Hi. I'm new here and I need the Dr. House of bikes. Here's the deal- 1995 CBR 600F3. Starts right up, idles fine and even revs up in neutral, but when you put it in gear and twist the throttle, it runs up through first, shift to second and it begins spitting and sputtering like it's running out of fuel. (Fuel tank is full and pet **** is open). What I've done so far- had the spark plugs checked, carbs taken apart and cleaned (Stock carbs with stock jets), checked the fuel pump, changed the fuel filter, changed ECU, and checked the ignition coils. By "Checked ignition coils", I mean all the spark plugs are sparking. Air filter is dirty, but not dirty enough to cause issues and even if it was, these are obviously not air filter issues. The only other oddity is that the issue seems to be sensitive to outside air temp. 50-60 degrees or so, it actually runs okay, but once the outside temp gets over 70 or so, it starts acting up. HHHEEELLLPPP!

 

One other thing- It started acting up with fresh fuel in the tank and I also drained and refilled the tank, so I know it's not bad fuel either...

 

Did you check your charging system?

 

no. I know the battery charges and the headlight is nice and bright when the motor's running, so I assume it's okay... I read on another forum about a guy with identical issues and it actually ended up being because the air filter was dirty. Maybe my statement of ''obviously not an air filter issue'' was misled. Outside air temp would also make sense considdering air density at those temps. I'll run it this evening without an air filter and we'll see...

 

Is the bike warmed to normal operating temp? NO CHOKE.

 

It does it no matter what the engine temp is. I just tried taking the air filter out and running it without it... No change

 

I found something that might help, it could be the air valve not switching over with speed like it is suppose to..... Try this and see what happens, wouldn't take long to do

https://cbrforum.com/forum/cbr-600f3...5k-rpm-101283/



look threw the post's and you will see what i'm talking about

 

my possibly answer comes from the car world since i am new to bikes....

but it may help.

is your fuel pump working properly?

the pump may be pushing enough to keep the bike running at idle, but may not have enough power to push fuel fast enough to keep it running longer at load. fuel pumps can be funny and flow enough at idle, but not strong enough to meet the demands at load. first gear could be emptying the fuel filter, and the pump cant keep up after that.

just a thought and hope it helps.

 

im almost positive that is the root cause. either that or his gauge plugs are loose...that'll do it to, exact same problem, different source

all you have to do is unplug the white 2-wire connector on the right side of the bike. along the outside frame rail below the gas tank

 

Should also take the back of the pump housing off and verify that your contacts are good.