Twin plugging is definitely an improvement on power and economy 1990 I did it and since then I've been averaging 200 plus miles to the standard 15 Ltr Tank 3.25 gallons. 240 miles was my best ever but light loaded and didn't break speed limits, I have an aversion to service stations where they charge extortionate prices and usually to get to destinations quicker as I haven't stopped to refuel. Dick Powell from Braunton did a lot of miles behind the iron curtain (before 1990) 350cc AJS or Matchless used to do 400 plus miles between refuels, left a ferry once with other groups of bikers when he did his fuel stop there were three other bikers fueling and they looked him up and down and said we don't believe it stating that this was their third fuel stop on their multi-cylinder rockets, Dick told them it was his first !!! tortoise & hire story. My ignition is a Grosset with a manual lever also. as pinking can be present at times so if it occurs I can retard, even more, 24 to 25 degrees, with two sets of double-ended coils splitting them between the cylinders as one to each cylinder can be a problem if incorrectly manufactured, but the other way with splitting them one does not know if a coil has failed as both cylinders are still firing but too far retarded, overheating, ended up with a dropped valve seat in front pot and a 20mm hole in the rear piston yet still wasn't breaking speed limit.
bananaman.
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