Oil and Filter 1982 DOHC

[BSA750four]

I have a cb750 I am told K2 engine in my side car outfit - number RC01E-2308884. you can see the engine in my profile picture.
Where is the best place to source an engine oil filter? I was told by the previous owner, he used, mineral 20/50 engine oil. Unfortunately he passed away. I cannot reconfirm with him.
I will try to source the oil. If I need to change to semi synthetic, anyone have experience of flushing the engine and which type of oil to use please?

 

[SenseAmidMadness]

"Flushing the engine" when changing from mineral to semi synthetic is absolute overkill. As long as both types meet the JASO-MA standard they will intermix perfectly and swapping over should not harm anything. Just drain out the old oil while the engine is warm and fill with the new.

The only real risk you run when changing away from mineral oil is that the synthetic or semi-synthetic might "cause an oil leak" with its better detergent content. Buildup from long-term mineral oil use can get cleaned away by the newer oil and can reveal leak points in oil seals and gaskets.

You're in the UK so a great source for any parts is David Silver Spares at https://www.davidsilverspares.co.uk/

 

[BSA750four]

Thank you. I know of David SIlver. I am in UK.
The engine has only covered 3000 miles. It was bought new/old stock in 2012.
The oil in the engine has just started to discolour now.
Should I continue wqith mineral oil. Is there a need to swap to semi synthetic. I have read mineral is better for cooling older engines?

 

[BSA750four]

I have found the answers to my questions.
Stay with mineral oil 20W / 50. Appears better for older engines.
The Vin number RC01E-2302452 means it is an negine of 1982 CB750KC
I have found the oil filters on David Silver and the oil elsewhere.
Thank you for your help.