Author Topic: 2 3/4 exhaust valve cap question  (Read 3213 times)

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Offline gsx1100s

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2 3/4 exhaust valve cap question
« on: 23 Jun 2010 at 06:04 »
Hello , I hope this finds you all well.
I have a question concerning the 2 3/4 engine. I have a 1918 motor. Instead of a normal  exhaust valve cap  , I have a similar bolt .with what appears to be a conical finning on top , it is about 1.5 inches long and has nine discs on it. These discs are slightly smaller than the previous disc under it , thus the conical shape. On the base of the bolt are printed the words " To fit Douglas M.G.C."
Many thanks in advance ,
Michael
« Last Edit: 23 Jun 2010 at 22:56 by gsx1100s »
"My first car was a motorcycle"

Offline Doug

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Re: 2 3/4 exhaust valve cap question
« Reply #1 on: 23 Jun 2010 at 23:40 »
Michael,

Fir cone caps. Aftermarket accessory that was supposed to help the engine run cooler by providing more radiating surface. I have never seen then on a Douglas, but certainly have seen them fitted to other makes of the teens and twenties.

-Doug

Offline gsx1100s

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Re: 2 3/4 exhaust valve cap question
« Reply #2 on: 24 Jun 2010 at 08:27 »
As always , thank you for sharing your knowledge

cheers michael

P.S. after receiving your information I found a picture of them on a JAP motor at this address :

http://www.cybermotorcycle.com/gallery/classics_s/Stylson_1929_250cc_JAP.htm
"My first car was a motorcycle"

Offline Frank Lyn

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Re: 2 3/4 exhaust valve cap question
« Reply #3 on: 25 Jun 2010 at 03:42 »
A set were on a 1919 2-3/4 that I owned very briefly,   
What caught my eye was that the front one was shortened to clear the front mudguard. 
The bike never ran while in my possession so I cannot comment upon their effectiveness



« Last Edit: 26 Jun 2010 at 10:31 by Dave »

 

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