KDXRIDER.NET

i wanted to give everyone an update on this, bought my bike and it was running rich, had a 155 main, 45 pilot. bike has fmf gnarly pipe, half the airbox lid cut, twin air filter. i was down to a 140 main and 35 pilot, and bike ran better, but not great, and was about ready to replace the carb, after putting a new needle in it and cleaning it/setting the float level several times. anyway, i replaced the formed o ring assembly under the main jet holder, and the bike was instantly lean. i now have a 45 pilot in it and 155 main, and the bike runs great and throttle response is crisp, i bought the oring from jets r us. i recommend when rebuilding a problematic carb to just replace it, even if your bike is an '06 that oring is 9 years old. just wanted to share what i found, hopefully this saves alot of people from buying a new carb.

What part is it? I am looking at their blown up diagrams and can't see to find it.

Thanks!
Jim

Only o-ring I see in the diagram is that for the float bowl drain plug. I don't see how that could affect its running rich or lean.

https://jetsrus.com/individual_parts/021_532_su.html
Its not shown on any exploded views Ive seen. It goes between the jet block and the carb body. Remove the two tamper proof torx screws and remove the jet block.

royadams wrote:https://jetsrus.com/individual_parts/021_532_su.html
Its not shown on any exploded views Ive seen. It goes between the jet block and the carb body. Remove the two tamper proof torx screws and remove the jet block.

+1 You need a security torx bit. Usually see this problem on carbs that are dipped, causes the gasket to swell and deform. Once the jet block starts leaking it will always be rich. Documented in lots of places on here here, and here, and here, and so on,, etc

Glad to here you've got it sorted!

That damned jet body o ring causes all kinds of problems! I bought 6 of them over the years- always keep spares!

I have some little ghosts in my carb. Called my brother and he believes a shop "soaked" it overnight when they had it in like 6 years ago.

Ordering that baby today!

Thanks,
Jim

one of the cheapest fixes i've ever done, i was about ready to replace the carb, fixed for 10$ with shipping!

Thanks for posting ,,, I didn't even know it existed

Now I have to remember it exist , dam :(

I was unlucky enough to replace my jet block oring and not fix my problem. Now I wonder if my pipe is a desert and not a woods pipe, would a stock pipe help? Thanks for advice. I have the same rich on bottom if I don't keep revs up, runs good at higher rpm. maybe reeds? can I tell if reeds are bad by sight?

Reeds will cause rich like symptoms
What jetting are you running now?

152 mj, 42 pj, DEL needle - central Illinois

This thread should be a sticky, my kdx still runs great! Just got done reading on page one of people complaining about running rich, hi fuel consumption, etc. This probably would fix most of those problems, and a carb rebuild should include replacing this seal

Hmmm good to know! Mine runs like a dream, but I'll definitely remember this incase I ever do have any such problems. Sounds like it's kind of a common thing

Thanks for posting! This fixed my carb problems!

No kidding. If this jet block gasket is on the way out, your bike will dog.

Mine wasn't as bad as some o rings I have seen, but still not perfect. I went from a bike that set off OK and then sputtered instantly in the mid range to a bike that will stick the front wheel in the air with just a whiff of throttle, and then charge through the mid range with no issues.

Now, my top end is dead feeling....KIPS totally not working which is getting worked on right now.

ill try posting this here...my kids 95200 spooges big time! it has lean pilot...it still loads up badly...main seems good....running jd needle (leaner of the two)on #1....runs great when on the pipe....changed jetblock gasket...floats set numerous times...didcthe water test to see if inlet needle was leaking...passed. not sure what else it could be?? any suggestions?

argclh6670 wrote: not sure what else it could be?? any suggestions?

I doubt it, but worth asking. I am assuming the reed valves are good?

Have you done the LP gas test around everything with it running?

never heard of the LP gas test....reeds look good.

19Delta wrote:

argclh6670 wrote: not sure what else it could be?? any suggestions?

I doubt it, but worth asking. I am assuming the reed valves are good?

Have you done the LP gas test around everything with it running?

Have bike at slow idle, open your valve on your LP gas torch valve, but DON'T light it. Rub the tip around anywhere the engine could be sucking air. If you've got a hole or crack in a boot, or a bad gasket somewhere, the engine speed will rise when it sucks the gas vapor in.

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