My first post on this or any thread! I've been reading and taking some of your advice on mods for my bike. Thanks guys this site is super helpful! I have an 06' with a 13t and a FMF Q4 full exhaust, and was wondering what I should do if anything to jet the carb? I have a K&N, but the airbox is stock. I'd like to open it up a bit any suggestions? The exhaust helps but like anyone else I'm looking for a bit more.

 

welcome!!! did you do a search for carb mods here on the forum? the easiest thing to do is go buy a jet kit(i did the dynojet jetkit for the klx300). you could just go geta main jet(125 or128)and that needle everyone talks about. i forget the designation for it but it's in here somewhere. by the way you HAVE to rejet the carb. you have a lot more air running thru there and need more fuel to get the power insrease you looking for.

 

Still stock jetting? Not letting the pipe do much good. The "standard" is chuck the snorkel or the entire lid all together. Stock pilot, 2.5 turns on fuel screw, NT1C needle on second groove, enlarge slide vent hole to 7/64ths (or DJ uses #32 if I remember--its bigger I know that). From there eveyone has experimented slightly up down on main size, needle position, lid vs no lid, or bumping the pilot one up. Its where your mileage may vary depending on setup & elevation.

Can also run a KLX300 DJkit. I dont have experience with the DJ kit at 250cc so I can't comment. I ran the above setup with no lid at all @ 1000 ft @ 250cc. But the DJ setup I have now is crisper. Is all in the needle.

 

What Dynojet kit did you use? They don't have one specific for the KLX250. I'm a bit lost here.

 

The KLX300 kit works but I am running KLX300 displacement also so it was a slam dunk for me. 250ccrequires some reasearch--many have done it here, I just can't quote the numbers they came up with off the top of my head.

 

I'm using the KLX300 DynoJet kit with the 128 main and the needle on the 3rd clip position ...My elevation is about 600ft. to 2000 feet of use.My pilot is a stock jet and the needle is out 3 1/2 turns or so....The #40 pilot is too much and the #25 is way to small....I'm running with no airbox lid at all and a twin air filter.Also using a 4 Stroke works header and an FMF powercore IV silencer.I'm currently using a #30 pilot jet....Stock displacement.Bike runs like an animal.Pulls hard from idle to about 8700 rpm..after that it drops off hard....I know it's not jetting related but it's an airflow issue or cams....if you read most posts about cams and carbs and bore size it always comes back to the issue i have.......I already have my next steps planned.

 

Thanks for that Truckman...I'll be looking into the KLX300 Dynojet. How safe is it to ride without an airbox lid? What about water and crap? I livde in Northcentral PA and some of the trails I ride have a bit of water to cross which is cool...or is it?

 

Hey Js, I didn't even see you sneak on here. Welcome man.

 

i have my lid on but no snorkel in it.....

 

I ride the Ashland/Centrailia area all the time in NC PA....(maybe NC) and i've never gotten water in the airbox....I also removed the drain plug as well...I also rode the H-M trails in west virginia with the same setup and not a problem at all and there was some deep water crossings there as well.I have seen some mud spatters on the underside of the seat but that is about it....You'll be fine unless you really go dunking her,,,which i really doubt if you ride that area.