Yea, it's a pita with no spark. Pretty easy though, comes from magneto, goes through sensor (green plug under seat) then into ignitor box, into coils to plugs. Pretty basic circuitry.
Matt's Speedmaster is doing the exact same thing you describe and we swapped ignitors, his bike then ran great and mine would not fire. Switched back and the problem was back on Matt's bike. Problem successfully diagnosed. Beware...the parts is over $500US!!!!!!! Try to get a warranty replacement - beg/plead/cry whatever helps.
