Author Topic: Douglas 7260/4 ready to go  (Read 2895 times)

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Offline twirl

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Douglas 7260/4 ready to go
« on: 08 Jan 2016 at 09:44 »
Over the past two years I have restored a Douglas MK4. The machine is not entirely in its original state. The front fender is from the MK3. Apparently it was replaced decades ago, because the original gained a reputation to rotate with the wheel after a certain time. I got the motorbike with M-handlebar, DKW headlights and Tomaselli fittings. Obviously, one of the former owners showed sporty ambitions. Other than those provided in the series, even the rare sports camshafts were installed. As a tribute to this past, the Tomaselli fittings have remained and a small and straightened handlebar was mounted. Because the sport camshaft suffered from pitting, I got some normal camshafts from the Douglas Club Spare Departement.. Notwithstanding the series now a 7 inch headlamp is fitted (Original 6 1/2), so I can use with H4 35/35 watts instead of the Lucas-BIFOCUS. Last, I changed the passenger seat, which is normally fixed and feathered directly on the fender. Now it is mounted on a small luggage carrier. For my tours, I usually ride with saddlebags. For this reason, the original painted toolbars  remained blank, the saddlebags are a little scrubby.
There were lotís of rust, of course, but no holes. I had to bulge a lot, too. The frame is now powder-coated, the fenders very nice wet painted by a professional refinisher. Tank and small parts I have painted myself with 2K spray cans. The surface is gas resistant and the 2K paint is hard to be polished with a rotating disk. Therefore inclusions can be polished away. Frankly, I would not have thought that such good results are possible with spray cans. Technically the rusty "Radiadraulic" fork made a lot of effort, steering head bearing and the torsion bar spring on the other hand needed only new grease. The engine needed a total overhaul. The crankshaft was fixed by alpha bearings. As John Mark in his manual suggested, the machined oil groove now is blocked. The original way to give more oil to the timing gears will obviously cause a disastrous lack of oil for the crankshaft. Many other good advice came from London Douglas Motorcycle Club respectively the Douglas forum. Bing carburetors from the old Heinkel scooters are now responsebal for mixture preparation. The conditions in the cylinder and in the combustion seemed to be very similar me. As you know, itís impossible to get original Amal carburettors. I'm curious to see how successful they will work.
I enjoyed restoring this bike, because of its high constructive quality claim. Itís true, in the of the post-war period due to cramp finances this claims sometimes got lost in production. But in my point of view, Mr. Douglas deserves respect. Great thanks deserve to Richard Bradley form the Douglas Club Spare Departement. Because I hat do restore the bike in a small garage, I had to go step by step not to overload my small workbench. I am afraid, my step-by-step-ordering caused a lot of work to him. Thank you very much, Dick!
« Last Edit: 08 Jan 2016 at 10:45 by twirl »

Offline twirl

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Re: Douglas 7260/4 ready to go
« Reply #1 on: 08 Jan 2016 at 09:55 »
Former days.

Offline duggy the douglas

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Re: Douglas 7260/4 ready to go
« Reply #2 on: 06 Jun 2016 at 08:50 »
Hi nice bike, I have a mk 4 and have issues with the carbs I see you used bing carbs . Are they ok and have you a part number I could have.
many thanks
Adrian

Offline twirl

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Re: Douglas 7260/4 ready to go
« Reply #3 on: 05 Sep 2016 at 15:37 »
Hi Adrian, I am sorry you had to wait for my answer such a Long time. The carbs I used are Bing 1/20/5.  The bing carb works with an acceleration pump and was fitted to Heinkel-Scooters. Especially the acceleration therefore is great. They work well, but the idle jet could be smaller, as I will try soon.
First I had some trouble with the throttles, because this carb needs a stronger throttle spring. I fixed the problem by an additionally spring inside the throttlecable-distributor. Some other carbs that seem to work well are the Dellorto carb PHBG 18 AS 2507 in connection with the MCM04 Dellorto manifold. There is an article in the New Conrod Sept/Oct 2016.
« Last Edit: 05 Sep 2016 at 15:44 by twirl »