oh no an oil question

brian cornford · Post by **brian cornford** » Wed Apr 05, 2006 7:00 am

After 2 days of internet searching (including this site's excellent oil question strand) and book reading I still need Help!

Problem is a 900 S2 E/S.

This bike had Mobil 1 synthetic in when I bought it - clutch tended to slip.
I changed to straight 40 but the battery could hardly turn the lump over (British weather /temperature conditions).

Battery changed for a new one to suit a BMW- most oomph I could get in the space. No improvement. Next, EXPENSIVE gel battery. It's better but...... .

Now I know why it originally had Mobil 1 in it.........presumably far less friction on start up.

Anyway, handbook recommends 10W50 (mineral oil, presumably) but finding this is a nightmare!

So, what does anyone recommend for a cool climate that will protect at full running temperature, contains few friction modifiers so the wet clutch does not slip, is not high in detergent so less frothing, has good rwsistance to shear, and is runny enough to get round the engine quickly when cold in a cool climate, and allow several goes at starting if necessary before the battery dies!

Will semi-synthetic do the job?

What do all you Darmah and S2 owners use in a cool climate?

All ideas welcomed! Thanks for your help.

Brian Cornford

Colin Linz · Post by **Colin Linz** » Wed Apr 05, 2006 3:49 pm

I can’t offer any personal experience; it just doesn’t get cold where I live. But from the other oil thread and some engine oil manufacturers use lists 20w50 would suit and is fairly common. It also appears that synthetics are OK, and these might be a better option when using multi grade oils.

I noticed recently that Briggs and Stratton now allow synthetic multi grade oils to be used instead of a mono grade mineral oil, they still say no to multi grade mineral oils though. Air cooled engines can run at higher temperatures than liquid cooled engines and in general have severer operational environments. These high temperatures can break down the Viscosity Improvers used in multi grade oils. If I were to move to a multi grade oil I would be looking at synthetic types, but I would also be checking out claims of roller bearing failures too.

bitzz · Post by **bitzz** » Fri Apr 07, 2006 8:23 pm

You just missed the oil threads to end all oil threads in the Bevelheads.

Anyway, use any of the latest syth 10-40 or 10-50 and you're good to go.

Peter Mille · Post by **Peter Mille** » Sun Apr 30, 2006 2:17 am

Castrol RS 4T (Racing Synthec) 10W50 full synthetic for my '85 Mille!!!
www.castrol.com
I just noticed that Castrol UK don't sell this viscosity in England, but they do sell Castrol R4 Superbike 5W40 full synthetic, and they still sell the superior Castrol Formula RS 10W60 ( I used that for years!) look at the "Classic" section.