Author Topic: EW350 Restoration Questions  (Read 1445 times)

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Offline SteveTea

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EW350 Restoration Questions
« on: 21 Nov 2019 at 20:50 »
This is my first post here so a quick introduction to myself and the Douglas we have.

A couple of friends and myself have acquired a 1926 EW350 from a local man who we helped with clearing out his garage.  Most of the bike was discovered at the back of the garage with other major parts such as the gearbox and rear mudguard in a separate shed.  The bike was in a bit of a state and once we got all the parts together, we did a quick assembly to see what we had, picture attached.

All the main parts are present but, not surprisingly, there are a lot of problems that we are finding as we strip the machine down.  Two of us have some experience in working on old bikes but none of us have worked on a machine this old before, so expect a few posts here with questions and please excuse any that might be a bit daft, were on a steep learning curve!

So, here are some issues that we need help with and would appreciate some advice:

We have the flywheel of and have stripped down the clutch. Most of his is in fair condition but where the friction plate is riveted to the primary chain sprocket has come loose and the friction plate has been damaged by the stresses on the sprocket as shown in the attached photo.  The question is, has anyone got a friction plate / sprocket assembly they are willing to sell or is there a way to repair the existing assembly?

All of the valve guides need to be replaced but we are not aware of a supply for direct replacements.  Is there an alternative part that can be modified/machined to fit the Douglas?

One of the studs for the rear cylinder, the one between the two valves and also holds the mounting parts for the tappet cover, has been bodged in the past. The stud has been replaced with a bolt and some of the parts that hold the tappet cover are missing.  These are shown in another attached photo, with the missing parts arrowed.  If anyone can help with these parts that would be great.

Ill leave it at that for now, if you have any comments or advice to give, Id love to hear from you. Stay tuned for further instalments!

Offline douglas1947

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Re: EW350 Restoration Questions
« Reply #1 on: 22 Nov 2019 at 18:51 »
Steve,

I had repaired the clutch (of my 1930 H3 350cc, nearly same engine as EW) with glued on clutch lining (lining was made for me to special order).
So you have also no trouble with the worn rivet bores in the plate.

The cylinder bolt is possible available from LDMCC spares secretary, if you are member in the club.

Michael

Offline Doug

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Re: EW350 Restoration Questions
« Reply #2 on: 23 Nov 2019 at 00:22 »
Damage such as that to the clutch plate center is not uncommon. At lease someone has not applied the common repair of welding it to the sprocket sleeve! A proper repair is not easy, not unless you are skilled at a lot of miniature weld build up of the worn and torn tabs and dressing back to a accurate fit. It would be simpler to try and find another clutch disk. They did make a fair number of 350EW models (it was one of their more popular) and the same clutch center was used for quite a few years afterwards on the lightweight models.

There have been a few posts here on 350EW (or EW350) rebuilds, so a little searching and you ought to find plenty of info and pictures of what you will be encountering.

-Doug


[grammar change.  23Nov19 -Doug]

« Last Edit: 23 Nov 2019 at 15:56 by Doug »

Offline SteveTea

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Re: EW350 Restoration Questions
« Reply #3 on: 23 Nov 2019 at 15:26 »
Steve,

I had repaired the clutch (of my 1930 H3 350cc, nearly same engine as EW) with glued on clutch lining (lining was made for me to special order).
So you have also no trouble with the worn rivet bores in the plate.

The cylinder bolt is possible available from LDMCC spares secretary, if you are member in the club.

Michael

Hi Michael,
Thanks for the information but the rivets that are the cause of my problem are the ones that hold the metal plate to the central sprocket (which in turn fixes to the taper on the end of the crank shaft) its not the ones that hold the friction material to the plate.
One of the owners of this bike is a member of the LDMCC and he tried them for some parts including the cylinder bolt etc but they could not help.

Steve

Offline SteveTea

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Re: EW350 Restoration Questions
« Reply #4 on: 23 Nov 2019 at 15:32 »
Damage such as that to the clutch plate center is not uncommon. At lease someone has not applied the common repair of welding it to the sprocket sleeve! A proper repair is not easy, not unless you are skilled at a lot of miniature weld build up of the worn and torn tabs and dressing back to a accurate fit. It would be simpler to try and find another clutch disk. They did make a fair number of 350EW models (it was one of their more popular) and the same clutch center was used for quite a few years afterwards on the lightweight models.

There have been a few posts here on 350EW (or EW350) rebuilds, so a little searching and you ought to find plenty of info and pictures of what you will be experiencing.

-Doug

Thanks, Doug.
So, that leaves me to ask if anyone out there has a clutch plate for a 1926 EW 350 taking up space in a shed or garage that they would be willing to sell?

Offline douglas1947

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Re: EW350 Restoration Questions
« Reply #5 on: 24 Nov 2019 at 17:12 »
Steve,

sorry for my response to your clutch problems.
I have not noticed, that not the lining is your problem, but Doug had a good idea for a repair.

I have measured the missing cylinder stud on my engine:
it is dia 5/16" x 25 threads, I think it is a special Douglas thread.
May be you can get the tool (Tap + Die) from LDMCC, try also for the nuts.

Michael

Offline Aero

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Re: EW350 Restoration Questions
« Reply #6 on: 24 Nov 2019 at 20:15 »
Hi, your tappet guide clamp looks very similar to the one I made for my 36 Aero. It was fairly easy to fashion from a strip of steel, heated  to red heat where the bends were required & pips welded onto the end, followed by grinding to get the required shape. Regarding the rather unusual 5/16 x 25TPI thread I've found metric fine M8 x 1mm pitch is a fair substitute, as its very close to the diameter & has a 25.4 TPI count.

Offline SteveTea

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Re: EW350 Restoration Questions
« Reply #7 on: 30 Nov 2019 at 12:44 »
Hi, your tappet guide clamp looks very similar to the one I made for my 36 Aero. It was fairly easy to fashion from a strip of steel, heated  to red heat where the bends were required & pips welded onto the end, followed by grinding to get the required shape. Regarding the rather unusual 5/16 x 25TPI thread I've found metric fine M8 x 1mm pitch is a fair substitute, as its very close to the diameter & has a 25.4 TPI count.
Hi Aero, thats good information, thanks very much.
Steve

Offline Doug

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Re: EW350 Restoration Questions
« Reply #8 on: 30 Nov 2019 at 14:37 »
Initially the 350EW had screw in tappet guides. These had holes in the face for a peg spanner. Then in 1927(?), they adopted the design from the 600EW of a tapered socket and bridge clamp. The clamp remained the same for the subsequent 250/350cc models until WW2.



Larger image HERE

PDF version HERE

-Doug
« Last Edit: 30 Nov 2019 at 17:33 by Doug »

Offline SteveTea

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Re: EW350 Restoration Questions
« Reply #9 on: 06 Dec 2019 at 14:19 »
Initially the 350EW had screw in tappet guides. These had holes in the face for a peg spanner. Then in 1927(?), they adopted the design from the 600EW of a tapered socket and bridge clamp. The clamp remained the same for the subsequent 250/350cc models until WW2.



Larger image HERE

PDF version HERE

-Doug
Thats interesting as mine is a 1926 and has the screw in tappet guides but it also had one bridge clamp as well.  I assumed the clamp was a good idea as it would stop the tappet gude unscrewing with the engine vibration which is something that did happen on one of the tappet guides without the clamp.  The loose tappet guide vibrating around in its threaded hole in the crankcase resulted in some wear of the alluminium thread in the crank case.  I will attempt to make a new clamp based on your drawings.  Many thanks for the information.

Regards, Steve

Offline lovejoy

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