Thanks for all the feedback.
I asked him today to clarify what he was talking about, and he said the following.

The XTX accelerated well until he went into a corner then it just cut out. He tried it again and it did the same thing again. He says that he has ridden lots of bikes like an XTX and that they should rev more freely and higher than mine.
Lastly he thinks it is running too rich and it sounds like it is back firing allot.

So a couple of points;
The bike previously has cut out twice on me, however I had put in one fill of 91 ULP. Since then I have used a min of 95 RON and never had an issue.

Personally I think the bike revs freely and I don't have an issue with it. That said this is only my second bike and I do not have allot of experience to compare it to.

The bike does pop and fart quite a bit and it is quite loud (thanks to the Staintune pipes), which I think sounds great and once again do not have a problem.

That said can any one tell me the approximate max speed in each gear before changing up?