Got round to doing my valve clearences today and a couple of the valves on the exhaust side were measuring as much as 0.36 (max is 0.28 i belive), is this common or should check and reseat the valves?

It depends on when the valves were last done and how the engine has been treated as to how much wear (gap) you'll have.

If they were done recently and you have such a big gap, somethings deffinatly wrong, if you don't know when they were last done it might just be a sign of neglect.

if they were done correctly previously the clearances would be below 0.28 on the exhaust, as the gap closes up with engine use, not expands. if someone made a balls up and made gap too big, it would explain this. for now i would just adjust your clearances to within the range, and if engine goes well with no probs, i wouldnt worry, however if you start having big probs with engine running, there is a chance that the valve has pettled with slamming against its seating on the cylinder head. thats worst case scenario though.

remember you are best balancing your carbs after doing the clearances, in case you mistake fuelling probs as engine probs

if i had to put my money on it id say they havent been done for some time, its a track bike so it does get some stick. I'll adjust them, balance the carbs and see how it runs