Author Topic: 500cc Dragonfly barrels and pistons  (Read 2943 times)

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Offline P10

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500cc Dragonfly barrels and pistons
« on: 07 Nov 2012 at 19:23 »
Pair of new linered aluminium cylinder barrels for 500cc Dragonfly conversion complete with a pair of new boxed pistons, rings, gudgeon pins, circlips and compression plates. 500.

« Last Edit: 21 Nov 2012 at 17:55 by Dave »

Offline Ray Dodds

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Re: 500cc Dragonfly barrels and pistons
« Reply #1 on: 09 Nov 2012 at 15:46 »
Helo do you know if they will fit Mk engines, Regards Ray.

Offline P10

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Re: 500cc Dragonfly barrels and pistons
« Reply #2 on: 09 Nov 2012 at 16:01 »
Sorry Ray but I am not an expert on Douglas engines.  I have a Dragonfly and only know their condition and that they were made for that model.

Offline eddie

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Re: 500cc Dragonfly barrels and pistons
« Reply #3 on: 09 Nov 2012 at 16:59 »
Ray,
        The Dragonfly barrels are much shorter than the Mark barrels and have a different stud configuration on the base. Also, these barrels can only be fitted to the Dragonfly after the crankcase mouths have been bored out to accomodate the larger liners.

  Regards,
                Eddie.

Offline jimbo

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Re: 500cc Dragonfly barrels and pistons
« Reply #4 on: 12 Jul 2013 at 19:53 »
Hi Ray,

    Are the alloy barrels still for sale? I would be interested....

                                                                                   Jim

Offline Paul Taliesin

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Re: 500cc Dragonfly barrels and pistons
« Reply #5 on: 13 Oct 2017 at 11:12 »
Does anybody know who made these 500 alloy barrels? Anybody in the club?
Would be very interested to get my hands on a pair? How did they work out on the bike more torque and performance?

Offline eddie

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Re: 500cc Dragonfly barrels and pistons
« Reply #6 on: 13 Oct 2017 at 17:05 »
Paul,
        I think these barrels were cast from the pattern for the barrels on the black and silver Dragonfly special that we spoke of in a previous posting. There were some extras made, but they were sold off at a Douglas Club rally several years ago. The biggest problem is finding suitable pistons to use with them - flat twin pistons have the valve cutaways in line with the gudgeon pin instead of at 90 degrees to it.

  Regards,
               Eddie.