I have a 2004 CBR 600RR and it is not running correctly. The bike cranks almost instantly and will rev to the red line, but the 2nd cylinder is cold the the third seems to be cooler than the outside 2. It is also very low on power and when given full throttle on the street it bogs. Once warm it cuts off at low rpm but will crank right back up. I changed the spark plugs and checked them and they seem to be firing great. I took the top fuel injector rail off and switched the number 1 and 2 injectors and the number 2 cylinder was still cold. I checked the resistance across all the injectors and they were all good. The bike sat for a while and I think the fuel system is backed up somewhere but I dont what it could be. I am a college student and this is my only means of transportation if anyone could help me that would be wonderful. Thanks to anyone for any help.

 

sounds like you went in the right direction with your diagnosis. A bit more information might be helpful though.

How many miles on the bike?
Any mods to the bike?
Ever been in an accident?
Has it just started to do this? or did you get it like this?


If you think its fuel related. You could run some seafoam through it. That stuff works wonders on fuel systems that have been tarnished. But it would be strange for only those cylinders to be firing less frequently. The reason I ask about the mileage is also because if the valves were out of adjustment, it may act this way.

Since it sounds like you know how to read resistance, I would check the resistance across all of your coils. A weak coil can cause all sorts of problems. If you can't find the spec, just measure all of them and compare them. Also, the inner coils tend to run a bit hotter, so it would make sense if the inner coils are failing, but not the outer ones.

 

There are 16k miles on the bike and I got it this way. It has been laid down on both sides but still has the original handle bars, just missing the bar sliders. It also has the original side cases and they show scratches, but they are not very bad. There are some more things that make it look like only slow speed low sides. The computer system is stock and the only bolts that appear to be touched by a wrench coincide with wreck repairs. It does have an aftermarket slip-on which I highly doubt is the problem. Tomorrow I will check everything and report back. Thank you for the help man, I really appreciate it.

 

I checked the resistance across all the coils and they are all the same. I just switched the coils from cylinders 1 to 2 and it ran the same. The number 2 and number 3 , the center 2 cylinders, still had cold exhaust. I took the plugs out and they have fuel on them but there is no sign of combustion. All the cylinders have good compression so this makes me think there may be a problem with the air to fuel ratio.

 

If your seeing fuel on the plugs, they are probably fouled. One other thing to check is the pulse generator. Since the bike was layed down, it may have been damaged. Its basically what tells the coils when to fire. However, I don't know if it would only affect the center two. Logically, it should affect all of them, but its possible its weak and not sending the "fire" signal consistantly at those points.

I know you changed the plugs, but if they have ever been fouled, they may not be any good. These plugs are very tempermental and even fouling them one time can cause them to intermittenly fire.

I know its a pina, but I'd also swap the plugs from the inside to the outside and see what happens. you may just be dealing with a couple fouled plugs.

Do you have communication with the previous owner?

 

I switched out the coils, spark plugs and injectors from the not running cylinders to the running ones and it makes no difference. All of the cylinders look like they are getting good fuel and spark just not at the right time. I was beginning to think it was the ecu but the pulse generator is definitely something to look at. Any idea how to check it?

 

Also If I take the bike and get it plugged into a computer at the honda dealership will it tell me anything? Would it be worth the money?