Thanks to all who takes the time to reply with help! I had a past mid life crisis and bought a 2000 cbr f4 that had been sitting for about 6 months. I can't get it to start, it will run when gas is trickled into the carb throats just fine. The fuel pump pumps 36 oz. per min. gas is getting to the carb y connector but bike refuses to fire unless choke is used, then it will spit and sputter a little. I have good spark at the plugs and engine will run real smooth when force fed gas with a squirt can. The fuel pump will not run with key in the run postion, but I have jumped the fuel pump relay to make pump run with key on. I think the relay is bad but that is another issue that I can address if I can get it to start and run. I cut my teeth on a 1969 and a 1970 CB 750 and could make them run just fine, but this new stuff has me stumped. Do I need to remove and clean the carbs, it looks like quite a task and I don't want to tear up more than I fix up! I have used sea foam in the carbs without any luck. Please help, I would like to get a few more thrills out of riding this rocket before I give it up for good!

 

the relay needs to be changed for sure. on this bike no gravtiy is needed these are flat slide carbs. the fuel pump does most of the work(which is why almost all have gone out at some time). but check the lines to the carbs the i.d. is very small and it could clogged or completly blocked by geled fuel if has been sitting around in cold weather for a while and also check you throtle postion sensor on the right side of the carb rack. make sure the connections aren't corroaded. sorry cant spell. also on thi sweb site is the f4 manul in .pdf format. and if prolblems stil prsist take the carbs off and find a local shop with sonic cleaner. it's just like the one you use for jelwery but bigger and it will knock out any thing in the carbs

 

What up Old School!! - I don't remember the fuel pump running on that bike unless the engine was started (i.e. it doesn't pressurize the lines like a FI bike).

My money is on the carbs. F2, F3, and F4 carbs were notorious for gumming up when gas is left in them as their passages and such are reportedly even more nano-sized than some other bikes.

Its not that big of a deal to disassemble them and de-funk them. As I recall, you don't even need new gaskets and such b/c most all mating surfaces have groove/o-ring type sealing. Once you have the bike torn down past the air cleaner housing they're almost off.

If you need the manual, I have each chapter in .pdf format. Shoot me your email and I'll send it to you. - VE

PS: FWI, I forgot to put Sta-bil in an F3 before the winter one year and it clogged up on me so bad the only way to get it running again was to remove and soak the carbs for 48 hours. I must have tried 5 different fuel cleaners (even eye droppered them right into the bowl vents) but none worked.

 

When you turn the key on the fuel pump should prime for a few seconds just like the FI bike. The difference is pump location and pressure. If the fuel pump doesnt come on when the key is on but runs when jumped then replace the relay. Jumping it can over power the needle valves and flood the engine out. If your getting fuel to the y connector and assume that its stopped up carbs then it will be hung needle valve or blocked fuel jets. hold the throttle wide open to verify its not flooded and a little ether wont hurt to get it to run and start drawing fuel again. I've dealt with so many different fuel issues on my f4 over the years I could ramble on about possibilities all night.

 

I bought my F4 about 9 months ago with the same exact fuel symptoms - it wouldn't start but it would RUN. I pulled the carbs off and cleaned them and the thing has run great ever since. The low speed jets are incredibly small and it wouldn't take long for them to gum up.

Like JONLD said you will hear the fuel pump prime for a couple seconds when you first turn the key assuming they kill switch is in the run position. The pressure is a very low pulsing so don't expect it to shoot across the room.

There is a write up on carb cleaning on here, but if you have some basic mechanical skills you will find it to be a relatively easy job. DO NOT SPLIT THE CARBS, they will then need to be re-synched. Just pull all 4 off as a whole and clean them. While you have everything apart I would take the opportunity to replace the plugs, and thermostat since it is all right down there....

 

Well I finally decided that removing the carbs and cleaning them wasn't such a big deal, more fear of the unknown than anything. I had to make a long phillips driver to reach the clamp screws, but got along fine. The carbs were gummed up real bad, after a complete dissassembly and cleaning of all the jets and bowl the bike runs like a watch! The speed that the engine reaches max rpm is unreal! Makes me think I need to stay with my 4 wheeler and let this bike be under someone much younger than me, or a least someone with more *****! Thanks a bunch to all the people that responded to my request for help.

 

Glad to hear you got it running. You'll get used to the speed quickly.

 

Good to hear its running smooth. May I ask what Seafoam is? Is this something that you add to the gas tank?

 

Fuel additive originally used in the marine industry. IMO its great stuff but results vary.