I realize that there are many, many posts and threads about this topic but I just need some specific to my situation typeinformation. I live in SLC, UT (about 4500 ft) and I will be riding my 07 KLX 250 to work about 20 miles each way with mostly highway riding in some dicey traffic ( aka I need to go real fast sometimes) with the occassional dirt ride. I have the Big Gun on it's way and I have already ordered all my parts for the carb rejetting. I just want to know what will be best for the jet, needle, notch, and airbox modifications. I am going to stick with my stock gearing for now and see how it feels and change as needed. I will end up changing out the vortex core for the quiet core with the exhaust, but wasn't sure if there was anything else with the kit that I ordered from Big Gun that could be improved like the header or what not, and no deej that doesn't include swappig the whole thing out for a Muzzy. I have posted a question like this before but it turned into a preach fest about riding behind semi's so if anyone wants to respond thenhelp mestay ontrack, I am a super newbie depending on ya'all for some good recommendations to refer to in the near modification future. Thanks Dacoontz.

 

Seems we easily get distracted in this Forum - most of us have A.D.D. in here!

I ride between 2500' and 4000' in the high and dry Sonoran desert and using the mods below work pretty good for me, but you are going to find that everyone has had mixed results with jetting. You might have to play the "rejetting" game a couple of times before your bike and at your elevation runs the way you want it to. Good luck and have fun!

HMF slip-on with #125 main, #36 pilot (oem jets), NITC needle slot 2, F/S 2 turns, drilled slide vent 7/64", smog removed, NGK Iridium plug, KDX snorkel with UNI air filter, 13T front sprocket, Dunlop D606 - 120/90-18. I have noticed that it does run better at higher elevations with the open air box vs. the snorkel.

Hope this helps!

 

I live at 5300ft. I don't remember all the combinations that I tried, but I ended up with the stock pilot jet, a 122 main, and the KDX snorkle. I was using the N1TC needle on the second clip. I ended up with the mixture screw at about 1 and a half turns out. I tried lots of combinations with jets, clip position,and the mixture screw, but all that got me was more fuel used with no apparent increase in power. Unfortunately, I didn't try any other airbox lid/no lid combinations. I don't know what difference a drop in only 800 feet from me will do, but I currently have the bike nearer to sea level in the Portland, Oregon area, and it's like a different bike. When I'm at home in New Mexico, I can usually be found somewhere between 5000 and 11000 feet. It was a little frustrating getting it to run at altitude, and I never was really satisfied.

Get an assortment of jets and be prepared to experiment. Pulling the carb gets easy after the first couple of times.

Good luck.

 

klxrider, what kind of riding are you doing mostly? Do you think changing that front sprocket is as good an idea when i am going to be reving high on the interstate? And I figured I would just remove the snorkel and leave the airbox as is. Thanks for the responses. Dacoontz.

 

And warski, may be I will just grow some and try to do the mods by myself. I was going to pay someone because I am truly new to this stuff and didn't want to screw with my first bike. Did you have to remove your gas tank to do the re-jetting or is it do-able without touching the tank. Dacoontz.

 

you have to remove the tank but that is really easy.take off the seat (2 bolts) remove both radiator shrouds (3 bolts per side) and remove the tank (3 bolts on tank) make sure you close the petcock for the fuel and remove the 2 little bolts that hold the petcock to the frame.Then drain your carb into a suitable container.next remove the fuel line from the carb....now you have full access to remove the carb.The biggest PITA is the stupid bracket that holds the throttle cable to the carb body, it can be a real bitch to fanagle sometimes but other than that it's really only a 20 minute job to pull the carb.....I think the first time i did it it took me an hour but it's now quite easy to do after i've done it a few times.

 

Pulling the tank is easy, just as truckman said. I do recommend that you have a nearly empty tank when you start, it makes it easier to handle.

I took a dremel (cutoff wheel) to the bracket that holds the throttle cable and cut off the small tab that makes it so difficult to re-attach. Now it's a simple job to place it over the alignment pin, rotate it into position and secure it with the single screw.

If you can work a wrench and a screwdriver, you can do the carb yourself. Be careful with the floats and the diaphram.

Everything you need to know, with pictures, is readily available.

Good luck.

 

Since I have the Dunlop D606 in a 120/90 which is a tall tire, the 13T sprocket feels more like a 13.5T. The bike is more responsive with the 13T (higher revs - quicker). I can still easily get it up to 75-85mph but don't like to since that means washing my underwear more often!

 

I live in South Jordan, UT (SLC Suburb).
I experimented with dozens of different set-up's, I tried the N1TC needle clip on every possiton and wound up using a .034" spacer washer under the stock needle which has a more linear power delivery; (anyone need a cheap N1TC needle, clip, spacer?)

I tried the Kouba FS-3 screw and couldn't get the idle stable no matter what setting, I have the stock screw set at 2 turns out.

I ran with the stock 118 main jet for a while but it was lean, then switched to the 125 which ran better but showed signs of being rich and my milage went to heck, I have a 122 main jet in now and it is perfect at this altitude.

I run an FMF Q4 Pipe and header, Uni Air Filter, KDX Snorkel, I've done the crankcase/airbox vent mod, drilled the carb slide and removed the KCAS system, I also use an NGK Iridium spark plug.

I'd be more than happy to help you do your mod's if you want to bring your bike over one day, I have a heated garage and the tools required. PM me.

Dave

 

For the newbie mechanic. Here are a couple of general tips that will avoid frutration upon re-assembly.....
As my ma said when I was a newbie "Ronnie, you always take things apart, but hardly ever put them back together "


1. these bikes are metric.... use the right tools.
1.5 prep your area for the project. Nothing worse than tripping over crap that does not help the project.
2. Take pictures before disassembly. Its good to get close shots from different angles for complicated piece assemblies.
3. cups and markers. I use plastic disposable cups for holding smaller parts. Label and group them that makes sense "airbox", "carb"....etc. Use boxes for bigger parts.
4. puts screws back. I usually put the screw back in the welded nut or where it came from. loosely screw them in place . That way I know were it is.
5. look at all angles. getting the carb out takes some "puzzle fitting" to get it in and out of position.
6. take a break. When things go bad, its time to think about something else for a while. I get excited to get things done, so this one is hard for me. but it helps avoid making more mistakes. getting back to it with a fresh mind is always best.

Here are a couple projects I have done:
http://www.picasaweb.com/rbarchi