Sound of open mufflers on a BMW R51/3

Just can’t get enough of the sound of open mufflers

Repair part for R51/3 – R68 half hub wheels

We now offer a top quality wheel hub repair part (PN 36312030026.7) for the R51/3 to R68 half hub wheels – splines have a perfect slide fit with the original BMW driving dog (PN 33120026232) – the HRC value of the repair part is between 30 to 34, measured at the splines. An original wheel hub measured 29 HRC – the repair part has the appropriate alternating recesses for the spokes, both on the front and back side of the flange:    the recess for the spoke head is deeper and has a concave shape, whereas the recess for the spoke bend
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Dimmer switch R25, R51/2

There are 2 versions available in the market. The one on the right has a lower push button housing. The hole in the housing does not align with the hole in the connector, as a result the wire cannot be connected properly.

BING jets

BING jets are stamped with numbers, such as 35, 40 (idle jets) and 110, 115, 120 etc (main jets). One would expect that these numbers refer to the diameter of the jet bore, however this is not the case. This is confimed by the company BING in Germany. A few examples of main jets measured with a wire / jet gauge: BING 44-051 main jet 130 = gauge 120 (= 1.2 mm) main jet 125 = gauge 110 (= 1.1 mm) main jet 120 = gauge 105 (= 1.05 mm) main jet 110 = gauge 95 (=0.95 mm)            
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Matra 282 tool

We mill 2 planes on the threaded bushing so that it is possible to use a 22 mm wrench on the threaded bushing. This is necessary in cases where (for instance) the crankshaft bearing is glued to the bearing journal, to prevent the threaded bushing from rotating while tightening the central bolt

Cylinder heads R50 – R69S: butterheads and LK heads

Very informatieve article by Duane Ausherman on “butterheads” and LK heads: http://www.w6rec.com/duane/bmw/head/

Brake levers with finger grooves

The brake levers with finger grooves (PN32722072252) currently available in the market, do not fit in the throttle housing of the R26, R27, R50 – R69S models. The hole for the lever screw is of few thenth of a millimeter off it’s original position: the lever gets blocked and cannot be “opened”. New brake levers that do not have this problem are only expected to become available by the end of 2017. Till then, the solution is to mill off +- 0.3 mm from the edges on both sides. After polishing, no traces of milling are visible anymore. This is what
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Exhaust pipes

Different exhaust pipes are available in the market, unfortunately not always an exact replica of the original pipes: the shape of the bends does not correspond with the original BMW exhaust pipes as can be seen on this picture. The 2 lower exhaust pipes are identical to the original pipes    some of these pipes follow a slightly different path than the original exhaust pipes. This causes a problem for the R67 – R67/3 models: in the horizontal section, they’re not running close enough to the frame, causing too little clearance between the brake pedal and the right-hand exhaust pipe, as
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R50S & R69S emblems

Different qualities emblems are found in the market. See this example of the R50S emblem. In our opinion, the upper one is the better quality, both in shape and in finishing.   The differences are easily recognized: for example the shape of the “5” and “S”   The upper emblem follows the contour of the rear fender, the lower one is too flat. The back side of the lower emblem doesn’t have the smooth finish of the upper one. Please note that these emblems are very fragile! During installation, make sure that the holes in the rear fender are exactly
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Carburetor overhaul

With hardly any new carburetors being produced by BING for the < 1969 BMW mono and twin motorcycles, it’s getting increasingly important to be able to repair and overhaul the used original carburetors. Luckily, special parts and tools are available nowadays to restore the carburetors to a good working condition. A. Idle mix screw: very often, the M7 x 0.75 mm screw thread in the carburetor housing is worn out. There are 2 good solutions to this problem. 1. drill the threaded hole to 7.9 mm – cut M8 x 0.75 mm screw thread – install the idle mix screw with
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Driving dog R51/2 – R68

Part nr: 33120026232 Next to the original BMW driving dog, an after-market version is available in the market. At first view, the after-market product gives the impression of high quality machining. However, there are at least 2 flaws: 1. the geometry of the splines:the splines of the after-market part almost have a V shape instead of the trapezium shape on the original part. This V-shape is normally seen on worn splines 2. The diameter of the needle bearing seat measures 39.94 mm whereas the original parts measures 39.97 mm. This will result in too much play on the needle bearing The
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