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Staburag is a good alternative for “Prussian Blue” when determining the contact pattern between the crown and pinion gears. By adding a few lines, the contact pattern becomes even easier to read.                  

The R69 flywheel differs from the other / 2 flywheels because of the position of the ignition marks:

A comparison of the required shifting force needed, between the old and new style shifting mechanism.                                                                                      

Link to the original post: https://blog.scottiesharpe.com/2013/03/bmw-2-swing-arm-leaks-final-drive-leaks.html?m=1 BMW /2 Swing arm leaks, final drive leaks During a routine oil change, it was noted that the drive shaft housing was empty.   Could it have been stolen by vagrants?   A guy works hard for his oil just to have vagrants come and steal it. Well, before contemplating a move to a safer neighborhood, BMW riders should remember that oil migration from the drive shaft housing to the rear drive is a common problem. There are three ways that oil can migrate from the driveshaft housing to the final drive and they
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Valve springs can lose a lot of their strength over the years, as seen with this R25/3 valve spring: a new spring measures 16.6 kg, the old spring 10.1 kg, almost 40% lower. Lower spring tension usually causes no or minor problems on low revving engines, but it can lead to loss of power / misfiring on higher revving engines as a result of valve float                 The test device:  

Comparison between the “old” and “new” version of the R50 – R69S shifter mechanism. Click following link for a comparison of the cam plates: Gearbox cam plate comparison

The number stamped in the crankcase (from -10 to +10) refers to the size of the crankshaft and camshaft gears installed by the BMW factory. After 60 – 70 years of service, the crankcase may have grown, which means that the original gear set may not be the optimal set anymore (0.01 to 0.02 mm play between the 2 gears). One way to determine the correct gear set number is to measure the c-t-c distance between the crankshaft and camshaft. This value must then be compared to the nominal c-t-c distance. This is impossible without very accurate measuring tools. The difference in
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A comprehensive list of bolts, nuts and washers for the R50 – R69S models Click image for list :                          

Recommended press fitting for valve seat inserts in aluminum cylinder heads: OD insert 30 – 40 mm: 0.15 mm / 0.0059″ OD insert 40 – 50 mm: 0.18 mm / 0.0071″   Spindle speed for cutting a seat pocket in aluminum cylinder heads: 400 – 600 rpm It’s recommended NOT to freeze (f.i. with liquid nitrogen) the sintered valve seat inserts before installation. The valve seats are to be pressed in with a flat and square seat driver tool. The valve seat is inserted with the radius side down.   Source: DuraBond

Some statistics based on last 5 years (2013 – 2018)      

There is a clear length difference between the side stands for the R50 – R69S models and the R50US, R60US and R69US models (due to different configurations of the front fork) These are therefore not interchangeable.

All Matra tools with spindles such as M355, M499 / 1/2, M422a, M501 and M282 work much better (more smoothly) if a small amount of lubricant (eg Molykote G-n Metal Assembly Paste) is applied to the thread. This prevents galling of the thread under heavy load and reduces, to a certain extent, unwanted rotation of the other part of the tool.