I have rejetted my Lakota with a stage one kit. I also added a IDS2 Supertrapp exhaust along with a K&N filter. I am around 700' above sea level so I used the 138 jet, largest that came with the kit. I am running 8 disks in the pipe and started with my needle on the #3 groove. I felt it was running a bit rich so I lowered it one notch, to #2. Now it seems to be running too lean and doens't have near the power it had before I lowered the needle. I also noticed that the original jet was a 140. Is this a larger jet than the largest jet that comes with the stage 1? Should I leave the needle where it is and use the original jet? Can I put the needle back to #3 position, leave the jet alone and try to adjust it out with the fuel mixture screw?

Thanks for your help!

 

First of all,. you need to determine where in the band you feel you're lean before altering anything. If you've dropped the needle from the 3rd position then it's in the 4th position not the 2nd. Positions are numbered from the top. Many of the jet kits use proprietary numbers which don't necessarily jibe with Keihin, Mikuni, or whatever. The commonly accepted method of jetting is to start with the Main jet by doing a 1/2 mile or so test run/plug read at 3/4 to full throttle (any gear you like). Stop where you are & read the plug for proper color. Tan or brown is the operative word. If the electrode is gray or white, your lean condition is in the main jet.
I would think you need to run your main at least two sizes fatter than the stock 140. It may be simpler to just get those from your Kawi dealer if you can't correlate the sizes with the jet kit ones.
After the main jetting is dialed in, then you could test again for the needle jet at 1/4 to 3/4 throttle, again for 1/2 to a mile & read the plug.
Of course you should return the needle to the nominal position before doing any of this testing. You're basically at sea level (under 1200'), so the needle will probably not need any change.

 

I have rejetted my Lakota many times and have experiments with many sized jetts. Unfortunatly I can't help you because California Lakotas are jetted differently than the rest of the states. It's because of our strict emmissions standards.
Stock Lakota jet in CA is 148.

 

sorry to be so confusing. I realize that position start from the top down. I lowered the needle by changing the slot to #2. To get a reading on the plug I have run the bike around for about 15 min then pull the plug. Not necessarily for straight line at 3/4 to full throttle. So you think this is what I should be doing instead? Thanks for your info.

 

OK,Since I'm not sure what your stock jet would be in your area I would contact a local dealer & find out what they install as stock . Then I would pick up the next two sizes fatter. Then replace your needle to the 3rd position. In testing for a correct air/fuel mix on the main jet it is necessary to use a new plug and ride the bike at 3/4 to full throttle, not necessarily in a straight line, but at the rpms mentioned, because that is where the main jet operates.If you test at lower throttle or just putt around after testing, then you're going to get a reading from a different jet circuit & not really learning where you are lean, rich, or whatever. As I said in the first reply, don't worry about being in top gear..just pick any gear; your engine won't know what gear you're in, it only knows 3/4 to full throttle for a mile.

 

OK, I have returned my needle to the #3 slot and left the 138 main in place. I figure the stage one jet kit should come with jets that I need, I certainly see what you are saying though. The bike seems to run well. No hesitation or stumbles anywhere in the rmp range. However, the spark plug is mostly black, not horribly though. The porcelin in the center has the tannish brown color though. I think it is a little rich but overly so. What do you think?

 

If the insulator is tan or brown it would appear to be jetted correctly as that's where the heat is most intense. If the engine was getting a lean mixture, it would likely show up there first. Also, the performance sounds like everything is on the money.