Hi Guy's. hope you can advise... just bought a T140 that the guy said had been re-honed, new rings etc etc... don't think so!... anyway.. its low on compression, 100 psi lhs and 80 psi rhs (guess i'm looking for 150 psi or so?)... I know you can get sticking rings and all that so need to take a look... question is... its only done 20K miles... so how far do I go?.. .Should the bottom end be okay at that mileage?.. when it starts it sounds good on the bottom end from cold... hold it at 2K and there are no bangs or bumps.. it does not tick over well as you may expect... and as it gets hot it starts to miss as you roll on the throttle as the compression drops further! Will check valves etc make sure they are not holding open.. you never know what people do with them do you ??... any comments appreciated ref mains and big ends... cheers
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!
Thanks Steve... Yes.. can check the tappets and rings... but was wondering more about the Main bearings?.. do they tend to last for ever?... any idea? BTW.. is this the best forum for the old stuff?.. or if there a better one?... Cheers... John
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.
Thanks for all that Steve, its great info and will take a look at it all. Have posted on rat net already but sure there must be UK sites. With regards to luck, my front diff in my Freelander 2, just out of the 3 years warranty and only 40k miles on it, started to wine on the way back from picking the bike up. Its unheard-of but still going to cost £1k to fix! Nuff said!!! LOL
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.
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.
Yes, thanks for that... Looks like a good option. Sometimes other forums can be better than the club one, but no idea on Triumph. For £20 ill give it a go. I'm a member of the TVR club, and although they have the best monthly mag of any club (wins most years), I still prefer Piston Heads forums for real life experience
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!
Indeed... bad few weeks... I also bout a R100RS that smoked the loom luckily when I was at the sellers... still bought it (price adjusted), but thats another job to do that I didn't plan for
no.. its a T plate..... but i've been playing.... ... all valves being held open... at least 1/2 a turn on the screw to close them.. now all set at 6 and 8 thou and compression at 150 PSI per pot does beg the question of why though... I did nip the head down when I got it to an estimated 16 and 18 LB/FT.. and they did move a tad... but can't see it moving this far.. so guess its been running like this for a bit??... So what are the seats like... and are they sinking?? do they suffer anything in the heads and seats? do you run on std or super unleaded?.. do you add anything??... Can't start her up as my little lads in bed but can't wait for tomorrow >
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!
Yes.. started first kick.. bit of smoke as I've been compression testing... and ran well? If seats go, arn't they usualy the inlet or exhaust and not both (cant remember whitch)?.. or may be someone has had the head off for what ever reason, used a differant gasket, and not set up the tappets?? But strang to have them all tight?
I got confused (not difficult, really!) by the mentioning of an R100RS! The rest of my outpourings will still hold true though ... probably!
