I recently picked up an 04 KFX 700. The previous owner put a pro circuit dual exhaust on it and I just put a UNI filter in. Everything else including the jetting is stock. Any suggestions on a starting point for jetting?
Elevation looks to be about 700'... about the same as me.
You probably won't have to change much. The stock jets are 135F/140R. You may have to go to somewhere in the range of 140F/142R to 145F/148R. I think if you picked up actual Keihin jets in the 142, 145, and 148 sizes you would be good to go. This is all assuming that you haven't done the 12-hole airbox lid modification yet. If you have done that already or are planning to, that changes everything and you will need much larger jets.
Wow! Seems like only yesterday I was asking these exact same questions. :lol:
I guess you guys need more info. After I added the filter i started running rough. At idle it was sputtering then when you gave it some gas it would slowly build rpm's then it would all of a sudden seem like it was cleared out and run fine until you let off the throttle.
For shits I took the carbs apart. I found a lot of junk in the float cover gasket. Other than that they were fairly clean. The jets were labeled 120 in the front and 124 in the rear. Both pilots were 40's. Now that is different that someone said stock should be. The previous and only other owner said he never messed with it. After I took the carbs appart I pulled the plugs. They were black. That leads me to beleave that it is running rich which is backward from how it should be since it is getting more air. I added some pics of the plugs and gasket to my profile if that helps. I am stumped.
Are you sure those are Keihin jets? The numbers should be on the sides (not on the end) and have a "K" symbol next to them. I am wondering if, at one time or another, someone put Dynojet jets in it. Those would probably be a number like you are talking about.
Another though is that you have an over-oiled air filter. I had a similar issue and found out that I used too much filter oil. I cleaned & re-oiled the filter and everything was fine. If it is over-oiled, the motor will have a hard time drawing in air at low rpms but isn't as much of a problem at higher rpms... other than loss of some power. That would also explain why it seems that you are running rich. It can't get enough air into the motor. Just a thought.
Thanks for the help Twyztid. The jets are marked on the ends. They must not be factory. The air filter is one that I had to oil. I used quite a bit of oil. I thought more was better...guess not. I am going to get new plugs and gaskets for the carbs. After I get that and reassemble I will start it up without the air filter in it and see if thats the problem. Again thanks for the help.