Hi everyone,

I've read a few threads here to try to figure out what my problem is, but none of them answered what I'm looking for...I have a 2002 600 F4i here's my problem:

Recently, perhaps the last month or two, I've started to experience a LOT of jerkiness and up-and-down RPMs between 0-4000rpms, generally between first and fourth gear, after the bike has been warmed up (I don't experience it when I first start it up). I've read other threads where people say that it's human error and that I'm revving the throttle, but I promise, my throttle is steady. I get the biggest problem when, perhaps, in traffic and I'm going about 30mph in 3rd gear at about 3000rpms. I'm on the throttle to the point of trying to maintain a consistent speed (so, not much, obviously) and the RPMs start to fly back and forth in the range of about 500rpms, and the bike feels like its jerking forward then not, then jerking, then not again. Similar experience with first and second gear at lower speeds/RPMs.

I do not experience the jerkiness above 4th gear, generally because I'm going faster than 40mph and higher than 4000rpms.

I say that this "might" be a fuel injection problem, because as I was riding home from work this afternoon, RIGHT before I turned off my bike I noted my FI light was on, but I had turned the bike off right after noticing it and haven't turned it on since then.

Anyway, help would be appreciated. Please let me know your thoughts.

 

how many miles on the bike?

How old is the fuel in the tank?

Any rust or dirt in tank?

How old is the air filter?

How old are the spark plugs?

 

Appreciate you taking a look.

 

Perhaps I'm just riding at too low of a speed/rpms when I'm in too high of a gear? I tried that today while riding and didn't notice it as much, though I did still notice some hesitation/jerkiness when accelerating slowly in first gear...

 

Shine a flashlight inside the fuel tank, see if there is any rust inside.
If rust clog up you fuel filter or worse fuel injectors, your engine would surge while throttle held constant.
If air filter or spark plugs have never been replaced in 22k mi., they are due for replacement.
Dirty air filter / spark plugs can both cause surging.

 

How tight is your chain? I would imagine if the chain would be too tight it could cause a jerking motion

 

Thanks, I don't think the chain is too tight, the dude at the bike shop around here mentioned the chain actually might a little loose...he said it was fine, but could use a little tightening...so probably not that.

 

Also - I really only notice the surging after the bike has been warmed up...when I'm taking my bike out of my garage, through my apartment complex, there are no problems, but when the bike is at normal running temperature (175-225)...that's when I get the problems. Just wanted to pass that on also.

 

Check your vacuum hoses , map sensor , fuel pressure regulator , and of course if the tank has debris floating around. Pretty sure it's one of those simple things. I say this because I was having issue of random idle and rpm surges. It came to be a bad map sensor causing a bad fuel air ratio mix.

 

Since you stated your fi light came on, it is likely there is a code stored from that event. There is a self check procedure that will allow you to retrieve a (blink) code from your bike in reference to the failure. You will only need a short piece of small wire, or paper clip, 10mm to remove seat, piece of paper and pencil (to write down the number and sequence of blinks.) Remove the seat , make sure the key is off, install a jumper in the service check connector near the battery (a two terminal female plug that is not connected to anything). turn the red stop switch to on then turn the key on and watch the FI light. If there are codes in the ecu memory, the fi light will flash. DO NOT remove the jumper wire while the key is on, or it will erase the codes. (at least until you figure out what is going on.)

Now the maximum number of blinks is 33.. so a single blink = half a second on then off.. once it gets to a code with ten or higher, here is how it works. 1.3 second long blink = 10 so if you have a 1.3 second blink then a .5 second blink that would = 11. if you have two 1.3 second blinks that would = 20 and so on. If there is more than one code, it will blink them out in succession. so count the blinks and let me know, i'll help if i can.