2002 GSXR600. compression, leak down, injection, computer, fuel pressure/pump, cam timing, no wear on cam, new boots for intake to head just replaced, all are fine. BUT, I only get vaccume from cylender 4, the one on the far right. You can litterally cap your hand over the other 3 while it is running and it doesn't slow the motor one bit! what is this all about???????????? the back of the intake valves are blackened. vaccume leak? I pulled all the hoses off & nothing not a change. This is sure one thats got me and the mechanics stumped. no knocking or any funny sounds. I got out an incense stick and moved it all over the intake and engine while it was running and couldn't find any vaccume leaks.