The problem I have is getting to the route cause. It doesn't run hot and there is a nice layer of oil in the pipes. I had it on a dyno recently and it was running slightly rich at the top end (before the new pipes), so I don't think it is running lean. One thing I have noticed is that the battery was nearly dead after it had stopped. Could a failing battery have caused the issue? Fueling/Ignition may be aaffected by this??
Next step is a full top end rebuild. Do these engines typically destroy the bores, or is it likely to be just pistons?
Any advice on a top end rebuild would be most welcome. Tips, people to repair bores, replates, etc etc. I am a bit gutte at the moment and could do with some support from my NSR bretheren

Thanks.