Just bought a used 1997 CBR600F3. It was running fine for 10+ days (and for months before that by the original owner).

I brought it to a mechanic for a routine state inspection and to put some plastics and new mirrors put on. To get it state-legal they also had to put back on the gauge cluster and electronics--as it wasn't on the bike. After the work was done I hopped on and started to ride away. However, after 30 seconds I realized there was a problem.

After the bike gets around/above 4000-5000rpm the bike will *jolt* as if it's not getting enough gas or something. It'll run fine in 1st and 2nd gear but after that it it's unmanageable.

We thought it had to be the gague cluster (since it worked fine without it) -- but **when the gauge cluster was taken off for testing, the issue was still there!**

So far we (additionally) tried replacing the CDI, tightening the wires and checking for loose connections, putting in new gas & oil. It's a 1997 so it's not fuel-injected.

We also determined that the bike runs perfectly fine (at >8000-12000rpms) WITHOUT A LOAD ... but with any weight on it the problem is prevalent. The mechanic tested this by putting the back tire up and accellerating it.

Right now I (and the mechanic) are at a loss and have no idea what to check next. He says the problem has absolutely nothing to do with the work they did. I have a hard time believing this, but don't know how to prove otherwise...

Does anyone have any ideas about what could be causing the problem? Any feedback based on experience would be helpful!!

 

My first question is does it have a K&N air filter in it ? If it does, put a paper one in it and take it for a ride and let me know.

 

Dosnt this sound like the air solenoid that changes the flo of air at like 12mph? Someone else on here had a similar problem like this when they swapped gagues...

 

heres what im thinking of


https://cbrforum.com/forum/cbr-600f3-17/fixed-flat-spot-5k-rpm-101283/

 

Yes but he said he put the original factory gauges back one, or that's what I took him to mean. It's certainly worth a look.

 

Im not sure if there is a K&N air filter in there but will check and see asap.

As for the gauge cluster -- yes it's the original stock one on there now. However, as mentioned, the problem persists even when it's completely taken off alltogether. Any other ideas worth trying/looking into?

 

if its bucking and cutting out i would look into the fuel pump. ran into this before. just a heads up.