Oil - semi or fully synthetic?

Goofle · 27-03-2019, 08:53 PM

I’m sure this has been done to death - sorry - but is fully synthetic worth it for a 93 M900? It’s coming to change time and I’m not sure. The price difference isn’t the issue - a few pounds - but I’m wondering if there’s any point on a engine which I’d imagine wouldn’t have been designed with fully synthetic in mind?
While I’m pushing my luck, any favoured brands?
I’m thinking 10/40 incidentally unless told otherwise.

Chriswilly · 28-03-2019, 01:12 PM

Tim Hyett recommended Castrol R 10/40 when he stripped my motor 18 months ago - not discoloured and used none since (low mileage - 12000)

Capo · 28-03-2019, 01:57 PM

I would not recommend R

28-03-2019, 02:11 PM

Quote:

Originally Posted by Goofle

I’d imagine wouldn’t have been designed with fully synthetic in mind?

This is a very old myth. No one ever designed an engine for an engine oil. They designed an engine and specified the best oil that was available at the time the bike was sold.
In many cars that have a few years production run with the same engine you will find that the later versions specify a newer oil spec.

jerry · 28-03-2019, 05:30 PM

On all my 2 valve motors I use a good semi synthetic and on 4v motors fully synthetic as they need it for the cams and they rev higher ,,, my preferred btands are putoline for 2v and Motul for 4 v motors

Goofle · 28-03-2019, 07:43 PM

I settled on Castrol fully synthetic - from Halfords. The Monstro will soon be back on the road again - now in Mid Wales!

Goofle · 28-03-2019, 07:44 PM

Ps can a moderator move my location to Powys please?

Nickj · 28-03-2019, 11:24 PM

Since pre WW1 Castrol R (CASTROL brand name BTW is derived from CASTER and OIL) has been a mixture of synthetic oil and castor oil, the castor oil has surprisingly good boundary layer lubrication properties (pistons, cam lobes). The castor oil component has always been low, just enough to give the anti-scuff properties which means way less than 1%.

These days it's a bit niche, awesome stuff if you happen to run a methanol fueled 2 stroke.

I suspect Tim said Castrol POWER1 Racing 4T 10W-40 which is a modern 10-40 synthetic oil and CASTOR only appears in the brand name!!

27-03-2019, 08:53 PM	#1
Goofle Registered User Join Date: Feb 2014 Location: Powys Bike: M900 Posts: 334	Oil - semi or fully synthetic? I’m sure this has been done to death - sorry - but is fully synthetic worth it for a 93 M900? It’s coming to change time and I’m not sure. The price difference isn’t the issue - a few pounds - but I’m wondering if there’s any point on a engine which I’d imagine wouldn’t have been designed with fully synthetic in mind? While I’m pushing my luck, any favoured brands? I’m thinking 10/40 incidentally unless told otherwise. Last edited by Goofle; 27-03-2019 at 08:56 PM..

28-03-2019, 05:30 PM	#5
jerry Old Git Join Date: May 2006 Location: Cricklade Bike: Multiple Monsters Posts: 2,814	On all my 2 valve motors I use a good semi synthetic and on 4v motors fully synthetic as they need it for the cams and they rev higher ,,, my preferred btands are putoline for 2v and Motul for 4 v motors __________________ MONSTERMAN

28-03-2019, 11:24 PM	#8
Nickj Too much time on my hands member Join Date: Jun 2007 Location: Forest Of Dean Bike: S2r Posts: 3,189	Since pre WW1 Castrol R (CASTROL brand name BTW is derived from CASTER and OIL) has been a mixture of synthetic oil and castor oil, the castor oil has surprisingly good boundary layer lubrication properties (pistons, cam lobes). The castor oil component has always been low, just enough to give the anti-scuff properties which means way less than 1%. These days it's a bit niche, awesome stuff if you happen to run a methanol fueled 2 stroke. I suspect Tim said Castrol POWER1 Racing 4T 10W-40 which is a modern 10-40 synthetic oil and CASTOR only appears in the brand name!! __________________ "The final measure of any rider's skill is the inverse ratio of his preferred Traveling Speed to the number of bad scars on his body." Song of the sausage creature

28-03-2019, 01:12 PM	#2
Chriswilly Registered User Join Date: Sep 2012 Location: gloucester Bike: M900ie Posts: 133	Tim Hyett recommended Castrol R 10/40 when he stripped my motor 18 months ago - not discoloured and used none since (low mileage - 12000)

28-03-2019, 01:57 PM	#3
Capo You Are What You Is Join Date: May 2005 Location: A Foward Location Bike: S4r Posts: 1,948	I would not recommend R

28-03-2019, 07:43 PM	#6
Goofle Registered User Join Date: Feb 2014 Location: Powys Bike: M900 Posts: 334	I settled on Castrol fully synthetic - from Halfords. The Monstro will soon be back on the road again - now in Mid Wales!

28-03-2019, 07:44 PM	#7
Goofle Registered User Join Date: Feb 2014 Location: Powys Bike: M900 Posts: 334	Ps can a moderator move my location to Powys please?