Hey,
I have a 2000 honda cbr600f4 and one piston isnt firing. Its the piston on the far left when you are sitting on the bike. I have cleaned the spark plugs. Im not sure if it is the carbs or the plug coil or maybe the carbs just need to be synchronized, im not sure. You can see that all carbs are getting fuel but when you give it throttle at idle the bike makes a girgiling noise and it sputters then goes up on the rpms. It isnt as bad when it is warmed up but you can feel the exhaust pipes and all of them are hot and that one on the far left is just warm. I unplugged the plug coil on that piston and it made no difference so it seems as if it were not getting any spark atoll. If you could help me it would be really appreciated. Please help. thank you

 

I'd pull the spark plug and the coil and test to see if you are getting spark. Just ground the spark plug to metal on the bike and see if it sparks. If it does then you have a carb or compression problem. I'd do a compression check next - compare it to your other cylinders. If it's low you could have a bad valve or bad rings. If compression is fine, it's most likely your carbs. Start narrowing it down.

 

The worst case scenario is that you have the piston gripped. But... i don't think its the case.

My advice is to put 5-6 drops of engine oil into the cylinder over the spark plug opening; clean/change the spark plug and try again.

P.S:the carbs are out of the question ( don't waste your time searching problems at them)