New to me, T140 with low compression.. what else to do?

Hi and welcome to the forum.
Someone should be able to help you with this - (just not me I'm afraid).

 

Hi TB.
Check and reset tappet clearance as needed and re-check the compression.
With engine at top dead centre drop a teaspoonful of engine oil in each bore and see if the psi reading improves. If so it may be rings/bore. After honing they may take a little while to bed in, but you readings do seem a bit low.
Stripping the top end is not too difficult - I did it as a 17 year old with a Speed Twin 5TA engine (500cc) so it must be easy, and it ran when I re built it!!
When stripped, check the gap on the rings by removing them from the pistons (carefully!!) and fitting them into the bores to measure the gap between the open ends. You should be able to see the honing marks on the cylinder walls if all is well.
A 'rule of thumb' way of checking the bottom end is to grab each conrod with the crank at top dead centre and by pulling/pushing up and down feel for any free play in the big end - there should be little or preferably none.
Sadly I have no idea what the various gaps/tolerances should be, but I guess you can find them out via google etc.
Don't know what year your bike is but be aware that the very early T140s were 725cc as opposed to the later ones being 745cc.
Hope at least some of this gibberish is helpful!

 

As far as I am aware, there is no particular issue with main bearings on Bonnies. Even the BSA main bearing 'problem' is not necessarily a problem - regular oil changes and respect for the age of the bike appears to enough to keep everything well. Incidentally, main bearings tend to rumble when worn. Big ends knock and little ends rattle. A broken crank is embarrassingly noisy ... but that's a Norton thing! And it did get me home - 2 up!!!
Not too sure how to check mains, although I'd probably try to shake the crankshaft warmly by its throat ... err ... flywheel webs, against the bearings and rotate it to see if any roughness can be felt, obviously with the barrels off. Others may well have a more scientific approach. Primary chain and timing gears may need to be disengaged for all this. As I say, not too sure and by this stage I may well be asking for professional help.
Other forums include www.triumphrat.net (Canadian based) and www.triumphtorque.com may be useful as well (I look in on both) plus www.tomcc.org which is the Triumph owners club site. There may also be a T140v model specific site somewhere on t' web - never felt the need to look meself!
Daft as it sounds, a bit of gentle running (of the bike - exercise is a vastly overrated concept) sometimes will allow components to bed in themselves with no further action to be taken by the proud owner. How lucky do you feel?? Oh ... you as well!! That's a bugger!
Steve.

 

Hi, try Meridion Triumphs on F Book. Plenty of info for all Triumphs T140 is a very reliable bike if looked after very fastidiously and very easy to work on.

Eric.

 

OUCH!!

 

You would certainly get a good answer from the Triumph Owners Club http://www.tomcc.org

But you need to be a member to use the forum. £20 to join. But you do get quite a good monthly magazine.

 

I don't use their forum much myself. But from what I can see the focus seems to be older triumphs.

 

What he says!

TOMCC has been on the go for many years, well before Hinckley interlopers, and as such should have much information about Meriden machines.

Keep us informed about your progress, John.

Incidentally, it's reassuring to know that I'm not the only one who can fall into a bucketful of t*ts and come out sucking me thumbs!! You are a star, TB!

 

It's not EWJ 409V is it? If so I can fill you in on its early history!

 

Not at all sure which grade of petrol suits better. 'Tis a long time since I indulged in BMW-ing (bought mine in Dec 1979!).
General rule of thumb on such matters (lead additives - yes/no) is to run it on unleaded and keep an eye on tappet clearances. If they close up, especially the exhaust side which runs hotter, then the valves are receding into the head and hardened valve seats are needed. If not, then all is well. Ordinary or super unleaded? If it pinks on ordinary then use super.
Yours will probably be okay as I guess it would have had the seats done by now if necessary. And depending on where the 'T' is in the reg number it may well have left the factory ready to roll on unleaded.
Despite having a couple of annoying problems on my RS, I do remember it with some affection. 'Twas a nice bike!

 

I got confused (not difficult, really!) by the mentioning of an R100RS!
The rest of my outpourings will still hold true though ... probably!