R51/3 – R69S engine gear set dimensions

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.

Gearbox cam plate comparison

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  

Upper valve spring cap 11 34 0 026 180

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.                                              

Seal material property comparison

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

Oil slinger screw

The oil slinger screws are not available from BMW anymore. Most suppliers now offer a general purpose DIN 963 M6 x 10 screw. However, the head of this screw is higher than that of the original screw: the head of the screw protrudes above the oil slinger surface. This may be undesirable in some cases. We now supply oil slinger screws with the same dimensions as the original screw.

Ignition keys

These photos show the difference between the Noris keys and the replica keys. This can help to identify the cause of malfunctioning ignition switch.      


All standard bearings we supply, are either from FAG or SKF. FAG is a brand of Schaeffler Group Germany. SKF is a Swedish company. Both companies have factories in different locations around the world. The country of origin is stated on the packaging. These can be countries like Portugal, Slovakia, USA, Republic of South Korea, India or China. We regularly have to explain that “made in China” is not a parallel import of Chinese brand bearings.               We purchase our bearings from ABF Bearings. ABF Bearings is a major worldwide ISO certified distributor of
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New cylinder heads R51/3 – R60/2

Our price of these cylinder heads is higher than the price of other suppliers, for the following good reasons: 1. The valve guides are checked and reamed if needed. Some guides require upto 0.02 mm reaming.  Without these adjustments, the valves would get stuck quickly. 2. We replace the supplied non-rotating valves with rotating valves. 3. The cylinder head mating surfaces are flattened in case of visible/palpable edges in the mating plane or “curved” surfaces. The depth of the mating surface is measured, to make sure that the height of the collar on the cylinder does not exceed the depth
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Turn signal switch & switch support

Turn signal switch with P/N61318048152AM will only fit with switch support with P/N32722072175. The original Magura switch support is too high, so the switch does not connect properly to the switch support. This leaves an opening visible.                              

Exhaust pipes comparison R25, R25/2, R26, R27

Without direct comparison, it can be difficult to distinguish the difference between the R25-R25/2, R26 and R27 exhaust pipes. This photo shows how you can easily determine the type of exhaust pipe:   The R25, R25/2 exhaust pipe is significantly longer at the straight end than the R26 exhaust pipe:

R51/3 – R68 Throttle assembly – sliding block design

For unknown reasons, the supplier of the after-market throttle assemblies for the R51/3 – R68 models (pn 32722072350), has decided the modify the design of the sliding block. The old sliding block used to have recesses to hold the cable ends, the new version does not. While in the new version the cables cannot “escape” either, the cable ends can rub against the inside of the throttle body causing unwanted wear. We therefore remove the new sliding block from the throttle assembly and add the correctly designed older sliding block. This however increases the price of the throttle assembly.  
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Saddle Y-frames R25/2 – R27 and R51/2 – R68

  4 versions of the saddle Y-frames are available: P/N 52 51 7 002 164:   R51/2 – R68      with 8 mm holes for saddle bearing bolt 52 51 7 002 125.7 P/N 52 51 7 002 165:   R51/3 – R68      with 10 mm holes for silent block 52 51 7 002 141 P/N 52 51 7 002 115:   R25/2                 with 8 mm holes for saddle bearing bolt 52 51 7 002 125.7 P/N 52 51 7 002 116:   R25/3 – R27      with 10 mm holes for silent block 52
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