I just bought an 02 f4i. It's clean, with 20k miles. It ran great when I bought it. After a day or 2, it started having a misfire and I could smell the fuel rich exhaust. I will mention there are no f1 lights. I pulled the air filter and it was the worst air filter I ever saw. I replaced it with a new k&n. It ran slightly better. I ordered new plugs. When I pulled the old plugs, they were all pretty black, and the one was clearly fouled. It was wet, and you could smell the fuel. I put new plugs in and it ran so much better, but it still hesitates when I first take off to a point where its sputtering no matter how much throttle I give it, until around 2500-3k rpm then it clears up and takes off. Then when I'm cruising at like 5500-6k rpm holding a steady throttle, you can hear the exhaust sputtering Instead of that crisp smooth sound. I just bought a new fuel filter, waiting on that to come but I'm lost on what else it could be. I was thinking maybe FPR but dont want to spend $70 on a OE Honda fpr for it not to work. I don't want to keep throwing parts at it aimlessly. Any ideas on what troubleshooting I could do to try and figure out the issue so I can fix it without throwing tons of money at it would be greatly appreciated. Thanks in advance!

 

Is there fresh fuel in the tank? any rust inside the tank?

 

Fresh fuel, no rust. The guy before me ran some fuel injector cleaner through so maybe something dislodged and clogged up an injector but I would think it would steadily run messed up. I heard before after a bike is dropped on its side, sometimes the fuel filter acts up so I'm hoping when I put the new fuel filter on it helps. I'll be doing that in the next day or so. I don't know how to check Injectors or I would pull them and check them. It really sucks though bc starting out at lights, the bike just sputters then takes off and it sucks when I'm turning at a light. It's borderline unsafe.

 

Could it be something to do with the clutch? My bike also does this once in a while if I let it out too quickly it sputters and the bike shakes and doesn't get power until 4-5k. I know how to use the clutch obviously but lets say I'm attempting to race someone, there's no way I can start from a stop. Tried going against a tesla and he got about 100 feet infront of me before the bike even started making power lol.

I am curious to see what you find out!