Forum

[Bullet Whisperer]

Taking things a step further, I put 20/50 full mineral oil in the engine, gearbox, primary and forks and all work well enough for me.

[Dennis C]

I would agree with you on that Paul, just one thing, the Triumph clutch is prone to sticking if used with multigrade oil, and crunches badly into first gear, Triumph did advise 20 grade to help prevent this but ATF is better.

[Rattlebattle]

Don't you just love oil threads; ten posts, ten opinions (eleven if one of them is an economist....).

[papasmurf]

The last time I took someone's advice as to what oil to use in an engine, the valves burned out in less than a year.

[Bullet Whisperer]

Care needs to be taken with some of the later BSA and Triumph models and their oils - late twins and the triples, as well as the big unit singles were made to breathe from the crankcase into the primary case and vice versa and the primary case oil is self levelling and fed from the engine, with the main bearing acting as a weir in some cases, just like the R.E. Crusaders and unit Bullets [Redditch], although the primary chain sorts out oil return and level for the latter two. I wouldn't put anything other than what the engine is happy with in the primary cases of any such machines, but the basic, original design of Bullet we all know and love has a primary drive which SHOULD be totally isolated from the rest of the engine, so I suppose other stuff can be put in them, but I have never felt the need to do so. Regards, Paul.

[Dennis C]

Rattlebattle you do exaggerate, Papasmurf, it is very unlikely the oil would cause that to happen, but yes another oil thread, yawn.

[Dennis C]

Yes Paul correct again 1968 was the year they did that so a 57 model will be fine with ATF.

[Bullet Whisperer]

Hi Dennis, as you say, your '57 model will be fine with a different grade / type of oil in the primary. Going back to the later ['68 onwards] models, it is also vital to change the primary case oil frequently - I have had to fit new drive side mains in a few T100 s/c machines in recent years, due to dirty, swarfy, primary oil going through the mains on that side. Regards, Paul.

[Dennis C]

Yes just another silly idea, it hard to understand why it was done, the recommended oil change intervals on the early primary case was far more frequent than the engine oil on Triumphs and it really does need changing regularly.

[papasmurf]

Dennis C, in this instance it was the oil that was the reason the valves burned out. It was the only factor involved every thing else on the engine was within specifications.
I learned a valuable lesson, don't listen to anyone who advises putting an oil in an engine than wildly differs from that specified by the manufacturer.