I'm interested in your timing gears if they fit a 1921 350cc. Thanks 

Quote from: Black Sheep on 10 Nov 2025 at 07:23 I do have timing gears if necessary.
Gordon.

I'm interested in them if they fit a 1921 350cc. Thanks 

The one I have is an old Bruce Main-Smith photocopy. It shows it fitted t the 1910 model C, but not the cheaper model B.

-Doug

Awesome thanks I found also video from 6 years and could just make out. Be interesting to see the cataloged, is there a pdf? 

Looked through the half dozen pictures of early 1909-11 models that I took or copied and none had the chain guard. I questioned that it even belonged, but see that they did have that abbreviated guard depicted in the 1910 catalog. Unfortunately the illustrations are too small to show any detail. Then I remembered there were a pair of 1910 models at the 2003 Bristol Cavalcade event. One of which had the chain guard and I snapped a photo of it. It is mounted on top of the bracket. If that is correct or not, I do not know.





-Doug

Hi see picture, looking at 1910 chain guard from photos I can see shape design. The question is have does the guard sit onto of the frame bracket or under. I am hoping someone can post picture.

Hi all,
I was repairing one of my old garden sheds and found under the rubbish three Dragonfly heads, a left and right plus another they are rusty, one or two broken fins, the threads look okay so full restoration required.

Free to anyone who must be willing to collect from Swansea (10 miles from M4) as I don't want the hassle of posting them, if I don't get any takers by 7/1/26 the scrap man can have them, if anyone requires more photos PM me your email address and I will forward them

Seasons greetings to all

Colin

You do not want to use a bronze material for valve guides in a 'dry' application; inlet or exhaust. They are better suited for enclosed valve gear where there is a positive lubrication, like an oil mist. Douglas (and many others) use cast iron as it does have some inherent lubricity in between the infrequent applications of the oil can.

Some of the later racing models tapped oil vapor off the crankcase which coalesced in small oil lines that ran to the individual valve guides. They were drilled through the head/guides as you describe. I am not aware that the RAs would have this feature, but it could have been added later. Usually when encountered they are choked shut with carbonized oil.

-Doug

I've removed the valve guides from the two cylinder heads. The inlet ones are bronze and the exhaust ones cast iron. Both the exhaust ones have been broken. All four guides are stopped from rotating by pegs located in the heads that locate with cut-aways in the guide shoulder. I assume this is to maintain the alignment of small (2mm) lubrication holes in the guides and matching holes in the head. However, these holes have no evidence of external oil feed fittings and are just 'free to air'. 

I had planned to make four new valve guides from phosphor bronze, but a friend has queried whether the exhaust guides will be adequate in bronze rather than cast iron. Any advice from those better qualified than I in metallurgy would be welcomed.

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