Triumph T140/TR7

[KungFooBob]

The latest in the series of bikes I think about buying, but never do, is the T140!

I quite fancy a proper classic, yes I know a 70's bike isn't a proper classic to some of the crustys on here, but there's the joint appeal of being able to get one from 1978, the year of my birth.

The T140 stands out because it looks like a classic Brit bike, but had left hand gear change and a front disk.

So the questions for the 'experts' are...

Apart from single/dual carbs, what's the difference between the Tr7 and the T140, you'd think being dual carb the 140 would be quicker, but the Tr7 easy to keep running right?

Do they leak as much as the 60's bikes?

Am I going to spend more time fixing it than riding it (not necessarily a bad thing, I like to tinker)?

Should I just stick with my fake classic Enfield instead?

https://www.ebay.co.uk/itm/194939050865 ... SwvoRiPZUT

https://www.ebay.co.uk/itm/284730191239 ... SwZrliQYRu

[Count Steer]

What a shame. My local bike people do 'classic bike hire' and have a T140, so you could have had a day on one as a try out. Sadly, they've stopped doing 'self-ride' and only hire out for films and events. Uggber. Only just found this out as I was planning to give one of the bikes a nice day out in the sun.

[Le_Fromage_Grande]

The TR7 has a detuned Dolomite Sprint engine

[JackyJoll]

Single carb and the different cylinder head and air filter to suit is the only difference.

I’d say buy whichever model you find a good example of.

They don’t leak as much as older bikes but they quite often start leaking from pushrod tubes and around the cylinder head. And cylinder base.

If it’s pre-1979 and still has points ignition, you’ll either spend an unbelievable amount of time keeping them adjusted, or you’ll just put up with a bad running bike. I expect most of them have electronic ignition by now.

Chronic clutch slip is common. Some pattern replacement plates don’t slip, some do. The ones with cork lining are best.

If you’re a mechanic, the valve timing can be altered to make the bike faster.

[Mr. Dazzle]

If you buy and old bike and you don't have grounds to complain about oil leaks, have you really bought an old bike?

[KungFooBob]

Might be a daft question, do they need hardened valve seats to run on unleaded fuel like classic cars?

Also, this fella reckons he's fitted lower comp pistons to run E5 fuel?

https://www.ebay.co.uk/itm/284730191239

[Mr. Dazzle]

he's fitted lower comp pistons

What a pussy. Sorry, meant to say "sensible chap".

Wouldn't have thought E5/E10 would weigh into the compression argument? If anything, ethanol increases effective RON does it not?

WRT the valve seats. I had exactly the same question and found about 9 million answers on the subject. I concluded I'm not doing enough miles to actually give a shit.

[Taipan]

@Nidge has got a T140 and loves it! At least I think its a T140?

[Mr. Dazzle]

He (Nidge) started a thread about it in the owners bike section. Pretty sure his is a blue T140.

[JackyJoll]

Might be a daft question, do they need hardened valve seats to run on unleaded fuel…?

No.

Also, this fella reckons he's fitted lower comp pistons to run E5 fuel?

The 750 twins were always low compression as standard.

[JackyJoll]

he's fitted lower comp pistons

What a pussy. Sorry, meant to say "sensible chap".

Wouldn't have thought E5/E10 would weigh into the compression argument? If anything, ethanol increases effective RON does it not?

WRT the valve seats. I had exactly the same question and found about 9 million answers on the subject. I concluded I'm not doing enough miles to actually give a shit.

They had valve seats suitable for unleaded long before unleaded appeared in the U.K. There is no issue.

[Mr. Dazzle]

They had valve seats suitable for unleaded long before unleaded appeared in the U.K. There is no issue.

Yeja I've heard that...I've come to the conclusion there's no such thing as a definitive answer when it comes to questions about maintaining these old bikes. Even the official manuals are often wrong.

As above, I'm firmly going with the "not enough miles to care"

[KungFooBob]

I've been 'researching' , the stories are that they fitted whatever they had at the time on the production line.

Some bikes were randomly faster than others depending what cams were available on the day.

[The Spin Doctor]

I'd actually like a US Spec Bonnie... I rode one years ago, and with the forward footpegs, it made far more sense riding position wise than the lower bar UK model.

[Mr. Dazzle]

Mine has clips ons and rear sets. It is, by some margin, the most unpleasant riding position of any bike I've ridden. With the added bonus that the lock stops don't acount for the fact its clip ons so its really easy to trap your thumbs against the tank.

[JackyJoll]

I'd actually like a US Spec Bonnie... I rode one years ago, and with the forward footpegs, it made far more sense riding position wise than the lower bar UK model.

Nope- you got that wrong. Totally sexually inadequate.

[JackyJoll]

I've been 'researching' , the stories are that they fitted whatever they had at the time on the production line.

Some bikes were randomly faster than others depending what cams were available on the day.

Well no, I have found that the camshafts were consistently accurate.

There were problems with alignment of crankshaft, crankcase mouth and bores though.

[KungFooBob]

What is availability of the Les Harris bikes like? Weren't they reputadly put together with a lot more attention to alignment and balancing?

Out of the 30x T140's on t'bay today none are the later Harris bikes. The newest one is a Lady Di special edition from 1981.

The Devon Bonnevilles started in 1985.

[KungFooBob]

I keep going back to this one...

https://www.ebay.co.uk/itm/284730191239

I know it's not very original, but I just like the look of it (including the brown seat).

If my motorhome sells anytime soon, I might go have a proper gander at it.

[Mr. Dazzle]

If you buy one thats in decent nick you're not gonna lose money on it are you, so may as well dive on in.