My buddies GSXR1000 has about 4000 miles on it and is now running crappy. He says it feels like he lost a cylinder. Only mods are PC and Yoshi pipe. Disconnected the PC and it still runs badly. He checked the spark plugs and they aren't fouled but he didn't check to make sure that they were sparking. Personally I think he lost a coil pack.
Somebody on a GSXR board told him something about a sock (?) that needs replacing. You guys ever hear of that? I know on the old Busa's they had problems with screens on the pump and injectors -- wasn't sure if the GSXR's suffered from this.
Appreciate any help.