Ok, the all stock ( 07 klx 250s) is reported to run lean from the factory.Idon't knowtoo muchabout carburation, but if I'm thinking straight the bike should run richer as you go up in elevation. ? Less Oxygen to burn, but the same amount of fuel.
I ask because I'm here in IL. (EL 750ft), and plan to be ridingmy KlX in,and around Rocky Mt. Natl. Park this summer. (EL 8000-11000 ft). What do you think? Will that swing the stock jetting to too rich? Most of my riding would be closer to the 8000 ft altitude, on forrest acess roads around the area, but I'm thinking I might take a trip up Fall River rd.in the park,which peaks out at nearly 12000 ft. My bike is still all stock. I'd like to be prepared when I get there, which I'm thinking means taking some extra jets with incase the bike doesnt want to run right at that altitude.
Also a question for anybody familiar with the Colorado forest access roads, and OHV trails. Probabbly not on theforrest acess, but do I need a tag or permit for the OHV trails even though my bike is licsened?
Thanks Dan

 

Here is a suggestion. I did this when I was going to nc. I went to the dealer and if ur bike is stock this is a good idea since mine was stock when I first took mine up north. I am in florida and the stock jet size is 118 the size I used for the mountains up there was a 115 I now run a 125 with a pipe and It runs fine here and there. Also there is a pilot jet for high elevation. Change those 2 when u go up to there. The only way to really know is seat of pants and trial and error. If it pops its too lean. If its smoking black and leaving a sout trail on the fender its usually too rich.

 

Dan,

I would say that the answer to your question is, probably not.

I live at 5300ft and ride to 11,000ft in northern NM. In stock form, the bike would not run at 8,000ft and above. You can experiment with different jets and airbox lid combinations, if you have the time and the desire. A 115 main is a good choice to have along. I had decent luck with a 122 main, but that was with an aftermarket exhaust, K&N filter,and the KDX snorkle. You could try the stock 118 main and remove the airbox lid entirely, that worked somewhat too. Pull the plug covering the mixture screw, you will probably need access to that too.

A stock KLX is no mountain goat.

Good luck,

Tom

 

Hey tom did u forget to tell him where and how to do that? Hes a new member perhaps he hasnt read about the carb mods yet.... Ok here ya go buddy. First thing u will need to do is shut the fuel off with the bike running and run all the gas out. Pull the fuel line off the carburetor and remove the seat followed by the fuel tank. I found that removing the right radiator shroud is a good advantage to getting to things on the carburetor as well. Ok now after u have the fuel tank off U will need to remove the smog hoses the go over the top of the carb followed by removing the throttle cables but remember where they were for when u reinstall them. Remove the hose from the bowl over flow right next to the throttle cables. Take lose the two boots and I found out that losening the airbox side inlet boot for the carb was helpful as well. Once I get some pics off my camera onto the pc I will post them.

 

Thanks Tom and "Monkey boy". Thats pretty much what I thought. I'll have to dig around on here and figure out how to get the correct 115 jet, and do some more searching here on the board to learn more about how the carbs work.

 

You could also try pulling out the stock airbox snorkel and just run with the air box lid on. I did this once running at 4000-5000 ft altitude and it worked very well. If not try pulling the airbox lid altogether.

 

The stock carb will not run very good above 8,000'. Jo Ann & I go to Colorado 3 or 4 times a year; we have taken several bikes out there & the CV carb bikeswillnot run good above 8'000'. You can help the way they run by removing the air box lid & jetting the main jet 12% leaner; this always helps the way they run. We have ridden our bikes up to 14,000' butthey really don't like to run at that altitude. SinceI put the TM33/34 carb on our KLX 250/300, the 12% rule works for us, airboxlid on, KDX 200 snorkel.

 

When I first purchased my 07 KLX I rode it (100% stock) up and over Butterfield Canyon (Utah) where the elevation is over 8,500ft.
At about the 7,000ft mark the bike started to have difficulty with a noticable drop in power, by 8,000ft the bike would only keep running if I kept the RPM's over 5,000 and I barely made it over the summit.
At the same time the bike ran well in the valley (4,400ft).


The following weekend I replaced the snorkel with the KDX version and installed a Uni air filter (only mods) and the bike ran perfectly over the top after that and higher (10,000ft over Guardsman pass).

 

+1! I've also ridden my bike (oem jets) in northern Arizona - 7,000' to 8,500' before I changed the jets to the elevation where I usually ride (2500'). Adding the Uni air filter plus removing the air box lid and the KLX ran fine!

 

I have a 95 KLX 250 and I have to say I think it does fine at higher elevation with the stock jets. Though the bike may be jetted as I didnt buy it brand new. Who really knows??My mods are gears, and the removal of the top of the airbox that I know of. The bike carried me and my wife up over many passesin the Colorado area. Probably 320ish lbs of load. I wouldnt say that I was flying up the hills, but I did just as good or betteras the guys with bigger bikes. I think the smaller lighter bike helps when the trail is narrow, slick,rocky ect. I think either way you need to keep the revs up cause the bike will tend to load upin higher elevation anyways.It will also loose quite a bit of power but it is stillenough power to get you up the hills.

We have only beenchecked once(in Colorado)for tags and my bike is-was licsenedand I had no issue. I think you will be fine though I know that is not an official green light.

Good luck!
Kyle