Triumphrat

rambo

Mobil 1 20/50 is brilliant in a triumph twin.Wish i could get some in the UK.Last time i was in Florida,i brought some home with me

Snakeoil

The concern that has been voiced by others, although I don't recall any instances where this actually occured, is that the cleansing properties of syn have the potential to loosen up crud in your engine and circulate it thru the bearings, since there are no filters on these engines. In addition, their is thought to be a risk of some large piece of hardened crud coming loose and blocking a key oil port, such as a piece in the sludge trap coming loose.

My personal opinion, for whatever that is worth, is that if you run the bike regularly, you will probably slowly clean your engine a little at a time and with each oil change more old crud will be removed. But if you let the bike sit for long periods, it could have more potential to work at larger deposits without circulating them and when you start the engine after that period, could have a slug of crud run thru with the potential to plug ports and passages.

It's all conjecture as far as I can tell. I don't believe anyone has posted an example of syn oil destroying bearings with crud or old crud coming loose and plugging a port and killing an engine.

And maybe, and I do mean maybe, the apparent lack of cases where syn oil has caused engine destruction or severe damage might very well be telling us that all the concerns voiced, mine included, are just a bunch of hooey.

regards,
Rob

SGOUD

I have added an oil filter on my T140E but again should I change to syn. oil with 10,000 miles on the engine??? Decisions, decisions!!!

loxx101

Very good point!

Considering the opinion is fairly evenly split and 50% of the bikes aren't seizing up... That speaks for itself.

rambo

10,000 miles,its just run in ! If its had regular oil changes,there is no problem.Just make sure its motorcycle oil

thirdbike

The great oil debate for motorcycles continues to pretty much mirror the now passe oil debate for automobiles. Yet even today you're not going to convince the guy that insists on running single weight non-detergent oil in his vintage vehicle because that is what the owner's manual said. Never mind that multi-grade oil was still in development and synthetic oil was a science fiction story at the time of printing.
Running synthetic in your bike is an improvement over running conventional oil. Your bike actually will run cooler as there is less friction. Synthetic oil is more stable and more readily maintains its proper viscosity with changes in temperature which with air cooled mots is more critical. Synthetic oil has uniform long chain molecules that provides a better friction barrier. Conventional petroleum based oils are chemically different in that they are "cracked" from crude oil. As such, they cannot meet the same standard of protection. I should add that you can use automotive synthetic oil in your bike although you may have trouble getting it in the recommended weight such as 20-50. But, if you do use automotive oil, it is very important use an additive such as ZDDP Plus to add the required metals such as zinc, phosphorus, sulphur etc. that especially your flat cam followers require. These metals were removed from modern automotive oils as they affect catalytic converters and emission standards. The only limitation to using synthetic is that you should be using an oil filter. True synthetic oil is less likely to hold most contaminants in solution as opposed to holding them in suspension, A quality oil filter readily removes these suspended contaminants. Also, the type of oil you use should not affect a multi-plate wet clutch. If it slips using synthetic then it slipped using conventional oil with perhaps the only difference being that the conventional oil more likely allowed a contaminant buildup such as sludge to help bind the worn plates (or worn springs). Similarly synthetic oil does not cause oil seals to fail. However, if your oil seals are dried and hardened up having been denied the beneficial lubrication and cooling of the oil because of a sludge buildup and suddenly fresh synthetic oil washes the contaminants away, yes you will get seepage. A seal in good condition with synthetic oil is less likely to leak given the uniform properties of synthetic oil.

brid

"Similarly synthetic oil does not cause oil seals to fail"
Sorry to keep the thread alive - BUT-- putting synthetic in an engine that has lived for any appreciable time on dinosaur WILL create problems - PERIOD. Even modern seals do not like change, and once an engine is 'conditioned' to it's given diet, it will not react favourably to being slapped around
My last comment here, as there are far too many 'lookie loo's' clouding major issues.
Pretty simple really --- If it works - why change?

loxx101

If we all had that attitude we'd still be walking around beating each other with clubs. Not accepting that the way things are done is good enough is why science comes along and indeed why synthetic oil was even invented. It'll get more miles out of my bike before I spend another couple of grand rebuilding my engine. That's why.

What Thirdbike said after the bit you quoted pretty much said the same thing as you!

Seals should be replaced periodically anyway, no matter what oil you use. Depending on the type of seal as well, yes, some oils will degrade them. However, as synthetic/dinosaur oil is all the same thing with a different cleanliness level, the seal won't mind if you change it other than detergents.

Thirdbike, do you have any more info on the metals thing? People always say about Zinc and suchlike but never really know why. You seem like you understand it...

Why do you need metals?

loxx101

This is an interesting article...

http://www.allpar.com/old/oils.php

JohnA

That is an interesting article Loxx. The trouble with online forums is there are so many emphatically held opinions and preconceptions, all of which come pouring onto the page and causing a lot of confusion (and unnecessary worry to some people somethimes). I'm sure the old-fashioned straight oils do have their uses, but on bikes like our Triumph twins, with their combination of plain and roller bearings, a multigrade would seem far more suitable. Then the question becomes what grade, and syn/semi-syn/old-fashioned mineral?

Following this thread has been useful to me. I now know far more about what synthetic oils are than before I began, and I'm convinced that, as my bike has a proper filter, I ought to get hold of some Mobil 1 20/50 if I can. Trouble is, it doesn't seem available in UK for some weird reason. Does anyone know what the next best thing is? Or preferably, where I can get hold of some 20/50?

By the way, what is a Lookie Loo?