Thanks Guys for your reply, I'm going to check it out today.
Was just thinking as I think I had similar problem a few years ago with my 748 and it was a goosed battery.
I got fuel drove roughly 9 miles then at mot lights on horn on then about another 4 miles the misfire started.
So for 13 miles after putting in fuel the bike was fine.
What you think could a new battery help?