Thanks mate. That was a good read. As it happens 155 main jets are what I settled on as well and the top end is good. The conditions here in Brisbane are probably similar to your neck of the woods so it's not surprising. I'm seeing all the same things you saw with stock carbie parts. On the needle it a seems way rich so I plan to try the leaner HRC needles. What interests me is the mixture at 7k at WOT. The bike did multiple dyno runs. The plot I attached is WOT and it is way lean at 7k. I'm thinking these HRC X/Y joints must make quite a bit of difference and it's likely they allow less air into the engine than the stock X/Y joints?