Menu

There is a difference between “aftermarket” mufflers and “performance” mufflers. Aftermarket mufflers are designed in accordance with BMW specifications for mufflers produced after the introduction of new German legislation in the 1950s. Performance mufflers are designed according to pre-1953 specifications. Example: P/N 18124090003 Muffler “Fish tail” – RH – after market P/N 18124090003RDH Muffler “Fish tail” – RH – for optimal performance Background: Between 1951 and 1953, West Germany introduced more uniform vehicle regulations These were incorporated into the Straßenverkehrs-Zulassungs-Ordnung (StVZO) Around 1953, stricter requirements for exhaust noise (“Geräuschentwicklung”) were introduced Before this (late 1940s / early 1950s): Exhaust systems were relatively lightly
Read more »

This 13 mm screw cap, located on the bottom of older models of BING carburetors, is available with 3 mm of extra length. If the first threads in the housing are worn, preventing the original cap from being tightened, this longer cap offers a solution. However, this doesn’t apply to all carburetors with a 13 mm screw cap: in some models, the overflow channel is positioned lower, so the longer cap blocks it. In that case, the cap can be installed with approximately 1 mm of extra thread.  

Since 600cc cylinders are slightly taller than a 500cc cylinder, the cylinder heads will be positioned further out on an R60 and R60/2. This means the exhaustpipe must have a different angle to reach the same position along the frame. The R60, R60/2 exhaust pipes we supply are marked with a “6” on the crosspiece for the balance pipe. See photo. The absence of this marking does not automatically mean that it is an R50, R50/2 exhaust pipe: there are several manufacturers and they do not use this marking. Measuring the angle of the exhaust pipe can determine whether it is a 500
Read more »

a question that is sometimes asked: are all BMW inner Bowden cables provided with a (Teflon / PTFE) coating? The answer is: no, they are not coated, however, all cables have a POM sleeve inside which is self lubricating. POM = Polyoxymethylene or Polyacetal

The correct functioning of a capacitor can be measured with (for example) a FLUKE multimeter. The value specified by the manufacturer is 0.22 μF (microfarad). Over time, a capacitor’s performance can be expected to decline. The left photo shows a broken capacitor: the measured value is 0.131 nF (nanofarad) = 0.000131 μF The right photo shows a properly functioning capacitor: the measured value is 0.249 μF. This is 13% higher than the specified value, but this does not affect proper operation. The value specified by the manufacturer is a chosen ideal value for the expected average engine rpm. This value is therefore
Read more »

It’s a wide spread misconception that pistons must be round / cylindrical. The opposite is true, This is a new Kolbenschmidt R27 piston 68.50 mm:               From the Internet: Profile: If you roll a piston across a flat surface, you’ll notice it doesn’t roll in a straight line. This characteristic is called profile. Aluminum conducts heat significantly, so pistons are designed with a taper. The top of the piston (near the crown) has a smaller diameter than the bottom (near the skirt). The skirt itself is shaped like a barrel. This taper allows the
Read more »

The only difference between the Denfeld en Pagusa saddle is the saddle deck. There are small differences between the saddle deck frames: the shape of the frame and the front threaded bolt. The Pagusa saddle bolt it is a bit longer and has a spacer so that the front of the saddle deck sits +- 1.5 cm higher compared to the Denfeld saddle deck. The grain texture of the Denfeld rubber saddle deck surface is finer than the Pagusa grain texture. There is no quality difference All other parts are the same: subframe, Z-bracket, rubber spring, spring stop piece, mounting
Read more »

The Light & Horn Switch with P/N  61 31 8 048 162 does not properly fit on the Clutch Lever Assembly with P/N 32 72 2 072 112 The cause of this problem is clarified in the photos below. The ends of the switch housing extend too far into the clutch lever assembly. As soon as both parts are mounted together on the handlebar, the switch housing is pushed outwards, so that the switch housing can no longer be hooked behind the cam. Option: you can grind down the corners a little to make the housing fit. Because it’s a brass housing,
Read more »

Based on a sample of 74 gear sets, this graph shows the frequency of the different gear sets and the spread around the target dimension of +0.

Comparison of the different gearbox cam plates used in the R24 – R27 and R50 – R69S models. For more information about the R50 – R69S shifting system, click following links: Smooth shifting R50 – R69S R50 – R69S Old and New style shifter mechanism  

There are 2 versions of this spring cap available in the market. The top one is correct. The valve in the lower black spring cap is too deep, with the result that the force exerted by the valve spring is slightly less.                                              

A “strenght & weakness” overview of the different seal materials available in the market.