Eddie, compression needs to be taken into account at some stage.
There is seemingly a resistance to modify the Head when fitting a Big Bore, so what is effectively a smaller Head is installed raising the compression and leading to problems both with Knocking and sometimes starting problems also.
I would suggest that if you did go for a Big Bore that you enlargen the combustion chamber so as to avoid this.
Have you checked the compression on your current set up?
IMO, You are getting about 4HP more than stock with your bike now, getting the next 4 or 5 HP is a bit harder but can be done.
There is seemingly a resistance to modify the Head when fitting a Big Bore, so what is effectively a smaller Head is installed raising the compression and leading to problems both with Knocking and sometimes starting problems also.
I would suggest that if you did go for a Big Bore that you enlargen the combustion chamber so as to avoid this.
Have you checked the compression on your current set up?
IMO, You are getting about 4HP more than stock with your bike now, getting the next 4 or 5 HP is a bit harder but can be done.