Hello all! I recently purchased a 1997 Honda CBR 600F3 with around 20,000 miles on it. About a week in, I was riding to work when I noticed that there was something wrong with the throttle response. As I increased the throttle, the engine would kind of die down for a second or two before picking up as normal. I thought it odd, but continued on, when I pulled in, I gave the bike a few revs with the same result before the engine died. It restarted but quickly died out again, and eventually it wouldn't start at all. I had to leave it there and carry on about my day, when I came back a few hours later. It started right up again, but wouldn't hold idle without the choke about halfway engaged, and when I would try to rev, the engine would die. I spoke with my Father about it, who is a lifelong mechanic on all things flying, riding, or driving. We decided it was most likely a dirty carburetor issue, so we pulled the carbs and cleaned them, although they were spotless, all pilot and main jets clear, bowls clean, and floats free. Perfect problem solved! I took the bike for a short ride before heading home that night, and she performed like a top! not a single issue starting, and the throttle would pick up at the slightest twist. I rode for about 30 minutes, including a stop at a gas station. I was about 3 streets from home before the previous issue started to recur. I would add throttle; she would bog and die, get restarted, then die just as quickly. After a lot of pushing, I got it home. I wasn't able to work on the bike for a few days after, but I did try to start it a few times with mixed results. The first two times, she wouldn't start at all, the starter would crank but no life, on the third day, boom, she fired right up. However, the rpm started to climb with no input on the throttle, and the rpm reached around 6000 before I hit the kill switch. I don't want angry neighbors! Then the same again on the fourth day. When I got some time, I went out and, with the never-ending support and patience of my Dad, worked through all the troubleshooting steps listed in the manual for fuel-related issues. Checked the air intake, filter, lines, and associated filters; all clear. Checked the air solenoid and corresponding relay; all good. The gas tank and interior filter were clean, and when switched to on or reserve, the petcock had a solid stream of fuel. We did find a fault in the fuel cut-off relay. With the ignition on and the kill switch in the run position, the fuel pump did not run. We jumped the relay, and the fuel pump was running, and the bike would start every time; however, the rpm would climb with no input from the throttle as before. When the new relay arrived, I installed it and the bike started perfectly, idled at 1200 rpm, and was very responsive on the throttle. Yay! Just as a cautionary measure, we reinstalled the old relay to prove out that it was my issue, but with the old relay installed, there was no difference in the performance. Ughh, square one again. I eventually caved and ordered a new fuel pump but that didn't fix the issue either. I'm posting this in hopes that someone may have encountered this vexing problem before, or you may have an idea for what to do next. We're stumped! Any help or advice you could provide would be enormously appreciated! Thank you so much for your time.

 

Hey there. Congrats on your new bike. Once you get her sorted out, you’ll love her.

I would venture that you still have dirty carbs. This is by far the #1 issue with the f3 after it’s been sitting. The carbs have to be fully disassembled and cleaned beyond throughly. It is a tedious task.
After that, they have to be synchronized.
There’s no short cutting this. Once the bike is proper, she’ll scream. Until then, it will be an exercise in frustration.

As to the fuel pump, on the f3, it doesn’t kick in until the bike is running.

There is a factory service manual .pdf in this forum if you need it.
There’s tons of threads here of folks who’ve experienced what you are currently. In almost every case, it’s the carbs.