Bought a ZXR750 yesterday,rode bike home (55 miles) but on the way home tonight I opened her up just a little at about 40mph just to pick up to 50 mph and then all of a sudden bang bang bang,noise is engine speed related,no extra vibes,thought it was exhaust manifold blowing so checked with a torch when I got home (10pm) cant see anything obviously wrong,did sound similar to an engine being run with a spark plug missing and is coming from the front of the bike,seems to still idle ok apart from the noise,any ideas,got bike off ebay so I'm a bit stuck,gonna whip the tank off tomorrow so if anyone has any idea what I should be looking for I'd very gratefull Cheers Dan