Just wondering can I use 4 stroke lawn mower oil in my M20 engine? It's SAE30 mineral monograde oil designed for air cooled SV and OHV engines. It is available in every petrol station and also relatively cheap.

email (option): kalle.tikas@gmail.com

I wouldn't, it's a bit thin. 5ltrs 40w or 50w Rockoil is about £15 so cheap enough and made for the stresses of a classic bike engine not lawn mowers.

email (option): horror@blueyonder.co.uk

Hi Ian,

Is SAE50 oil good for the engine? (“50X”)
We have this oil from local manufacture and a very high quality,
But is sold as strictly gear oil for use in gears which requires non-hypoid oils,
And with consistency as the SAE90.

I guess it is not the same as 50W?
I used to use mineral MONO SF 40 OIL
and last time used mineral MONO SF 20W/50.

What do you conceder best for the WM20?

Thanks,
Noam.

email (option): noam10@gmail.com

Oil always creates huge debates.....

When we run the vintage and veteran bikes, we use aircraft SAE50 oil and use aviation fuel which is still leaded and doesn't degrade - unlike the crappy LRP and lead-free stuff available at the pumps....... which has the shelf life of milk......

I have to say that this is an expensive option and down here in DDA, aviation fuel isn't exactly available over the counter. Need to have a pal with an aircraft!

email (option): brucekirby@telkomsa.net

Yes we've had this discussion a few times
You can use 40 or 50 in the engine, depending on how hot your country is or how you ride the bike. I think most people using this forum will say use 40 in the engine. I use 50 in my OHV Norton single as it gets very hot with a good thrash I doubt there is much difference between the 2 grades for normal use.

Oh it looks like the price has gone up, I'm sure it's about £15 at my local bike shop.

http://www.shop4biker.co.uk/product/Rock-Oil-Classic-50-Motorcycle-Engine-Oil-SAE-50-5-Litres.html

email (option): horror@blueyonder.co.uk