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Dave

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How much oil

Started by Sgtbiro, 14 Mar 2019 at 20:40

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Sgtbiro

Hi all i am about to replace the oil in my Dragonfly shocks so can anyone please tell me how much oil to put into them, i presume that because they are different lengths there will be a different amounts of oil in the front to the back, and what is the best type of oil to use.

Cheers Kevin..

Sgtbiro

Was this just a silly question or does nobody really know the answer ?

eddie

Hi Kevin,
              Some years ago, I refilled the front dampers on my Dragonfly, but like you, I didn't have any idea of volume or grade of oil to use. Just by trial and error, I used 10 grade fork oil, but overfilled the units on the first attempt. The 10 grade oil gives about the same damping rate as was available with new mid 50's units (remember, the damping in those old units was never as good as modern units - and in my opinion, gave a better ride!). The only suggestion I can make as to volume of oil is to part fill the damper body - insert the damper unit and pump it to eject all the air - then top up the oil until it again half fills the body - then screw on the top and pump the damper to make sure there is no more trapped air in the actual damper, but there needs to be some air in the outer reservoir to provide a cushion and prevent a hydraulic lock as the unit is compressed. Don't expect to get super damping - those old Girlings were ideally suited to the Dragonfly and gave a super smooth ride - I once heard it described as being 'like low level flying!'

  Regards,
                 Eddie.

P.S.  I used 10 grade fork oil, but any equivalent grade of hydraulic oil should be OK - don't try to get improved damping by using an engine oil as that may 'froth up' in use, giving progressively worsening damping.

Sgtbiro

Cheers Eddie.
Thank you for the advice i will certainly give that a go, just trying to keep my Dragonfly as original as possible so i did not want to put new shocks on before i try to salvage the old ones.

Regards Kevin..

tck

One of the ways I have kept my oil filled Vincent dampers to better than original performance is to insert bubble wrap in the cylinder that way the  unavoidable air cannot enter the system and the unit can be filled up

Sgtbiro

Quote from: tck on 23 Mar 2019 at 15:44
One of the ways I have kept my oil filled Vincent dampers to better than original performance is to insert bubble wrap in the cylinder that way the  unavoidable air cannot enter the system and the unit can be filled up
Cheers i will give that a go and see how i get on.