Recent Posts

Pages: « 1 2 3 4 5 6 7 8 9 10 »

what price do you have in mind?
Don't need it but might be wise to have a set in stock...
Have a set of barrel - but no bike for these.
They are in excellent condition.
Nothing broken, except one Champion spark plug.
No pistons and barrel is undemaged inside.
Front and rear one.

Please send me a message by PM if you are interested on.

Thanks Bernd
Identifying Douglas Motorcycles / Re: Barrel identification
« Last post by BernardsE31 on 15 Mar 2019 at 09:25  »
Thanks for pictures.
My barrels looks exactly the same - 36...38 Aero I learned.

Front barrel has an union for oil?
Rear barrel not.

Identifying Douglas Motorcycles / Re: Barrel identification
« Last post by Doug on 15 Mar 2019 at 06:26  »
Views of a 600cc Aero (and cylinders).

Douglas Motorcycles - General Discussion / Re: What Type of Douglas is this?
« Last post by Doug on 15 Mar 2019 at 06:20  »
Here are some pictures of the Thorpe twin-cam cylinder heads. I believe these were the same as used on the later iterations of the Thorpe single-cam.

The have the same angled downward ports (the cylinder on the left is inverted) as the Works 1932 machines had. Unfinished casting on the right. Note the fins around the ports are filled in. These were finished by roughing out with a hacksaw and finishing with a file. For a bit of manual labor it greatly simplified the pattern work; a very pragmatic approach.

Here can be seen the JAP inspired rocker gear. Except for the cover plate, it might well be JAP components.

And a view propped in place.

The cylinder barrel. Alloy with iron liner. The distinctive fin shape is a reconcilable feature.

An period photo of the Thorpe single cam outfit in an earlier guise. Here it still has the Douglas valve gear (rocker arms and oil reservoirs recognisable), exposed pushrods, and no sump. The sump and side mounted oil pump looks very much like the style used by the Works on their 1930-33 racing models.

1956 Dragonfly. The bike is 99% complete and requires re-assembling. The wheels need either new rims and spokes or re-chroming or powder coating. The engine has been re-built, distributor, crank have been re-conditioned and valves re-seated. needs valve collets,oil filler plug, oil filter cover and the rockers are off a different model but can be obtained. Has plate but is dead, can be traced back to its original owner. Not matching numbers. Can be viewed on
Douglas Motorcycles - General Discussion / Re: Amac carb
« Last post by Hutch on 15 Mar 2019 at 02:29  »
Welcome to the forum Leon! Nice looking Douglas 2 3/4 HP you have.

I have also not found a lot of info. on these circa 1914 AMAC carbies, but some information can be found in the Douglas 2 3/4 HP instruction booklets and in the AMAC Hints and Tips brochures. A copy of these can be found here;

(note:- this is the 1925 version which contains information on the later carburettors used on the 2 3/4HP)

I have attached the AMAC carby pages out of the 1914 Working instructions of the 2 3/4 HP Douglas Motor Cycle. Reproduction copies of this can be obtained from the LDMCC

These carburettors are essentially the standard AMAC carburettor of the day with a heat jacket added to help prevent carburettor icing in certain atmospheric conditions. If your circumstances required this feature, you would need to add a small diameter (copper) pipe from the blanked off fitting on the rear cylinder exhaust pipe of the to the rear hole on the underside of the heat jacket on the carby. These would have had a small clamp on them to clamp the pipe into the fitting. There is then another "mini" exhaust pipe going from the front hole downwards to exhaust the hot gas towards the road. As a lot of 2 3/4 HP's with AMAC heat jacketed carbies have not got the heat jackets connected up it probably is not essential for correct running in most cases?

Your carburettor also has an "aftermarket" adjustable jet needle added to the main jet. This may complicate the tuning procedure until you are familiar with its adjustment - I guess in days gone by people felt the need to fiddle with the adjustment - just like today I suspect!!    :) .


Douglas Motorcycle Technical Articles / Re: Manual Oil Pump
« Last post by Bert on 14 Mar 2019 at 23:16  »
Iíve just had to rebuild the oil pump on my 1913 2 3/4 hp. I found that the one way valve and spring at the base of the pump is missing, however the valve on the top of the crankcase is in place.  My engine has apparently been running for quite a few years in this guise.
I tried to unscrew the Ďlidí but reckon Iíll break the slotted thread if I try any harder. Given that both one way valves work in the same direction between pump and engine, are two necessary?
Douglas Motorcycles - General Discussion / How much oil
« Last post by Sgtbiro on 14 Mar 2019 at 21:40  »
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..
Identifying Douglas Motorcycles / Re: Barrel identification
« Last post by Eric S on 14 Mar 2019 at 20:18  »
Not checking dimensions but they looks exactly like the cylinders on my Aero?
Pages: « 1 2 3 4 5 6 7 8 9 10 »