Author Topic: Many questions from new Douglas owner  (Read 738 times)

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Offline cycarmark

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Many questions from new Douglas owner
« on: 19 Aug 2018 at 22:07 »
I've got a 1929 B29 and have already found out about the lack of tires available for the bike (many thanks for all the helpful replies).  I got the engine running briefly and it sounded good, however before I run it longer I had some questions:

The exposed valve stems and springs, do these require any type of lubrication?  The ones on my bike look fairly dry.

Any suggestions for lubrication for the primary chain?

It has Champion 7 COM-L spark plugs on it, any more modern equivalent or has anyone used the adapters to allow use of a 14mm plug?

A cosmetic question, should the alloy brake plates be painted or left aluminum color?  I've seen them both ways on photos on the internet (even one with a black one in front and aluminum in rear). 

Thanks all!

Offline graeme

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Re: Many questions from new Douglas owner
« Reply #1 on: 20 Aug 2018 at 07:27 »
For the valve stems, squirt them with a chain lube that has a good amount of graphite in it with the engine running before heading off on a ride. This should be reapplied every 100 miles or so. For the primary chain use a sticky chain lube. I would suggest running NGK A7 spark plugs. I think the brakes plates should be bare aluminium, that is what I am familiar with for Douglas machines of that vintage

Cheers, Graeme

Offline cycarmark

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Re: Many questions from new Douglas owner
« Reply #2 on: 20 Aug 2018 at 11:14 »
Thanks Graeme, much appreciated!

Offline Doug

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Re: Many questions from new Douglas owner
« Reply #3 on: 20 Aug 2018 at 15:57 »

Offline cycarmark

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Re: Many questions from new Douglas owner
« Reply #4 on: 20 Aug 2018 at 16:19 »
Excellent Doug, hard to find those "offside" pictures.  Thanks much.

Offline ian scott

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Re: Many questions from new Douglas owner
« Reply #5 on: 21 Aug 2018 at 09:59 »
Make sure that chain lube for the valves is chain oil not a chain wax or chain grease. I used a spray chain wax on my valves once and it glued them open after they got hot. Spray chain oil has worked very well for me though.

Offline cycarmark

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Re: Many questions from new Douglas owner
« Reply #6 on: 21 Aug 2018 at 13:27 »
I'll be sure to be careful what I use.  This raises another question, I noticed the valve stem and the tappet do not line up.  Is this a normal setup for the Douglas?

Offline Bert

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Re: Many questions from new Douglas owner
« Reply #7 on: 21 Aug 2018 at 16:30 »
That is fairly standard on many bikes. It makes the tappet slowly rotate as the valve is pressed by it therefore preventing excessive wear in the one spot. Even in a normal OHV head, the tappet is set just off centre to spread the wear.

Offline cycarmark

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Re: Many questions from new Douglas owner
« Reply #8 on: 21 Aug 2018 at 17:18 »
That makes sense, it is more pronounced on the Douglas engine than any other I've seen. 

Offline douglas1947

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Re: Many questions from new Douglas owner
« Reply #9 on: 21 Aug 2018 at 17:50 »
Hi Cycarmark,

Im just working on an 1930 350cc H3, the "follow model" of your B29.
My bike is original unrestored and the brake plates are black painted aluminium (you can also recognize this on Dougs specification picture).

Michael

Offline cycarmark

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Re: Many questions from new Douglas owner
« Reply #10 on: 22 Aug 2018 at 00:25 »
Thanks Michael, good to hear I'm not alone in getting one of these back on the road.  Keep me posted on your progress!

Offline Doug

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Re: Many questions from new Douglas owner
« Reply #11 on: 22 Aug 2018 at 07:39 »
The offset between the tappet and the valve stem is a design to allow the valves to be further outboard than the tappets. It keeps the timing chest narrow. In the case of the Douglas the offset does not impart a rotation to the valves. Usually that is facilitated by having a round tappet foot offset to the cam lobe. That causes the tappet to rotate slightly, and imparts some of that rotation to the valve. The Douglas tappet is prevented from rotating. If the valves do rotate, it is probably more due to accident than design; via the head of the lash adjuster flexing, causing an angular strike on the valve tip, that might induce some twist.

Valve rotation might have been known in the industry at the time (I am not sure without doing research) to reduce or even out wear, but I don't think Douglas knew about it! Or if they did, the layout of the valve train (inherited from the EW model) precluded it.

-Doug

Offline cycarmark

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Re: Many questions from new Douglas owner
« Reply #12 on: 23 Aug 2018 at 12:23 »
I had to go home and look at it, but I think I see what you are talking about.

Offline Ian

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Re: Many questions from new Douglas owner
« Reply #13 on: 27 Aug 2018 at 00:51 »
Re the brake backing plates - I have two with these brakes - one painted and one natural alloy. From the catalogue picture Doug put up looks as though yours should be painted.

With the sidevalve Douglases I find there is little need to lubricate the valves as enough oil gets through to them !! I just use engine oil for the bikes I have that do require it