My bogging between 5-5500 rpm is back (did the Klxster lid off upgrade). I had gotten rid of it after tearing the carb apart a couple of times, but over the past couple of weeks it's been coming back slightly more on each ride.

FYI...2007 KLX 250S, lidless, DJ2152, 2N, 152 Keihin (same as DJ140), stock header and Q4 slipon, stock pilot jet 35, 3.5 turns out

I'm at a loss.....going back in to clean everything extra good....any ideas?

Otherwise, upgrading to a pumper carb.

 

i would go back make everything super clean and install a filter on the fuel line

 

Kevin, only thing I can think of - given that the issue has slowly returned - is a gradual build-up of stiction that increasingly prevents normal slide operation. I'd concentrate on the cleanliness of the slides' "channel" in the carb casting as well as the slide itself. The slide operates in a "filtered air" environment and there should be absolutely no debris/dust/residue/etc anywhere inside the carb and its' "slide area"..

You noticed that manually operating the slide with your finger showed a marked difference - between malfunctioning carb and functioning carb - perhaps do this test first ?

Perhaps an initial Q-Tip swab of the slide area, once apart - checking for anything that could have "built up" on this area and caused stiction..?

It's important that you cured your stuttering with a careful "dis & re" assembly of the slide system.. Now that its' gradually returned, perhaps you can identify the new cause.

 

Thx Klxster....I'm hoping this will fix it again. What is your favorite cleaner/method? I know I have to be careful what gets on non-metal parts.

 

I've never seen anything inside my carb castings that even hinted of dust/debris/residue.. Always spotless and sterile looking in mine.. So I have no idea what/how to clean up the inside.. I do have a few thoughts tho..

Items (off the top of my head) that probably should not see contact with cleaners - choke plunger tip, tip of fuel needle (in the bowl), butterfly shaft seal(under/inside the return spring on the butterfly shaft), diaphragm.

If I've missed a component, hopefully other members can add to this list..


If increased stiction is the cause, you certainly have a problem that is allowing unfiltered air into your carb/slide assembly - possibly unfiltered fuel could do this as well ?

 

After having the same debilitating problem on mine and swapping carbs completely fixed it, Im inclined to believe it is slide/diaphragm related. I say this because the slide on the carb that fixed the problem was ultra smooth, while the original seemed to have a spot where it was not as smooth/ like the diaphragm was not releasing air fast enough/etc.