smoothest standard Triumph twin I ever had was a TSS, and that got thrashed mercilessly too.

When I got into tuning them up etc I started using Basset Down balancing and they made even pretty hot rodded engines vibrate no where near as badly as they should have. But Reggie (on this forum) sent his T140 crank them recently and they made a right pigs ear of it!

I have 2 Triumph twins currently and whilst they would not be considered silky smooth, the vibration really is not that bad. I do not know if either has ever been balanced or not (one is a 1968 'light crank' T120, t'other is a 1980 T140).

I now believe that if Triumph twins are balanced to factory spec, and ridden like 'classic bikes' there really isn't much to worry about. I reckon that vibes were only an issue when they were owned by teenage tearaways racing around everywhere and / or not balanced reasonably in the first place.

Well how about using the amount of time you can ride before your hands get too uncomfortable to continue? I had a 73 T140v that ran great but
an hour on the dual carriage and you needed the WC almost as badly as a new set of hands.

Onder said:

Well how about using the amount of time you can ride before your hands get too uncomfortable to continue? I had a 73 T140v that ran great but
an hour on the dual carriage and you needed the WC almost as badly as a new set of hands.

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Praps that’s why they fitted small petrol tanks !

My Triton vibrates quite a lot.

It broke light bulbs, so the lights are now rubber mounted and there’s no more problem.

It cracked the stainless silencers, so now they’re welded to the pipes and rubber mounted.

The alloy tank ended up with ten separate cracks. It’s under the bench now and the bike has a steel tank.

The downtubes cracked and were welded. The head steady tab broke off and was welded back on.

I try to address the matters that arise and prevent the same problem occurring more than once.

Fast Eddie said:

When I got into tuning them up etc I started using Basset Down balancing and they made even pretty hot rodded engines vibrate no where near as badly as they should have. But Reggie (on this forum) sent his T140 crank them recently and they made a right pigs ear of it!

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It is true that my T140 that Fast Eddie is referring to above, does vibrate very badly above 5,000 rpm and it seems to come up through the seat and is very unpleasant. Before sending the crank to Basset Down, I was advised by a well known longstanding Triumph dealership in the South East of England not to send my crankshaft to Basset Down as a crank that they had recently sent had apparently come back looking like a piece of Swiss cheese and vibrating where it shouldn't have. Being a man who makes his own decisions (not very bright) I sent my crank to Basset Down and it came back looking like a piece of Swiss cheese, and it vibrated badly.

To be fair, I had never ridden the T140 prior to having the crank balanced as it was a non-runner, so I can't actually confirm that it was definitively made worse than before it was balanced, and because I couldn't be arsed to strip the engine down again, I never contacted Basset Down about my disappointment, and so didn't give them an opportunity to "improve things," although there wasn't much flywheel left to drill.

Also, I had previously sent Bassett Down a crankshaft from a Moto Guzzi and that engine is really smooth. If I recall, I was told by the Triumph dealer at the time that I referred to above, that the company had recently changed hands.

But I also would be interested to hear of anybody in the UK who has had a good job balancing the crankshaft from a T140, as I would consider another look at this issue.

Reggie, your T140 is a Harris, and should have had the TSS style crank which were more uniformly machined and, generally speaking, better balanced. I had a Harris Bonnie and it only really vibrated badly at, or close to, the 7,000rpm red line (at which it spent way too much time). So, sadly, I would guess that your vibes are Bassets fault.

Before.


After

Fast Eddie said:

So, sadly, I would guess that your vibes are Bassets fault.

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I suspect so too.

That’s an awful lot of metal removed !

I am stunned! What factor did you ask for?

These holes are at about 180* ish from the other set of holes and if I recall, on the opposite edge of the flywheel.
This suggests to me that the crank was deemed to be rocking across its axis as well, but I'm just guessing.

Onder said:

I am stunned! What factor did you ask for?

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I think I asked for 75% and it was apparently balanced at 80%.
Here's the paperwork that I was sent.

Sorry Nigel, I seem to have de-railed your thread.
Hopefully there won't be much to add to this bit.