Triumphrat

hi, i put a pvl analogue electronic ignition in my T100R runs great
for 15 minutes, 17 if i take it easy. then backfires, coughs, stutters,
and will only idle. once cold i can run it trouble free for another 15 minutes. high tension coil, stator coil, electronic box and rotor do
not get hot. ground is good, plug color good, initial timing set at triumph's 38 degrees BTDC. carb clean, fuel tank and filters clean.
pete