They are cool bikes. The older bikes don't have a bunch electronics and are simpler
to work on. Also the shaft drive is neat
The R69S still uses points and condenser. I tried to replace them with an electronic controller, but the lightened flywheel on the bike threw off the timing when kick starting, rendering it useless. The coil isn't in the best of shape, either. A very good friend gifted me with a standard flywheel, but before I could install it, something went bang in the engine and now only one piston goes up and down. Fixing it isn't a priority right now, but some day...
Post 1980, BMW went to a Hall Effect trigger, which they placed where the points were located, at the front of the engine. There were problems with shortened life due to the heat, and the unit was inadequately protected from high voltage surges if one forgot to connect a spark plug. Fortunately, several after market companies have come up with better replacements. I'm using one that has an optical diode to sense crank position, eliminating the vagaries of the factory cam triggered unit, and is immune to the voltage surges and heat. It even has an LED that comes on when it thinks the crank is at TDC, which makes timing very easy to set. And it has multiple advance curves, one of which is good when another spark plug is added to each cylinder. That setup uses less advance, so it allows the use of regular octane gasoline even at higher than factory compression ratios. Anyway, the rest of the electronics is an old fashioned wire loom and mechanical switches, a far cry from the computer networks found on the modern bikes. Except for the turn signals, which are controlled by an over complicated pile of resistors, capacitors, chokes, and other junk that also fails prematurely. There's an aftermarket solution for that, too, that features auto turn signal cancelling.
The last generation of the airheads featured two u-joints in the drive shaft, with a rubber damper in the middle to cushion the drive line. Unfortunately, the buffer would slip and the two u-joints would go out of phase, resulting to premature failure. Again, there's an aftermarket alternative that is bullet proof, and costs less to replace than the factory part. I don't miss chain maintenance at all.
The Earls fork design was especially good for sidecar use. The R69S frame has mounting lugs for a sidecar, but I doubt they'll ever get used. In the late 60s, BMW put a pair of telescopic forks on the R69S and called it the R69US. Not as strong as the Earls setup, and the handling wasn't that great, either. It's amazing BMW continued to make the air cooled twins as long as they did, especially after Honda came out with the CB750 in the early '70s. Thank goodness for stubborn Germans!
Do you still ride motorcycles?
