I tried this on the /2 site but the Airheads may be better because of the modifications. Bmw R69s 1966, 12 volt battery/coil, Harms points plate . I have owned it for 8 years. Always ran well. New pistons and bored out, heads redone- all done 250 miles ago. It ran well until it started to miss a beat or two at steady throttle. I rebuild carbs and cleaned the petcock, put in new points, plugs, put in spare coil, set timing, adjusted valves. I have switched plug wires and the right side still is not running well. It starts right up. What it does, it back fires, will not take throttle, right side heats up only a little, plug is black. At this point I wonder if there is a problem with the new bore out pistons and valves, ---an air leak? ( I did a spray test for leaks but did not see anything) Trying to get it running for the MOA Rally in a few weeks. thanks Jim