Oil

Now then, nothing like a good oil debate to get us all going eh??

But seriously, Bushman’s great thread on his seized rockers further provoked a question I had already had for some time.

Am I correct in thinking that the factory specify Silkolene oil?

If so, is that what y’all running with still?

I had bad experience with Silkolene breaking down and loosing its viscosity, resulting in low oil pressure. This was using their top synthetic, it was in hot conditions on a highly tuned BSA/Tri triple.

Oil pressure dropped to an alarming low, after checking what I could, I thought my bottom end was shot. But I checked out on line and saw lots of posts claiming that Silkolene degraded quickly, so I changed the oil for Red Line and, bingo, all was well!

I realise that Silkolene (and thus Fuchs) are big companies that should know what they’re doing, so I’m sure their products are good in many applications. But my personal experience of a highly tuned old fashioned air cooled engine, run hard, in hot conditions, was pretty conclusive, and I have since spoken to other classic racers, who voiced similar experiences.

I use motul full synthetic in engine. And motul non synthetic in transmission.

Amsoil Metric Motorcycle 10-40 full synthetic - engine & transmission.

Tried 20-50 in the transmission & clutch and found the clutch grabby - when apart the plates were blotchy, so I don't think thicker is better at least for the clutch.

Motul 5100 Ester 10W40 Synthetic Blend in both engine and gearbox. It doesn't get real cold here in N. Calif and when it gets real hot I don't ride. A great all-around oil. My SE has under 2,000 miles and the shifting is still a little "rough" at times, so I might have to modify my gearbox oil selection. I'll give it a little more time though before I make a change.

I was surprised to see that the workshop manual states 10-40. I’m also surprised it states semi synthetic.

This is an old school air cooled motor, with, relatively speaking, larger clearances.

Surely a thicker oil would be better for those clearances and surely fully synthetic would stand up to the heat (inevitable in an air cooled engine) better?

I’m pretty convinced that the 20-60 Redline I use in the old Cdo will also be better suited in the new ‘un too.

After it’s broken in of course!

bushman said:

Amsoil Metric Motorcycle 10-40 full synthetic - engine & transmission.

Tried 20-50 in the transmission & clutch and found the clutch grabby - when apart the plates were blotchy, so I don't think thicker is better at least for the clutch.

Click to expand...

No issues with the full synthetic in the tranny? I'm an Amsiol guy.

I have been running Shell Rotella 5W40 FULL SYNTHETIC JASO MA qualified in Engine and Trans/clutch since first oil change. I now have 6300 miles on it. And No complaints .

bushman said:

Amsoil Metric Motorcycle 10-40 full synthetic - engine & transmission.

Tried 20-50 in the transmission & clutch and found the clutch grabby - when apart the plates were blotchy, so I don't think thicker is better at least for the clutch.

Click to expand...

Was the oil that you tried one that had the necessary friction modifier additives for use in wet clutches?

Triumph recommends Castrol full synthetic 15W50. I'm an Amsiol fan but I like this oil and it's in my '17 Triumph. May be what goes in my 961 next.

Well, a 15-50 would seems more appropriate IMHO. Give it a go and let us know how it works out.

One of the things that might figure in the oil recommendations is that the 961 has a full roller crankshaft, where the Triumph and old Commando have plain bearings in the rods. Not sure what difference that would make, but it is a difference. I'm about to do the first oil change on mine, and also wondering which oil to choose. For sure a full synthetic.

Ken

Redline 20-60 motorcycle oil is my usual choice Ken, and I rather suspect that it will be my 961 choice as well.

I don’t have my manual with me at present, and am trying to understand the gearbox oil situation, and have a question: does the gearbox and primary drive share the same oil?

YES , Primary Drive and Transmission share oil supply .

Regarding roller bearings and oil applications that Icrken brought up. Twin cam Harleys have utilitied a roller bearing on the backside camshaft since 2001. The prior twin cams had ball bearings on the back cam that gradually disengaged. Switched to a roller cam bearing on the back side and problem over. My observation is that if you use a top shelf oil, if you have a failure it's probably the motor and not the oil. HD recommends 20W50 oil so viscosity in not the total picture.

TonyA said:

YES , Primary Drive and Transmission share oil supply .

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Thanks Tony. That’s a shame, and a tad unusual IMHO.
It would have been nice to put a specific gearbox oil in the gearbox and a friction modifier clutch friendly oil in the primary.
I guess a good modern motorcycle engine oil, with friction modifiers, designed to be shared throught eng, trans, clutch, is the way to go.
I prefer the idea of fully synthetic though personally.