Forum bmwbike.com

Dear Friends,
which are the main problems caused by a centrifugal governour failure ?

how can be made a correct diagnosis of that ?too big play in the centrifugal masses could affect his right work ?

any more explicacion will be appreciated.
Michele

I am not sure what you mean by "centrifugal governor". If you mean the spark advance unit mounted in front of the magneto failure would make the spark advance irregular. Check this with a timing light and see that the flywheel marks move smoothly from S to F as the engine increases speed. If the spark advances beyond the F mark you will get "pinging" because it is too advanced. I don't know if these units are adjustable or rebuildable.

You might mean the dynamic ballance mounted in front of the generator on the R50S and R69S. If the rubber is worn or the ballance is missing the crankshaft could break at high RPMs (it happened to me).
Good luck,
Drew

Greetings Michele,

If the ignition advance mechanism is not working correctly, the timing will advance and retard in an irregular way. If the springs are weak or broken, the timing will advance very rapidly as you open the throttle, and can stay advanced as the engine tries to return to idle, keeping the RPMs too high. If the weights are not rotating smoothly, the advance can stay too retarded and then advance quickly, and possible stay advanced for too long. The weights need to be clean and lightly lubricated so they move smoothly, and the springs need to have the correct tension to allow the weights to move out and come back correctly. In addition, the points cam needs to rotate smoothly in both directions. If your advance unit is in generally good condition and not physically damaged, you can probably clean and lubricate the moving parts and replace the springs.

Best wishes,

Dave

I was told the centrifugal advance unit in my R60/2 is worn.
The springs are weak and even after adusting the tension, they show too much advance at high rpm, but I use 93 octane gas so there is no pinging.
Also, the holes or slots in the unit are worn irregularly, so that the fast timing mark shows in a different position if the pickup is placed on the left or right spark plug wire. This probably causes an imbalance in firing, which could explain the vibration that I feel in the motor at the same high rpm in each gear.