I would like to just throw a couple thoughts at this problem:
do you have a OBD cable port on the bike? assuming yes, have you or are you able to see the tune with Tune ECU?
If you are able to see the existing tune in the bike and copy it. If you send the .hex file I would be willing to take a look at it.
the other item to look at is the gear selection indicator, it may well be tied to the speed limiter. This is common with all makes of sport bikes (although they are limited at 300 kph) the limiters only work in the highest gear. The sport bike guys often fix this by installing a module to make their ECU think that the bike is in 5th instead of 6th.
to test this theory, just see if you can go faster than your limiter in 4th gear.
05 speedmaster - 1100cc, 11:1 racing pistons, Carillo rods, thunderbike cams, ported and polished head, 2mm over intake and exhaust valves, Barnett kevlar clutch, scepter pipes, oversize manifolds, 45mm HSR's, TTP stage 4 firestarter
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