I have a 92 cbr 600 an it bogged out on me and won't start backup. it turns but just wont run. i was told it may be my timing chain. i took the intake off and three of the valves are stuck closed and the other is open. i put a little gas in the fourth and got some back pressure. could it be my timing belt or if not does anyone have any suggestions on what to try?

 

Have you check to see if your plugs are fouled? Start simple.

 

Start simpler. Check the gas tank. Check the reserve switch.

Edit: I'll provide comic relief before the people who actually know stuff get here.