Front tyre wear pattern - suggestions.

The original D208 front fitted to my ZX12 is just about shagged after only 7500 km. There is also an unusual wear pattern - it is a bit 'lumpy', that is some high spots all round the circumference. Not huge ones but you can see & feel them. I had the same on my previous ZX12 with a Pilot Power on the front. A friend reckons it may be because I am either loading up the front too much or not enough and should be resolved by making some suspension adjustments. I've never touched the suspension since I've had the bike. I always run 30-35 psi so pressure is not the cause. Any ideas? Thanks in advance.