Author Topic: Bowden carbs on Douglas 90 +  (Read 5939 times)

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Offline douglas1947

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Bowden carbs on Douglas 90 +
« on: 05 Apr 2015 at 12:00 »
My Douglas 90+ has fitted Bowden carbs.
I know they where not fitted originally.
Has anyone experience with that carburettors and what is the reason to change from Amal 276?

Michael

Offline 90plus

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Re: Bowden carbs on Douglas 90 +
« Reply #1 on: 05 Apr 2015 at 18:07 »
Can't help you with this one

I would suggest fitting the real thing .

Try : www.stayupfloats.co.uk

They seem to have a correct 276 Amal , handed pair for sale ........no info on condition.

Good luck,

Mfg,

Bert
the Netherlands
1951 90plus
1954 Mark V

Offline giz.neal

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Re: Bowden carbs on Douglas 90 +
« Reply #2 on: 09 Apr 2015 at 11:42 »
Michael,

Admittedly an expensive solution but, UK company Burlen Fuel Systems manufacture replica Amal 276 Carbs all set up to original specification for the 90+. They have a very good web site!

Giz

Offline Neville Heath

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Re: Bowden carbs on Douglas 90 +
« Reply #3 on: 12 Apr 2015 at 19:17 »
 This may be of interest. It depends on how you intend to use your 90, but I have used for thousands of miles  Japanese Keihin ones bought at jumble sales that have come off Honda 175's. They are marked 22mm choke but the bore dia of the stub is exactly right at 15/16". I have kept in all the original parts which are 100 main jet, 38 pilot, 113 slide, and needle 2nd grove from the top. You need to make a flange adaptor. No messy petroly fingers or gloves from tickeling. Push down the choke levers and away you go.
Neville Heath     

Offline David Lawrence

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Re: Bowden carbs on Douglas 90 +
« Reply #4 on: 12 Apr 2015 at 22:03 »
Micheal,
The Bowden carbs fitted to your 90 plus could well be original, although not common they were available from Douglas as a variation, several layouts were tried even right angle induction stubs with horizontal carbs have been documented, for some reason my computer refuses to allow me to open your jpg or download it so have not seen the photo of the type you have fitted.
If they work well I would save yourself a lot of money and keep a rather unique 90 set up!
Dave

Offline eddie

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Re: Bowden carbs on Douglas 90 +
« Reply #5 on: 13 Apr 2015 at 07:08 »
Hi,
     Looking at the shape of the 'bellmouth' on the Bowden carb, I wouldn't think it did much for the high speed performance of the engine! (especially as it also has a butterfly throttle). I read somewhere that Amal moved the needle to the side on the GP carbs because, with it in the centre of the airflow, the wave effect of the air hitting it, almost halved the effective bore of the carburettor!!

  Eddie.

Offline douglas1947

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Re: Bowden carbs on Douglas 90 +
« Reply #6 on: 13 Apr 2015 at 10:43 »
I have an original photo of my 90+ (a very early one: Frame No. 7652 / 90), when the bike was nearly new. It shows the bike with 276 Amals. Also high level exaust and studded tyres.
I have tried to attach the scanned photo, but it did not work.
I donīt know exactly what use the owner of the bike made, but it looks like something like crossing the country or sixdays.
There was no use of extra high top speed, so GP carbs made no sense.

I would like to know, if other owners have experience with the Bowden carbs.
And I would like to know, what is the reason to change Amals 276 to Bowden. Iīm shure, the 276 where not worn at that time!

Michael

Offline tck

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Re: Bowden carbs on Douglas 90 +
« Reply #7 on: 15 Apr 2015 at 17:13 »
I am certain bowden carbs were an alternative option I have a set that were fitted to the Douglas in my avatar (left)  I like the tip about the honda carbs I am sick to death of the Amals they may have been OK when we had petrol but  now we have the witches Ethanol brew they gum up chokes stick and are messy.

Offline Neville Heath

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Re: Bowden carbs on Douglas 90 +
« Reply #8 on: 16 Apr 2015 at 19:36 »
Dave
Not only were horizonlal carbs documented I have a pair. I have tried to send a photo but it has failed twice.
Neville







[Photos added. 03May15, Doug, Site Moderator]
« Last Edit: 03 May 2015 at 13:10 by Doug »

Offline Doug

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Re: Bowden carbs on Douglas 90 +
« Reply #9 on: 16 Apr 2015 at 22:49 »
Neville,

Email me the photo(s) and I will add it to the post.

-Doug
(Glen Mills, PA, USA)

Offline Doug

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Re: Bowden carbs on Douglas 90 +
« Reply #10 on: 03 May 2015 at 13:07 »
Photos added to above post.  -Doug

Offline douglas1947

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Re: Bowden carbs on Douglas 90 +
« Reply #11 on: 28 May 2015 at 19:14 »
Neville + Doug,

thanks for sending these intresting carb version!

Michael