Hi all, long time lurker, one of my first posts.

Unfortunately two days ago I fired up my f4i and it sounded and felt terrible. I took it halfway down the street and it had about a 10th of the power it usually does. The night before it was working just fine.

So far I've checked the spark plugs, ignition coils and CCT with no luck. Made sure all the connections and tubes are together. There's no code when turning it on. I'm a little reticent to open the engine head to check the timing but I imagine I'll have to.

Here's a video of the sound it's making and a bit of the acceleration sound.
Just looking for some suggestions or idea what it might be.

 

Sounds like there is a vacuum line off. Pretty big one too.

 

Thanks for the quick reply.
I just rechecked all the hoses and everything is connected, unless there's an obstruction in one somewhere.

 

yeah, feel for air flow around the bike and try to put an ear on where the massive amount of air is coming from, check the exhaust too so you can rule out if its a leak and the problem lies further than what we hear.

 

I also did not secure the airbox so that's probably one of the things you're hearing.

 

can you verify the fuel pump, when it primes, sounds the same as it normally does? does the exhaust smell the same?
when you say it runs worse does it sound and run worse when not under power and you just rev it?
we're hearing something in the video which is not normal at all so maybe lay the tank back down and put a few screws in the airbox.
the engine shouldn't of developed any problems overnight but electronics and other things can.
were the plugs wet? i would check out the fuel pressure regulator and make sure the battery is good and charged. also keep an eye out for any FI codes
you have 5 hoses plugged into the bottom of the airbox and 2 electrical lines right (1 on top and one on the bottom left)?

 

Fuel pump does sound normal when priming. The exhaust smells a lot richer so it could be getting too much gas. It sounds worse when it's idling and revving but much more noticeable when it gets to about 4k RPM.
Plugs all have good spark, no FI codes. Layed the tank back down and took another vid. Not good quality so I can rerecord it if it helps. I'll probably be taking it to a shop soon as I don't have some of the tools I need to check for certain problems.

 

did you do anything to the bike? check your throttle body, it sounds like the adjusters on your throttle body is opened more then then needed, also i would check your spark plugs again for spark, and made sure they are properly screwed in. It does sounds a little like one of your cylinders aren't working, my bike made similar sound when one of mine spark plugs stopped working. that would explain the loose of power. or did you heard any clicks right before you loose power? maybe your timing chain got loose.

 

yeah, something isnt running right. have you done a test on your fuel pressure regulator?
it could be drowning one of your cylinders

 

Thread can be closed out.
Took it to the mechanic, turns out the intake valves were .03-.04 and service limit is .07-.09
He adjusted the valves and it's better than ever, in case it helps anyone else. The reason he suspected this is because it was running 43k miles and the last valve check was pre 30k, before i had it.
Thanks all.