Forum

[Martin (Sale Mcr)]

When the clutch is separate from the gearbox oil, the choice of oil to use
to cool the clutch, is down to you to use what ever you prefer..........
But when the same oil must be used for the engine, gearbox and clutch, as use a common casing, what oil should you NOT use.

I was recently reading in a motorcycle hand book, from the mid ninety’s, that a API ref SF 10w/40, should be used. While understanding that SF has been superseded a few times, I was going to use SJ.........
However when trying to buy 10w/40 SJ, the only spec. that I find in the shops is SL and SM..........
These specs were new to me, so on checking them out on the net, I find that the SL data is unclear, BUT SM MUST NOT be used in any wet clutch application !!!!!! .............

So gents, please may I ask for your experience in such matters, as I have a bike with very clean but empty sump. .....
Sorry for bring up the subject oil once again.

REgards Martin

[Les H]

Hi Martin. Many unit construction bike engines with a common oil to lubricate the clutch specify a "JASO" spec oil. The specification limits the slippage of the clutch compared to using ordinary oils. I don't know what the recommendation is for Bullet UCE/EFi engine is. The latest API rated oils have less ZDP antiwear chemical that older API specs...whether that is detrimental to your engine I don't know either. You can of course buy high zdp oils with API ratings such as sf/sg still....see Millers oils....Morris Oils even castrol "classic" oils.

[Paul M H]

Hitchcock's use the following oil in there bikes for comparison so that would do fine.

COMP4 15W-50 In EFI

A more modern engine oil ideal for the new fuel injected EFI Bullets. It gives better protection for the wet clutches and is very effective from cold starting.

Note: Hitchcock's use 15W-50 in their EFI Engines
PART No. DESCRIPTION PRICE
SILK40 COMP 4, 15W-50, 1 LITRE, SILKOLENE £9.00
SILK41 COMP 4, 15W-50, 4 LITRE, SILKOLENE £34.50

[PeteF]

I would have thought that any motorcycle specific oil would do. I just use Halfords semi synth M/C oil in the Honda.

[grunda 12]

hi martin ,i use 20/50 from wilkinsons in engine and primary and gearbox(sealed bearings) on my 350 petrol bullet no problems ,change every 2000miles cost currently £9.00 for 5 litres atb paul.

[Leon Novello]

Just use a motorcycle oil, not a car oil; particularly not synthetic oil, they have friction modifiers, and are very slippery. From memory, Penrite sell motorcycle oil for wet clutches, stating on the label, No friction modifiers.

[seen some changes]

Just a word of warning, I know in this country it is unlikely to happen but on a recent run out across France I was chasing a friend on his Laverda averaging 60 mph in temperatures of around 24 to 28 C for about 80 miles or so when suddenly there was a woomph like noise and a large amount of smoke from the primary chaincase. We surmised that the standard engine oil being used had become hot enough to vapourise and then exploded, destroying the charge coils and magnet at the same time.The only oil we could get hold of was some fairly heavy grade auto transmission fluid which after repairing the charge system got me a further 1200 miles across France and back up to Yorkshire with no signs of clutch slip at all. In future I will be using this type in the primary chain cases of both my Constellations and the 500 big head I am rebuilding at the moment