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Dave

2024-06-11, 20:02:05
Have you tried the new Drafts feature yet? I just lost a long message today and learned my lesson. It is a good idea to save a draft of any long post you are writing. You can then just keep writing and keep saving a draft, knowing you have a backup if there is a glitch. The draft is automatically deleted when you post the message.

Dave

2024-06-08, 18:30:04
For Sale
xman has two very nice 1950's machines available - a green 1950 mk4 and black 1951 mk5 - both in good condition and running well.

Dave

2024-06-07, 02:13:36

Dave

2024-06-03, 08:23:05
For Sale
Duncan has just listed his green and cream 1957 Dragonfly for sale with spares and documents.

Dave

2024-06-02, 08:34:05
Parts avalable
alistair still has parts available - barrels, carburettor, castings - see all listings.


Dave

2024-06-01, 18:33:27

Dave

2024-05-28, 00:09:46
Welcome to the new site!
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1922 Douglas 4HP B22 Intake Manifold Question

Started by wheelhousegarage, 30 Nov 2022 at 17:01

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wheelhousegarage

Hello Douglas motorcycle community! My name is Bill Wheeler and I am brand new to this forum. My father and I own two Douglas motorcycles and enjoy learning about them.

In the attached photo, what are the threaded fittings on the intake manifold for? I found a photo of another B22 that has some hard lines coming off of them, but I wasn't able to figure out where the lines travel to. Is it a breather with optional air adjustment? Your assistance is much appreciated!

P.S. I also host a weekly show on YouTube called "A Bike and a Beer" where I feature rare vintage motorcycles every week and this bike will be featured this Saturday! Tune in and subscribe https://www.youtube.com/channel/UCnMcv6JVXjHwwMRuJSgmc9A if it meets your fancy  :D 

EW-Ron

Have you investigated where those fittings lead to inside. ?
Some form of (primitive) hot air feed into an internal heat exchanger perhaps  ??
With an option to switch off for warmer weather ...



Thought your name looked familiar.
Enjoy your work ...

P.S. Another pic shows its a bleed off the exhaust system - so pipes hot gas through there.
https://www.yesterdays.nl/site/wp-content/uploads/2017/04/Douglas-1922-4hp-w-6.jpg

wheelhousegarage

That was my best guess as well from studying that other bike - I appreciate your input! I'm pretty sure the holes just go straight into the intake manifold with an option to close the right side (front side).

Thanks for your kind words too!

EW-Ron

I'd think there should have been a tube inside, connecting those 2 connectors.
Unless there is a (sealed) connecting tunnel in the alloy casting itself. ?
So the hot exhaust gases could give some heating to the fuel/air mix.
Essential for cold weather running ?

wheelhousegarage

Here's my new video about this bike if anyone is interested.



Thanks again for your help!