Glad to see some fellow pineys on the forum - I'm new to the forum and just bought a stock 2006 klx 250 last week. I'm loving the bike compared to my dr200, but want to get a little more performance out of it without spending too much right now. I'm going to be putting on a 13 tooth front sprocket that I ordered tomorrow, and I'm thinking about the common mod of removing the airbox snorkel and drilling the 1st muffler baffel to 1/2" - anyone have any experience with this particular airbox/muffler mod? I'm wondering how much louder it will be and if I should plan on adjusting the carb afterward. Any advice would be great!

 

Congrats on the bike!
I would suggest upping the jetting. The bikes come lean from the factory, and pulling the snorkel will make it a tad leaner.
Dan

 

I did the 1/2" hole with no jetting change and it was ok, very small change in power, only a slight improvment with very little change in exhaust noise. I'd jet at the time you pull the snorkle as that will require it to run well. The Dyno jet kit 2152, that's for the 09 bike and yours may be different. I believe the instructions for this change are on their web site they are there to read for free on line. I'd go with the DJ kit as it will have more jets if you do more mods and I'll tell you from experience the aftermarket pipe on the stock bike made the best improvment of all the things I've done so far.

 

Thanks for the advice, guys. I checked with Dyno Jet and they do not make a kit for the 06 KLX250 yet, so I'll have to go with the non-kit jets. There is a thread on ADVrider where the following is recommended if you are doing the 1/2" hole drill in the stock exhaust:

high flow airbox snorkel
N1TC needle 2 slots from the top
#125 main jet
drill the slide vent hole to 7/64"
uncap the pilot screw and turn out 2.5 turns

Looks like that could all be done for around $75 - what do you think, Dan888? Looks similar to some of the mods you've done.

 

The DJ kit for the 300 works great with the '06/'07 KLX250. The DJ needle is superior to the OEM 300 needle, and this is where the kit is worth it IMO.

 

Yep, you have to order the klx300 jet kit.

Actually, there are two jet kits that will work. 2152 and the 2206.

I recommend the 2206 kit.

 

I went with the 2206 kit for the 300 in my 2010 250s, and also removed the snorkle, drilled 1/2 hole in first baffle, drilled the slide and went with the 13t front sprocket. Made a big difference from how it was stock. the only prob is I can't up the notches on my main needle till I get a aftermarket slip on. Can't get the exhaust out quick enough with the ****ty factory muffler.

 

Nice - I took a look at that 2206 kit - any thoughts on which jet would be best to start with using the high flow snorkel and the 1/2" hole in the first exhaust baffle. In the pinebarrens, there's no chance of me going over 180 ft above sea level Any advice on removing the countershaft nut to change the front sprocket? That damn thing is ON there. On boats around here we use a torch to heat stubborn nuts that the salt water welds to the bolt, but I don't want to do that here with the plastic washer under the bent one.

 

When I did mine I just checked around with people on here that were around my elevation(sea level) and went with what they were running. Which ended up being 125 main and 38 pilot. Worked good right away. have to mess with the air screw a bit. But maybe someone with you elevation will chime in and let ya know. As for the nut I used a electric impact gun and it came right off. Not sure if this is a good idea or not but it worked for me. Mine was also right off the showroom floor so prob. a bdit easier to loosen.

 

Hold the sprocket with the rear brake, not the transmission if you are going to use an impact.

I drilled the first 1/2" hole in the muffler, then a 5/16' or 3/8"" hole in the next baffle with a long bit (the biggest one I had). Its a little louder. It sounds like the airbox is louder. It seems to really come on to it around 6.000 rpm. It gets louder and seems peppier.

We have rain and in the thirtys here. I have seen snow. The season is over here.

David