Hey Gents, all is running as of tonight, just a fuel leak as I think the corks have had it even though they have been in a jar of fuel, but all good so far, she fired up on second kick, so thanking Mick for the bolt, so should make the memorial service on Sunday once Ive got the head down properly.

I'm running some pretty 'gucci' oil in my M20, Its the vintage Morris stuff that costs a fortune, now I havnt changed the oil for roughly a year and hardly used the bike in that time, only a few hundred miles at most, the stuff looks as though Ive just put it in, Im also running with a rather high spec oil filter I got from the US, its reuseable for ever, designed for Race engines and is the dogs wotsits, so what are the thoughts on oil change intervals, I know oil has a life span..

I'd change the oil if I were you, the oil itself hasn't done too much work, but the contaminants from combustion from when you have used it form acids that can actually etch components like crank pins, it happens more when the air gets to the oil coated components and as yours is a dry sump (If it hasn't wet sumped!!)is the ideal situation for this to happen, combine this with condensation absorbed from the atmosphere will hasten any etching.
While we are on the subject, it is a good idea to change the oil before laying a bike up for the winter rather than changing it when you pull it out again in the springtime to prevent the above. It also helps if the engine was allowed to wet sump or was deliberately filled with oil as there is less room for the air to condense. It dosen't matter too much if the bike is used all year as it is the combination of condensation from being stood with the components such as the big end rollers and the contaminants that cause the etching

email (option): davmax@ntlworld.com

Hi Kit,

Mineral oil should be changed every 6 months and synthetic every year
due to oxidation of the oil and degrading in its specs, regardless of if used or not.

It actually has an expiration date on the box also, even if sealed and unused.

Noam.

email (option): noam10@gmail.com

Hi Kit...Mine is run on a regular basis most of the time..Under 'normal use' I change the oil every 2000 miles.(BSAs recommended interval).Economising on oil is a false economy..it's cheaper than engine components and easier to 'fit'...Ian

email (option): ian@wright52.plus.com

cheers, oil change it is. I didnt know that Dave..