Recently bought a '09 KLX250s and doing the typical mods: slip-on, Dynojet, K&N, etc. Did the re-jet, but now the bike has a little bit of a bog up to 4500-5000 rpm. It does great above 5k, thinking it's too rich up until that point? Followed the DJ instructions. When it comes to carbs I am a complete newbie as far as tuning or troubleshooting. Recommendations for what to change to clear it up? thx!

Ryan

 

Yes, at that rpm range the needle has everything to do with mixture. If its running rich you need to move the needle E clip up a notch, possibly two. This moves the needle further down into the main jet letting less fuel out to be atomized. Go with one notch if the bog is not too bad.

 

Did you take out the snorkel yet? You might try getting more air in there first before you go back into the carb. It's most likely the needle like he said but if it's a small bog more air just might do it.

 

Yep, snorkel is out. Wanted to try it before I yanked that carb back out. With the snorkel in, it changes to having some surging probs while at a constant RPM. I will work with the needle a bit and see if that will fix it. Thanks!

Ryan

 

I would think you dont need to yank the carb all the way out for the needle? just get to the 4 screws on top to pull the cap and you should be able to do the needle adjustment and leave most everything carb wise still connected.

 

Yeah, I can probably do it that way. Will just have to make sure the needle gets in the seat properly.

Ryan

 

If you can manage to have the slide down and drop the needle in with a pair of needle nose, it should line it up real easy and give you confidence it went down. I read somewhere recently to have the diaphram in the up position when installing it recently, but I cant see it making any difference as long as the rubber rim is seated correctly in the small lip it goes in. I've done 2 other CV carbs that way.