CBR 600F Starting Problems

Paulk · 09-29-2007, 3:23 PM

Hello everyone,

I have a CBR600F 1995 model. I have had problems starting for a few months and put it down to bad fuel. I have changed the plugs, oil, and removed all of the old fuel from the tank and lines. I add octane boost to 98% unleaded fuel and it ran for a few days. Now the bike starts but only runs for about 3-4mins until it is hot then stops and will not start again. I have to wait until the bike cools down which is usually the next day then try starting it again. Before it stops it will not idle and has a very rough rattle sound to it like a lawn mower!!

Any ideas what the problem could be? I have had a few guys say it is the coils which need replacing and someone also said it was the CDI box. Has anyone else had this problem?

Paul.

dattaway · 09-29-2007, 3:57 PM

Replacing all the coils in the world won't fix a clogged fuel system and jets.

Paulk · 09-29-2007, 4:07 PM

Hi Dattaway,

The fuel system has all been cleaned and also had a cleaning fluid mixed with fuel run through the system. I have run a tank of fuel through the system since replacing the plugs, oil, and removed all of the oil fuel from the fuel lines, etc. The bike just keeps stopping after about 3-4mins of running and will not start again until it cools down. I have never had this problem in the past. Strange???

Rider · 09-29-2007, 8:31 PM

fuel tank breather is blocked.... try running it with the fuel cap open to see if it will stop again...

or better still, unblock the fuel tank breather. Maybe the tube is kinked somewhere...

Paulk · 09-29-2007, 9:25 PM

Hi Rider

Just tried starting/running with fuel tank open and ran for about 2-3mins until warm/hot then started to sound really rough and even though I had the throttle and rpms at 5,000 it slowly died and stopped running. Will now not start again. Tries to start but its like to spark getting through to the plugs.

dattaway · 09-30-2007, 10:03 AM

A guy I worked with recently cleaned his carbs trying to fix the problem you described. "It ran rough until it warmed up and died." It sounded like a fuel problem, but he bought new coils as recommended by the dealer. That didn't work and I finally convinced him to take off the carbs again. Not only did he fail to pull the jets out to clean underneath where the real varnish was, one of the diaphrams was ripped. Rather than buying a rebuild kit for each carb ($100 EACH) he bought a new bike. And he lets his new bike sit for weeks at a time, letting fuel dry up in the carbs again...

Rider · 09-30-2007, 8:14 PM

dattaway is a wise man. maybe you should try to clean/rebuild the carbs.

sorry that my suggestion did not work...

you say that the fuel system has been cleaned. Does that include the carbs? As Dattaway suggestes they can be tricky to clean and inspect properly....

Paulk · 10-01-2007, 12:42 AM

Thanks Guys I'll try it and see how I go.

baxsom · 10-07-2007, 12:40 PM

i am running into the same problem with a F3. it starts for a second or two then stops. if you drip a little fuel into each carb it starts right up until it uses those drops up.