T H E  O L D  G R E E N  B E E M E R RIDING A 1974 BMW R90/6 FLAT TWIN

POINTS? IGNITION SETTING I like points ignition for simplicity and reliability. As long as you stay away with file and sandpaper to " touch 'm up" they will serve you a real long time. 50.000 km at least, just keep the cam lightly oiled, every now and then a tiny drop of motor oil is enough. There is no need to file the points smooth in order to measure the gap, just eyeball about 0,4mm of clearance and all is fine. This engine is not critical on points dwell angle at all, so don't worry. Points ignition: Simple, Reliable and easy to fix. By the way, two types of springs are available for the ignition advance mechanism. Normal and stiffer, the stiffer ones let the advance weights fly outward later in the rev range and so make the bike easier to drive very slow like in parades for example, or trafic jams and they make the bike feel more locomotive in the low revs. Setting the timing is done by rotating the ground plate. The length of the cutouts in the ground plate determine maximum adjustability, but you are free to make changes. If for some reason you run out of room to adjust, what can happen if you are using points of an aftermarket brand and are contemplating to modify the cutouts, first try this: Just alter the points gap to a slightly wider setting as long as you don't go overboard in doing so, 0,6 mm is accepatable. Just realize that increasing the maximum opening wil have an effect on the lifespan of the lobe that rubs against the ignition cam. Larger opening - longer contact - more wear - theoretically. ! Again do not forget to keep the cam / lobe lubricated ! I never use a strobe light to time the points anymore as most of the old boxers do not give a good sharp image of the flywheel timing mark. The double image you can see on these bikes can be caused by an ignition cam that is slightly off 180 degrees, or the ingnition cam is too loose a fit over the camshaft, or the camshaft itself is not straight. My bike suffered the first and I have regrinded one the ignition cam lobes. Practically I see no need for a strobe light, I use an analog multimeter instead, reading Ohms. The ignition switch can be left in the off position. A piece of cigarette paper can also be used to time the points but unfortunately only on a relative new set, as these contact surfaces are still smooth. Continue to Computer Aided Ignition Tuning Back to BMW R 90/6 maintenance index / Home IT rev 2021 A A R D  V A N  H O L L A N D . C O M