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Douglas Motorcycles - General Discussion / Re: 2-stroke oil for a 2 3/4 hp?
« Last post by Hamwic on 12 Sep 2022 at 09:54  »
Apropos of two stroke oil - Riders of veterans and other bikes with exposed valve gear like to use a drop of two stroke oil added to the petrol. This is to lubricate the inlet valve stem(s), which gets no other form of lubrication. When side valve springs are enclosed, a puff of oily smoke from the exhaust guide is sucked up the inlet guide, but when the valve springs and guides are exposed, the dry inlet guide gets no oil, and with wear acts as an air leak, so a bit of oil here via the incoming fuel charge is good. My M32 has felt hats between the valve spring and the stem, and the application of the oil can is called for now and then to keep things sweet. Whether or not these are original or not I don't know, but it was a common modification to try to keep grit out, and oil the valve stems at the same time.

Cheers for now
Doug
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Douglas Motorcycles - General Discussion / Re: 2-stroke oil for a 2 3/4 hp?
« Last post by cardan on 12 Sep 2022 at 09:26  »
I did it for a while.

Two stroke oil seems like a good idea for a vintage four-stroke total-loss engine, where a decent amount of oil ends up passing the rings and being burned. Two stroke oils are "low ash" so should stop build up of crud in the combustion chamber. And I'm sure they would do a good job of lubricating bushes and bearings.

However the big downside is that the oils are usually rather thin and very "slippery". While using two-stroke oil (Valvoline Racing Two Stroke was the brew of choice) I had leaks everywhere, mostly around the hand pump and drip feed. Oil everywhere.

My choice would be straight low-additive mineral oil. I use on of the Penrite products: I think Shelsey Heavy (or whichever is a straight 50). If you're in cold climate the 50 gets very stiff, and a 40 or even 30 would be OK.

If you're just doing some local pottering on a 2 3/4, I'm sure the engine would tolerate any modern engine oil, despite what might be said out there. Better any oil in the oil, than some fancy oil in the tank but forgetting to put it in the motor while you're riding.

Leon
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Douglas Motorcycles - General Discussion / Re: S.L. Bailey
« Last post by Hutch on 12 Sep 2022 at 02:47  »
There are a few oddities with Douglas registration numbers. At the time, Kingswood was outside the Bristol boundary, so machines registered by the factory usually had Gloucestershire registrations, but for some obscure reason, Douglas registered some machines at their Bristol showrooms, so they received the Bristol letters - 'DD' ........
  Regards,
                Eddie.

Eddie and Leon,

I think you are onto something with the Gloucestershire vs Bristol registration numbers Eddie. This info. apples to cars but may also apply to motorcycles? Towards the end of this document ;

http://www.cvpg.co.uk/REG.pdf

there is a list of two letter registration codes and "AD" is Gloucestershire and "AE" is Bristol. We do see "AE" a few times on registration plates of some of the early machines shown on this forum. So Leon could well be on the money with "AD - D10". Is "D" the trade part of the plate i.e. D for Douglas and plate number 10?. I'm sure there is some expert out there laughing at me and the explanation is simple ! :-).

(EDIT:- One thing I didn't notice before - Alcock's machine is registered AE 4145 and Thornhill's 1914 TT machine (shown in Leon's reply #15) is AE 4144 .......only one number apart, so they may have a lot in common.....)

cheers

Hutch
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I read where one person said he was using quality 2-stroke oil for his 2-3/4.

Good idea ? Bad idea?

Seems to make sense but I don't want to risk my precious engine.

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Douglas Motorcycles - General Discussion / Re: S.L. Bailey
« Last post by Hutch on 11 Sep 2022 at 23:28  »

......A mystery however is the 4-valve-per-cylinder OHV motor that appeared at Brooklands in 1919. The cylinders were one-piece and were said to be aluminium. ......

The frame in which this motor appear is a precursor to the S1 (or a development from the 1914 3 1/2/4 hp model), with splayed down tubes but a single tube cradling for the motor. So far as I can see, all pre-war racers used the single-down-tube frame.

Leon

I was recently searching for Douglas motorcycle pictures in the Motorsports Image Website;
 
https://www.motorsportimages.com/photos/?race_type_id=&search=douglas+motorcycle

 and found that there was a picture that I had missed last time I looked, of what appears to be the same bike (and maybe the original of the same picture? EDIT:- you can see the leg of the person in the background so i think it is the same picture) that appears in The Motor Cycle (from September 4th 1919) article that Leon posted way back near the start of this thread and also mentions in reply #39.

This picture is very clear and shows great detail. One thing I noticed was the rear brake lever setup - one that is quite different to the production model version of the day. It seems to match the setup on A.E Wills 1920 Junior TT machine? There appears to be only one oil pump on the tank in this machine tho'. I don't know if this machine morphed into the A.E. Wills bike or it is a different machine?

Unfortunately the picture does not quite show us the valves as I would like to see how they might have configured the 4 valves per cylinder :-)

Cheers

Hutch

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Thank you!
77
I have some used EW valves and a oil pump and timing chest cover,
If you want I will sort out a few pics.

Regards Alan
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Douglas Motorcycles - General Discussion / Re: S.L. Bailey
« Last post by Hutch on 11 Sep 2022 at 08:56  »
Eddie,

Yes you could be correct and as you say it is just a coincident. I gather Douglas road tested the machines they manufactured on the road. I doubt they would have registered every one individually just to do that and would have had trade plates of some description? All of the 3 machines we have seen so far with "A-D-D" seem to have some association with the Douglas Experimental Department - so maybe that was the prefix to their "trade plate"? Don't know and Just a guess on my part....:-)

I had  a look through my collection of pictures and have not found any more with "A-D-D-...." plates on them. Could also be that it was something that Douglas did for publicity pictures and had nothing to do with actual road legal registrations (?) so your initial suggestion may well be correct - A Douglas Development number 10, but we do have yet another Douglas mystery to A-D-D to the collection! :-)

Cheers

Hutch
79
Douglas Motorcycles - General Discussion / Re: S.L. Bailey
« Last post by eddie on 11 Sep 2022 at 08:24  »
There are a few oddities with Douglas registration numbers. At the time, Kingswood was outside the Bristol boundary, so machines registered by the factory usually had Gloucestershire registrations, but for some obscure reason, Douglas registered some machines at their Bristol showrooms, so they recieved the Bristol letters - 'DD' (My 6 days bike is KDD466). When that OHV 2 was produced, the registration plates would have had just the 2 letters - so maybe you are right in that it could be an early trade plate, but it just struck me that ADD 10 was a very appropriate number - even if it was by pure co-incidence!

  Regards,
                Eddie.
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Douglas Motorcycles - General Discussion / Re: S.L. Bailey
« Last post by Hutch on 11 Sep 2022 at 08:12  »
Eddie and Leon,

:-) great replies ! The couple of similar plates I had seen before were the miniature Douglas 2 3/4 plate that Leon mentions, and I have attached the other one - Looks like it is A-D-D-5. From the Stilltime Collection and appears to be a spring frame prototype but without the  rear spring frame ? !! You can see the pivot point for the rear swing arm and where the springs may connect to the frame tube under the rear of the tank....but its rigid in the rear!!.

cheers

Hutch
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