Author Topic: Douglas Mark/Dragonfly Engine Oil should try Multigrade ?  (Read 219 times)

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Offline Paul Taliesin

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Hi All

Just wondering what oil people are using in their Douglas?
Are most people using straight Grade or maybe moved over to Multigrade oil?
I see inside my Dragonfly crankcases oil residue which seems to resemble Blackjack Grease. A good modern multigrade must be better for the crank and engine life? Obviously I will be using a nice cleaned out crank on mine in the future.

Offline eddie

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Re: Douglas Mark/Dragonfly Engine Oil should try Multigrade ?
« Reply #1 on: 09 Oct 2017 at 14:28 »
The purists still use monograde oil in the belief that in engines with roller bearings, the polymers in multigrade oil tend to stack up in front of the rollers. On the other hand, I have been using multigrade since I rebuilt my Dragonfly engine, and the crank has done just over 35,000 miles and is as good as the day I first fitted it. Provided it doesn't cause any problems, any oil that is readily available from the majority of gas stations, is the sensible way to go.
 If you are going to get your crank cleaned out, drill and tap holes in the crankpin plugs so that they can be drawn out - do not push them on through - that will force the accumulated sludge up into the bigend bearings and cause even more problems - then fit new plugs.

  Eddie.

Offline Paul Taliesin

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Re: Douglas Mark/Dragonfly Engine Oil should try Multigrade ?
« Reply #2 on: 10 Oct 2017 at 09:25 »
Sound advice I'll make sure there's no sludge left in the crank or any part of the engine.
I agree the multigrade is a much better option and will lead to longer life with engine with the added friction improvers etc
Do you use 20/50 or 10/40 oils mineral or semi synthetic?

Also what about the filtration I understand the dragonfly oil filter is no longer available?

Offline eddie

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Re: Douglas Mark/Dragonfly Engine Oil should try Multigrade ?
« Reply #3 on: 10 Oct 2017 at 10:18 »
I'm using 20/50 mineral oil. I'm still using an original oil filter but I believe some owners have managed to modify a BMW filter to fit (from a 650 twin, I believe).

  Eddie.

Offline Pensioner73

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Re: Douglas Mark/Dragonfly Engine Oil should try Multigrade ?
« Reply #4 on: 19 Oct 2017 at 08:41 »
I would have thought if you are not stressing the engine by racing or something, multigrade or monograde, oil is oil.
However, a friend of mine, who races vintage bikes, recommended I use the Douglas specified monograde with 10%-15% chainsaw oil because it is 'sticky' and coats the friction surfaces.
I tried it and my Dragonfly runs noticeably a bit quieter.