mk1 1200 wont rev past 8k rpm in top gear

I had a mk1 1200s bandit in 98, did 141 mph in top gear with a 14t front sprocket, revving to the redline in top. I now have same model bike, italian import, does 140 mph in top gear at 8krpm again with a 14t front sprocket, but wont rev to the limiter, anyone know how to deal with this? Paul