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  1962 R50S
restoration photos
 
 

Installation of the transmission output shaft and new bearings. Notice the rear cover studs which were removed and CAD plated.

The heads were rebuilt by none other than Randy Long. He installed new valve guides in aluminum bronze, new exhaust valve seats that are more temperature and abrasion resistant, new intake and exhaust valves in stainless (Black Diamond or similar), new titanium spring keepers and retainers along with new single coil springs. He ground the seats to the proper location and width per BMW specs. He then vacuum tested the heads for leakage. The exhaust valves are R50/60 type with 7mm stems rather than 8mm that R50S used.  R50S valves with 8mm stems aren't available in stainless and repops are over $100 each. The valves Randy used are less than $40 ea.  Also valve guides with 8mm bores would have to be machined from 7mm guides. 

Here's the motor case post cleaning with the replated and reinstalled cylinder and transmission studs.

Here's a process that is usually necessary on most old BMW's, machining the carburetor flanges. Over the years, some owners find the need to tighten the carb mounting nuts with herculean force. The soft pot metal flanges easily bend inwards over time which can prevent proper sealing on the gasket. The remedy is to machine the carb flanges back to a flat surface which allow the carb to seal properly.

Here's a shot of the original steering damper linkage and Boge hydraulic unit post restoration. Most folks choose to replace this version with later friction damper unit. Quite simply, the friction style offers better performance (it actually works!) and is easier for the restorer due to the lack of available parts for the hydraulic version. Going for pure originality versus function, I choose to restore the original system. There are four rubber washers and three bushings which are not reproduced. The rubber washers can be adapted from R26/27 parts and the bushings can be turned on a lathe. I choose Delrin for the linkage bushings and a pliable skateboard truck bushing for the shock eyelet bushing. The plating is Teflon based for smooth operation and provides a very original appearance.

The front brake backing plate is ready for installation. The shoes were relined and all visible parts were replated.

The R50S speedometer is model specific and this version with trip odometer is certainly the rarest of the post 1955 era.

The R50S air tubes are model specific as well. Believe it or not, I found these and the speedometer on Ebay about 6 years ago!

The Klaxon horn was restored to working order. The fasteners were replated and my painter tried to match the sheen and lesser quality finish.

Horn's are pretty easy to restore as long as you keep track of the parts. I like to lay out the each part as it's disassembled and place them in a row from front to back. I take a photo to refer back to when reassembling.

I was fortunate to find these NOS mufflers which are shared between the R50S/69S only.

It's always a treat to open, or in this case, unwrap NOS parts. You never know what you are going to find. There could be dings, rust or scratches. Luckily, the former owner took good care of these mufflers which could have been easily dented over the years.

The R50S uses a header unlike any other model. A cast aluminum finned nut was installed after chrome and the end was flared to capture the nut. For restoration, the only way to remove the nuts is to cut the header tubes. My headers were dented beyond repair but the finned nuts were perfect. Since there are no chrome R50S headers available (stainless repros are available from Craig Vechorik), I had to get creative with a pair of Mobile Traditions R50 headers. In this photo, the headers were protected with electrical tape and cut on a band saw 1.5" from the crossover outlet stub. The cut will end up centered and hidden behind the header hanger strap (see following 3 photos).

Here's the header after the cut. Notice the groove on the inside of this brand new (rusty) Mobile traditions header. The groove will act as a key to help sleeve the two tubes back together after the finned nut is installed.

An aluminum sleeve was turned and slotted to match the groove on the inside of the header pipe. The sleeve presses approximately 1.5" into each tube. This slot and groove act as a key to position the header exactly as it was prior to cutting. Also notice the black cross-over tube which matches the badly rusted original. All reproduction systems use chrome or stainless. To mimic the original, a hi-temp ceramic powder coat was applied.

Here's the trial fit of the two header pieces sleeved together. For the final installation, I used Hi-Temp RTV to join the pieces and create a tight seal. With the hanger strap installed, the seam is totally invisible. It would have been much easier to purchase stainless reproduction headers from Craig Vechorik. However, stainless turns gold with heat and would have been a poor match for the NOS bright chrome mufflers. Also, I wanted to use the original finned nuts as opposed to reproductions. Refer back to the R50S page to see the final results.

I purchased these NOS axles from Craig Vechorik. The part number decals would seem to indicate later production period but these are the real deal. BMW axles were hard chromed with blackened threads.