yzf 750 need help

Hi guys ive got a 1995 yzf 750 r ive got the usual missfire question but ive tried just about everything.

Was missfiring up about 9k but when it gets hot im loosng a cylinder all together.

Ive had the carbs off and cleaned them fitted new carb rubbers, new plugs , new ht leads and swaped coils with some that came with the bike but i dont know if these were any good.

The exhaust was swapped as well because ther was a hole and the second hand one i got came with an exup valve and it moves freely.

Just about to buy a new set of plugs just incase i have a bad one the i was thinking new coils.

any ideas?????????????

on another note does anyone know where i can buy original tank decals or vinyl sheeting to replace the originals that got knackered when the tank was lying on its side and petrlo leaked on to them .

I dont want to have to spend loads the bikes not worth it.

thanks alan