As I am new to the British Motorcycle scene (recently purchased a 1956 Model 18S) I am not up to speed with the do's and don'ts yet.
Can anyone tell me if it is OK to use modern day Castrol GTX 15/50 in the engine. I was recommended this by a local motorcycle dealer as he had no staight 50.
Model 18S Engine Oil
-
Mark Bruce.
- Posts: 5
- Joined: Wed Oct 12, 2005 10:45 pm
- Location: UK
-
silverarrow
- Posts: 549
- Joined: Mon Jan 01, 1990 12:00 am
- Location: LEICESTERSHIRE UK
Model 18S Engine Oil
Mark,
On my 18S i always use a straight 50 oil. i'm not an oil expert but have asked the same question as you in the past.
The 50 oil does not thin out in use as a multigrade does which means thinner oil, lower oil pressure, more wear.
I would use a multigrade if it meant getting a bike on the road or to top up in an emergency.
You should be able to get 50 grade oil from most bike shops, major shows or auto jumbles. There are several manufacturers Rock, Morris's etc as well as Castrol. If you prefer Castrol you can ring 01954 231668 who are the distributors & who can supply direct or advise as to your nearest distributor.
I also use straight 30 oil in the chaincase as a multigrade or 50 oil tends to cause clutch drag.
Hope this helps.
Les Smith
On my 18S i always use a straight 50 oil. i'm not an oil expert but have asked the same question as you in the past.
The 50 oil does not thin out in use as a multigrade does which means thinner oil, lower oil pressure, more wear.
I would use a multigrade if it meant getting a bike on the road or to top up in an emergency.
You should be able to get 50 grade oil from most bike shops, major shows or auto jumbles. There are several manufacturers Rock, Morris's etc as well as Castrol. If you prefer Castrol you can ring 01954 231668 who are the distributors & who can supply direct or advise as to your nearest distributor.
I also use straight 30 oil in the chaincase as a multigrade or 50 oil tends to cause clutch drag.
Hope this helps.
Les Smith
Keep smiling
-
Rohan B.
- Posts: 136
- Joined: Wed Oct 12, 2005 10:45 pm
- Location: AUSTRALIA
Model 18S Engine Oil
I don't know about Castrol 15/50, but the old 20w/50 GTX was not recommended for roller bearing motors, despite what the oil companies may say about their then "modern" 20/50.
There was a very famous demonstration of this in Australia some years back. A Ducati (roller bearing motor) in a race here used 20/50 multigrade, not the factory recommended straight 50, and had big end failure after just 4 hours of (racing) use. Ducati Factory said multigrade oil was not adequate for roller bearing motors, end of story. Duc was winning until went bang, so folks noticed....
I'd be wary of 15/50, unless they can demonstrate high mileage motors with normal useage pattern..
hth,
Rohan.
There was a very famous demonstration of this in Australia some years back. A Ducati (roller bearing motor) in a race here used 20/50 multigrade, not the factory recommended straight 50, and had big end failure after just 4 hours of (racing) use. Ducati Factory said multigrade oil was not adequate for roller bearing motors, end of story. Duc was winning until went bang, so folks noticed....
I'd be wary of 15/50, unless they can demonstrate high mileage motors with normal useage pattern..
hth,
Rohan.
-
Mark Bruce.
- Posts: 5
- Joined: Wed Oct 12, 2005 10:45 pm
- Location: UK
Model 18S Engine Oil
Many thanks to all those who gave advice. I am going to the show at Glamis Castle next month so I should pick up straight 50 there.
-
silverarrow
- Posts: 549
- Joined: Mon Jan 01, 1990 12:00 am
- Location: LEICESTERSHIRE UK
Model 18S Engine Oil
Chriatian,
Why not send a copy of the article to the Jampot editor so that the highlights could be published for all members to see.
I think the summary of the comments from all scribes on this subject & what i am told from Casrol Classic Oils is Play Safe - use Straight 50 Oil!
Les Smith
Why not send a copy of the article to the Jampot editor so that the highlights could be published for all members to see.
I think the summary of the comments from all scribes on this subject & what i am told from Casrol Classic Oils is Play Safe - use Straight 50 Oil!
Les Smith
Keep smiling
-
Kieran Enright.
- Posts: 16
- Joined: Wed Oct 12, 2005 10:45 pm
- Location: UK
Model 18S Engine Oil
Another point to be wary of with multigrade oils is that, like with most things, there are polymers (viscosity index improvers) and polymers, and they're not all the same! Some are pretty tough, and others much more fragile. It's pretty much a case of, you get what you pay for.
As well as being chewed up in roller bearings, and piston shear in long-stroke engines, they are broken down by micro-organisms which live in moisture dissolved in engine oil. When they break down, they form gummy varnishes which are brilliant at clogging up narrow oilways, and sticking piston rings in their grooves. This point is specially worth considering if you only do a low annual mileage, and/or if you ride pretty gently. In fairness, multigrades were not designed for these sorts of engines, but for short-stroke engines with plain bearings. Horses for courses!
Best regards,
Kes Enright
As well as being chewed up in roller bearings, and piston shear in long-stroke engines, they are broken down by micro-organisms which live in moisture dissolved in engine oil. When they break down, they form gummy varnishes which are brilliant at clogging up narrow oilways, and sticking piston rings in their grooves. This point is specially worth considering if you only do a low annual mileage, and/or if you ride pretty gently. In fairness, multigrades were not designed for these sorts of engines, but for short-stroke engines with plain bearings. Horses for courses!
Best regards,
Kes Enright