Originally Posted by _cy_
Bulldust, pretty slick system ... but track history indicates very low instances of mechanical advance failures on airheads. let's say one does develop sticky advance weights. odds are motor would not run optimally, but it would still run to keep you from walking.
solution is usually a spray with WD-40 or other penetrating oil and you are good to go for many more miles. this would fall under preventive maintenance before a long trip.
modifying your own BMW beancan by adding an extra Halls trigger only costs about $20 and not that difficult with proper tools. while you've got beancan torn down, that would be the time to relube mechanical advance.
carrying a spare ignition module takes little space and are not that expensive. then replacing problematic 12v Bosch coil with high performance Dyna coil. for a total cost of about $150, includes spare Halls trigger, new Dyna coil and spare ignition module.
I see no reason to carry parts that have a long history of next to zero failures. or come up with solutions for non-existent problems.
if one was racing, huge advantage with electronic ignition advance of being able to change ignition curves. not so much for adventure riding.
thanks for pointing out full redundancy of twin plug ignitions. would R80G/S gain any performance with it's low stock compression ratio and dual plugs?
I have found a significant performance advantage in replacing the original mechanical advance system in my BMW's so have all of my friends who have installed my system. Better starting, a much smoother engine, and significant low end torque increace. Older bikes have shown significant wear in the advance weights and springs, throwing off the original design ignition advance. One of my friends noticed that his 1994 R100GSPD was like a totally different bike after fitting the system, much smoother and stronger engine when two up and heavily loaded, he commented that he no longer had to shift back to 4th gear when passing Road Trains (real big Australian Trucks with up to 3 trailers).
Full redundancy in twin plugging is dependant on wiring setup (I once had a rock thrown up by a truck smash one of my plugs clean off. I did not notice till I stopped for fuel some miles later). Nice to know if a coil fails it will still get me home too.
Not sure about a Low Compression R80G/S getting any performance advantage from twin plugging, would not hurt it. Most of the R80G/S's I know of have been converted to 1,000cc bikes in Australia and then twin plugged.
I have 4 of my Airheads twin plugged, 1978 R100RS, 1982 R100CS, 1990 R100GS, 1996 R100GSPD (1070 kit). I find they get about 5-10% more power, better fuel consumption and a smoother engine, all but the 1978 bike are fitted with my ignition system so they run a lot better (and cooler) than stock, the 1996 R100GSPD with the 1070 Seibenrock kit (long rods, cam etc) is fitted with early model RS heads and runs very hard.