what oil grade and type is the best and most common used in 850 electric start commandos
Ran my 850 Mk 3 on 20/50 multigrade for 20 years in Kenya when it already had 21,000 miles on the clock and on standard bore when I bought it from the police. Now back in UK with some 35,000 odd miles on the engine still use 20/50 and it's still on standard bore following professional rebuild 2,000 miles ago. Change engine oil and filter every 1,500 miles.
... Halfords Classic 20/50 mineral , to complete my reply.
Hi Robert, there are as many answers to this question as there are oil producers. It's a matter of personal preference, and you will be advised on everything from old mono grades through to fully synthetic oils.
I would respectfully suggest going back through the forum or looking through old roadholder mags. Good luck.
I run my 71 fastback on Silkolene Super 4 20-50 semi synthetic. Ran my original commando in the 70's on Castrol GTX 20-50. With no problems. I also raced Yahama engined sidecars in the 90's on Super 4, never had any problems with lubrication. A better quality oil should mean fewer problems. I wouldn't go to fully synthetic as it's very thin and would probably make the engine noisy, and would probably wet sump even easier.
We all have our preferences and oil formulations have changed over the years. Back in the early 1970s I found that the 20W50 GTX of the day had protected the engine of my Triumph 650 well when I dismantled it after 40,000+ miles of hard use. Oil changed regularly every 1500 miles.
For today's oils there is an extensive test documented over on Access Norton https://www.accessnorton.com/Oil-Tests/NortonOil.php.
The tests can be criticised for relevance and repeatability but a couple of 'reference point' oils tested well, i.e. Castrol R40 and Mobil 1 V-Twin 20W50 synthetic (recommended by the late Gerry Bristow, NOC member ex-Duckhams).
Of the 'classic' 20W50 oils readily available in the UK Castrol XL tested well.
That's what I'm using based on the test results.
Morris monograde SAE 40 on my Mk 3. Better oil consumption than with standard 20/50 multi grade.
Out of respect for the electric start, first start of the day is using kickstart. Any subsequent start on a cold engine I turn the engine over firstly with the kickstart to ‘break the seal the seal as it were.
Change the oil every 1500 miles circumstances permitting.
Nb it’s also what Norman White uses.