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What type oil should I be using for an 850 commando. The manual recomends 20w 50. Is sythetic better?
Be careful.....it lubes real well, but some is too thin and will pass through the seal into the primary case. I stopped using it...but others may give you other advise...wait and see what others write....I don't know everything.
I use Mobil 1 15/50 in my 750 Commando and have done for 2 yrs. It sumps more easily than 50 or 20/50 obviously but with a tight pump and reground bottom end (6000 miles now) it's not a problem. Warm-up gets the excess oil back to the tank in a couple of minutes. What I noticed after 3-4k miles is that the magnetic pickup doesn't have many filings on it. With the straight or multi oil there was always a nice little furry Xmas tree of iron/steel. That's not to say there isn't a bunch of bronze and aluminum whizzing around but if I rip open the filter after a 2000 mile change there's nothing in it. Check out www.realclassic.co.uk and look for the Gerry Bristow oil article. he's a Commando owner living in Crete (Hot place) and an ex oil co. employee. Seems to know what he's talking about. Yes it's expensive but engine wear is even more costly. Check out www.nortonclub.com and look in articles for oil and temperature testing. It's an eye opener. Hope this helps
I went down this road as most of us have..

I settled for Pentrite oils, after having several conversations with Les Emery at The Norvil Shop in UK.

He told me that they had developed the Penrite product in conjunction with Pentrite oils to work and suit the Norton engine, with their race engines.

Being a member also of classicbike.net, there was a very heated and protracted debate over oils some time back.

I am sure the goils and blokes here with Jerry, have all experienced the same debate.

I know blokes that swear by the synthetic product, in fact a good mate in Melbourne swears by the Mobil I product ..

I have generally always owned GT~ sports orientated vehicles including bikes and cars ~ and always used Castrol GTX.. I know blokes that still swear by GTX ~ GTX GTX~ even today!

I like the Penrite HPR product and am currently usng the HPR 40 which maybe be on the heavy side.. but I am comfortable with. (I simply ildle up and run the bike at a steady pace till I feel the l is completely warmed up ~ some 20 miles.. before I consider giving the bike any degreee of "stick".)
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