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Reference => Identifying Douglas Motorcycles => Topic started by: BernardsE31 on 14 Mar 2019 at 12:59

Title: Barrel identification
Post by: BernardsE31 on 14 Mar 2019 at 12:59
Hi,
have a pair of barrels and believe the should suitable for a 30s models.
Bore is quit large with around 75mm.
Location of ports are oposite aand not as for S6/T6 models.
Its not Mastiff as well.

Any idea?
Title: Re: Barrel identification
Post by: Doug on 14 Mar 2019 at 15:01
The shape is as for the 1936-38 500/600cc Aero models. However those were not offered as a 750cc to the best of my knowledge. Just 60 and 68mm bores (68mm stroke).

-Doug

Correction, Aero models & stroke: 68 x 68 and 74 x 68.
Title: Re: Barrel identification
Post by: eddie on 14 Mar 2019 at 16:22
They could be 'Aero' as the spec sheet for the DC/38 model lists the bore size as 74mm.

  Regards,
                Eddie.
Title: Re: Barrel identification
Post by: Doug on 14 Mar 2019 at 16:35
Oops, my mistake. I was looking at the bore figures for the earlier 82mm stroke engines. The 500 and 600cc Aeros were 68 x 68 and 74 x 68 respectively. Previous post updated.

-Doug
Title: Re: Barrel identification
Post by: BernardsE31 on 14 Mar 2019 at 17:05
Thanks for quick comments.
It make sense for a late Aero 600 with shorter stroke and big bore.
Heads looks also quit "modern" - they dont have the cooling plugs.

Thanks Bernd
Title: Re: Barrel identification
Post by: Eric S on 14 Mar 2019 at 20:18
Not checking dimensions but they looks exactly like the cylinders on my Aero?
Title: Re: Barrel identification
Post by: Doug on 15 Mar 2019 at 06:26
Views of a 600cc Aero (and cylinders).

(https://www.douglasmotorcycles.net/aa-files/images/doug/2019/Aero-cylinder/Aero-600-1.jpg)

(https://www.douglasmotorcycles.net/aa-files/images/doug/2019/Aero-cylinder/Aero-600-2.jpg)


-Doug
Title: Re: Barrel identification
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.

Bernd
Title: Re: Barrel identification
Post by: Doug on 15 Mar 2019 at 13:49
Bernd,

The union is to vent oil mist from the front tappet chest over (via a aluminum tube) to the primary chain case. You can just see this tube in the photo previously where it emerges from behind the oil lines and intake manifold.

-Doug