What grade of oil

[Jeff Swann]

Just took delivery of my 1912 model H 2 3/4hp Douglas read through all the paperwork, owners manual, etc., but no mention of what grade of oil I should use, I have 30's & 40's Classic oil ??

Also could I use multi grade in my dragonfly??

[eddie]

Jeff,
        I run my 1913 2¾hp on straight 40 grade oil with no problems, and the Dragonfly on 20/50 multigrade - again with no problems. Having said that - I would not put a modern multigrade oil in a Dragonfly engine that had run on monograde without a crank strip down to remove any accumulated sludge. It's amazing how much sludge gets trapped in the crankpins - and the detergents in multigrade can easily get it on the move - with the possibility of blocking the crankpin oil holes.

  Regards,
                 Eddie.

[Jeff Swann]

Cheers once again Eddie for your prompt reply, hopefully meet you one day soon. Jeff

[BrmBrm]

Engine oil for Dragonfly.
I note Eddie's warning re. multigrade, detergent, and blockage of oilways.
I'm going to use a 20w/50 as an oil for very light use,  to evaluate the rest of the bike before a full engine strip down. I'm assuming that the clutch is a dry clutch, if so I could presumably use a car oil rather than a motorcycle oil.