I know getting an actual diagnosis over a thread isn't going to happen but looking for ideas till I can look at it or get it looked at.

Rode to work last night as usual and ran fine all the way there, about a 30 min all hwy ride on my 02 f4i. I got to the stop sign before the employee lot and when I pulled the clutch to stop it just died. It turned over fine but wouldn't start till I gave it some throttle and now it seems it's at least got one cylinder not firing. It wouldn't idle w/o me giving a little throttle and I smell unspent gas. It rode into the lot just fine just vibrating a lot and loud, seems like it might be the compression of the non-firing cylinder I'm hearing from the engine.

I believe it's been about 2 years since the last valve adjustment and I keep up with oil changes etc. I don't know about the plugs being changed, I've owned it a year and a half about and haven't changed them.

Any chance this is simply a fouled plug? I thought maybe it jumped timing, previous owner had the CCT replaced as f4i's are known for the stock CCT rattling I guess, but I'm not sure it would run as well as it did if it jumped time as then all cylinders would be out of time, right?

Any thoughts would be great on this! Timing really sucks as I was riding as much to save on gas as to be riding at the moment since I'm pretty f'n broke at the moment. So IDK when I'll be able to afford to have it properly looked at. So I thought if the chances were decent of a fouled plug being the culprit I could do that here myself and save money but if that's not very likely I'll just wait prob. Never rode or heard a bike with a fouled plug so IDK.

Also, does an f4i have an interference engine? I'm betting yes but can't find a definite answer online yet.

 

Oh, and no lights are on on the cluster, no FI light or anything like that. Everything works fine other than being down at least one cylinder firing.

I was thinking, I'm going to tear into her tonight or tomorrow and check out the plugs and be sure one hasn't simply backed out or something, but before I tear it apart, what's a good way to see what cylinder isn't firing? Also any possibility of a coil pack being bad causing this? I had no choice but to ride it very slowly home, in the rain no less damn it!, and kept the RPM's down but it didn't seem to have any problem pulling at all.

I'm really hoping it's something simple but am not having any luck finding any problems even similar and have searched on google and through over 50 pgs of posts here so am becoming increasingly concerned!

 

Check the terminals on the battery. Loose connections or a low battery will cause something like this, especially suddenly out of the blue

 

Ok, so I just checked the exhaust manifold while idling and it seems all 4 are firing after all. I've found a lot of info saying the FPR is a very common problem that can cause you to smell gas and running extremely rough, so I think this may just be my problem. The only thing that I'm not sure of is that it is VERY loud! It almost sounds like when whatever happened happened it blew out the exhaust manifold gasket or something. Does that make any sense?

 

I ordered a new FPR online yesterday and just now found this video and his bike sounds EXACTLY like mine at the moment. I'm gonna check the plugs probably later today when I find my damaged screw removers, slipped on a tight screw holding the lower part of the air box down. FPR is on its way already and I was gonna at least check the plugs while it was apart but now hearing what mine sounds like does it still sound like only the FPR?

‪2003 Honda CBR600 F4i - Blown Spark Plug‬‏ - YouTube

 

So, I got the new FPR a few days ago and put it on with no change in how it ran but I didn't really expect it to as I hadn't changed the plugs and figured at least one was fouled from running so rich. I had drill with the Army this weekend so couldn't change the plugs till last night. So I was pulling the old ones as my wife picked up the new on her way home, don't worry I called ahead and had the parts store have the right ones waiting on her! lol. I started on the brake side and when I got to the third one (center clutch side) labeled them as I went to not mix up the order, I turned the boot to loosen it before pulling it and it sounded like the plug was turning with it. When I began to unscrew it, it only took about 1/4 turn and it was free! So I tightened it down and replaced the others just to see if that was the whole prob all along and it was! Ran fine with old, and VERY carbonized, plugs! So I'm not sure I needed the FPR at all. Can't hurt I figure and the plugs needed changed anyway and this just made me do it. My question is, does this ever happen?! I didn't put the plugs in so I don't know if they were tightened when installed but could they just have not put them in tight enough and it worked itself out that far?! I'm broke at the moment so put in NGK's still but non iridium so they'll have to be at least checked on more frequently but I figure that's not a bad thing so I can see what's going on inside the cylinders and be sure none are pulling out on me again.

Now I'm going to be doing the airbox mod. and finding a new map for the powercommander I forgot was on it when I bought it! He said he just had stock maps on it and hadn't changed anything yet so I gotta find one similar to my set-up for now till I can afford a dyno tune like it needs. It already feels better with new plugs on the short ride I took after getting her together last night so all these little extras will be cool to have!!

 

I just bought iridium plugs for my bike 2000 929rr and they were only like $38 for all 4. The recommend DENSO IUH27D in the manual but i did my own cross reference and got NGK CR9EHIX-9. Just type in (google) "spark plug cross reference Denso NGK." ***Remember mine is a 2000 929RR not a F4i like yours***

The Honda/Slutzuki/Yang-Bang Stealership wanted $25 for the NGK, and $33 for the Denso. Get the numbers, call ADVANCED AUTO PARTS, best prices I could find. That is for your budget issues. Send me a PM if you get confused, I think I still have the webpage bookmarked and I will help look them up for you if you want.

About if this happens.....My #1 plug just fouled out less than a month ago and demolished the Iridium tip. The other 3 plugs looked horrible also, my plugs weren't loose but yes this does happen. IMO I would get the Iridiums in there as soon as I could, just my opinion.

Hope some of this helps.... and congrats on the getting her running right...