My bike sometimes start, but most of the time it doesnt. When it does start, it idles fine, but when I reeve it, the rpm goes up, and then it drops and the bike dies. After a few cranks, the FI light will point to the IAT sensor, which I've tested and it's fine.

I've taken the fuel rails + injectors out to test for gas, and there is. when i crank the engine, each injector will give a small burst of gas which I can't see, but I can feel with my finger.

 

i think it's the fuel pressure regulator. when it manages to start, it also reeks of gas.

 

Sounds like you are on the right track, a lot of your symptoms are listed here https://cbrforum.com/forum/f4i-main-...gulator-82635/.

 

grr. replaced the fuel pressure reg today..and no go. now i smell of gas, and I am down $70. I'm going to pull the fuel pump to tomorrow and check the fuel filter for blockages.

Are the $50-70 new fuel pumps on ebay any good?

 

Eh used fuel pumps are a bit of a gamble. I think the f4i fuel pump was somewhat of a common problem, so buying a used one might mean youre gonna be buying another one in a few months again. If you get a good one though you made out pretty good, just a risk you have to decide on.

If you think its the pump then buying a used one for cheap and seeing if it solves the problem isnt a terrible idea though. If it works then you can ride it till it goes on you, if it doesnt fix the problem you can just try to resell it for whatever you paid and start from square one again. Would a bad fuel pump explain the smell of gas though?

 

Have you pull the plugs and see if you can diagnosed problem? Idle fine.....then rev up & dies....something is not balance...air/spark/fuel...anything too much or too little will kill engine.

Pull plugs and see what it look like?

 

i've check the plugs. but i'll check each one again for spark.

 

no. i'll be getting a new pump, if i get one. ebay has aftermarket ones for $50-70. Just seeing if anyone else tried them.

 

RAWR!!!!! finally fixed!! not the pump, filter, ecm..etc. all it was was a bad ground. a wire to the Electrical Pulse..thingy...from the clutch box had somehow busted open and was covered in dirty. After some soldering and a piece of electrical tape... Baaaam! Bike is up and running like a beast. man. electrical shorts suck.

long story: after pulling out the fuel pump and filter.... everything appeared to be in order. I blew and sucked air through every hole i could find... and the filter and the pump flow-ways were beautiful. So put everything together again.... pull out the fuel rails and injectors.... to see if it was still dropping fuel. I crank the starter.. nothing. there was pressure, but the injectors were not shooting.

Out of fatigue and frustration, my fingers slipped and the rubber washer/gasket from the far right injector fell into the bike. With a flash light, i dug around... searching for the rubber ring.... and that's when I came across the funny looking wire. Although it was mostly covered by the dirt and grim, the flashlight lit up its traces of a copper color. I ran my fingers across the suspicious wire, and sure enough, its broken edges poked me. The wire seems to have been rubbing up against the hot engine and overtime, it has torn through.

man. i'm exhausted. my back aches. and my mouth taste of gas... haha. but the F4i has finally came back to life. Now, it just needs a valve job and a new front tire. Shoot, if it behaves itself, i'll get it one of those steering dampeners.

 

i had something like that happen to me, did you check all of your hoses going to air box?