1953 R51/3 Vin# 536383

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Restored - For Sale (Price on Request)

This 1953 R51/3 motorcycle, Vin # 536383 was manufactured on September 4, 1953 and delivered October 10, 1953 to the German dealer Brodersen in Tonning Germany. It came to me on November 10, 2019 from a friend who got the bike in pieces after 25 years apart and in in storage.

The R51/3 is probably the most beautiful and elegant design of all the post war BMW designs. The unique elements of the plunger frame, standard tank with its rear sloping form, and the “elephant ear” front fender, make the R51/3 stand out in the BMW lineup of bikes from that era.

Plunger frame BMW motorcycles are becoming rare and harder to find if you want one. I purchased this 1953 R51/3 project from an old friend. that I had purchased other projects from him in the past.

Inventory, dismantling, accessing and evaluation are the beginning steps. What is here, what is needed and what is usable. This process will take a few weeks before a restoration plan can be laid out. The sheet metal is in good condition except the tank is an early /3 Hoske 8 gal. and rough condition.

This motorcycle came to me in a semi-complete condition. The motor needed a new crankshaft. I purchased one from Kevin Brooks that he had rebuilt by Chris Chambers years before. The cylinders were pitted beyond use so I had them sleeved and brought back to standard bore and fitted with a pair of Schmidt pistons… But as usual with these types of projects, there are always more hidden issues to deal with that were unknown to both the seller and myself.

But understanding and working the intricacies on these old motorcycles have been made easier with the introduction of the Barrington Manual for /3 and plunger motorcycles from Barrington Motor Works in Barrington, NH. Christopher and Barbara Rowe Betjemann have done a superb job researching, compiling, and publishing their BMW restoration and service manuals.

The transmission was in very poor condition with not only damage to the case but some of the gears. A transmission was purchased from John Swift and sent to Benchmarkworks to be gone through, re shimmed and fitted with new bearings and seals.

The final drive unit also had serious pitting on the seal mating surfaces, no shims, pitted and missing bearing needles with damaged and frozen parts. The drive unit was also sent to Benchmarkworks and rebuilt with correct parts.

The carbs were totally rebuilt by me with new jets and seals and the bodies media blasted using a 9-mil glass bead that created a very nice surface similar to the original.  The bike came with a large Maier tank in very poor condition and a standard /3 tank was purchased from Greece, repainted and striped.

The front fork dampers and fork tubes were pitted and oxidized beyond repair. Everything had to be replaced along with all seals gaskets and rubber parts.

The original 6-volt charging system was installed with new points, condenser and coil. The original system produces very reliable service. I have used 12 volt systems from Benchmarkworks if the 6 volt system is damaged and not repairable.

This bike comes with a clear Michigan title in my name and the documentation from the BMW group archive stating its build date and original dealer it was sold to.

Detailed photographs of this restoration process and other restoration projects can be seen at www.airheadrestorations.com.

For more information on this bike, contact Jim using the form below:

    Modifications and/or Repairs:
    • Triple matching number motorcycle, engine, frame and head plate.
    • The frame was powder coated gloss black.
    • Tank, and fenders single stage painted in Avus Black and hand pinstriped
    • The bike came with full hubs and were mounted with aluminum high lip wheels and stainless steel spokes, also supplied.
    • The bike has new stainless-steel axels.
    • New wheel bearings were properly pre-loaded and lubricated.
    • New 350 x 19 Metzler tires and tubes mounted and balanced.
    • Original R51/3 cylinders were sleeved, bored, and new Schmidt pistons installed.
    • Original heads were fitted with new guides, seats, and BMW valves.
    • The final drive and driveshaft were rebuilt and shimmed by Benchmarkworks.
    • Transmission was replaced and rebuilt by Benchmarkworks with all new bearings and seals.
    • New front-end components were shimmed and sealed.
    • The original correct black face with domed glass speedometer was beyond reapir and replaced with new.
    • The carbs are correct, original, 1/22/61-62, cleaned, bodies media blasted with 9-mil glass beads, and fitted with new jets, needles, floats, and gaskets.
    • Correct new 30″ handle bars were added.
    • All chrome parts have been re-chromed.
    • All aluminum parts have been professionally polished.
    • New Pagusa solo seat was installed.
    • The magneto was rebuilt.
    • The wiring harness, switches, and cables are new.
    • It has a new /3 petcock and fuel line.
    • The /3 spark plug caps with BMW logo are correct.
    • A new set of exhaust headers and torpedo mufflers were mounted.
    • The sealed battery is in period correct battery box.
    • The original 6-volt Bosch horn was rebuilt and installed.

     

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