Jump to content

2003 kx125 carb

Recommended Posts

Hello all I'm new to this forum so please excuse me if this is a sore subject. So I have a 07 kx 250 and my son has a kx125. His bike kinda bogs in 1st and 2nd gear. I bought the bike used so not too knowledgeable about it. Anyway the carb has some gas coming out so I assume carb needs cleaned or rebuilt. That said I believe I just want to buy a new carb for him but don't want to spend the $500 for the oem part. Any good aftermarket carb u can recommend? Mikuni or keihn? Size any info would really be appreciated. We just ride for fun so I don't know a ton about this stuff. Thanks

Share this post


Link to post
Share on other sites

I bet you could sort that carb out in under an hour without replacing any parts.  Take it apart and clean it.  Make sure the jets are not blocked or plugged.  Blow some carb cleaner through the passages and make sure nothing inside the carb body is blocked up.

If the gas is coming out of the overflow the floats are probably stuck.  The bowl is probably full of dried up gas and its clogging up the works.

If you do decide to swap a different carb I would probably recommend a screw top Keihin.  Mid 90's KX250.  Would require substantial rejetting and tuning to get it running right.  Lot more work to do that than to clean your existing carb. 

  • Like 1

Share this post


Link to post
Share on other sites

Mikuni carburetors are synonymous with the devil, but if setup correctly, should be adequate for your needs. No point in buying new until you at least take yours apart. Buy at least 2 cans of carb cleaner and blow out EVERY passage really well. Also, pull the jets and blow them out really well.

 

Typically, I will note, that two stroke carbs dont clog up with nastiness. The oil in the gas keeps the gas from breaking down like it does in 4 strokes. I still turn my gas off when I am getting close to the truck to run it out as fur as I can.

Share this post


Link to post
Share on other sites
1 hour ago, smelonas said:

Mikuni carburetors are synonymous with the devil, but if setup correctly, should be adequate for your needs. No point in buying new until you at least take yours apart. Buy at least 2 cans of carb cleaner and blow out EVERY passage really well. Also, pull the jets and blow them out really well.

 

Typically, I will note, that two stroke carbs dont clog up with nastiness. The oil in the gas keeps the gas from breaking down like it does in 4 strokes. I still turn my gas off when I am getting close to the truck to run it out as fur as I can.

I never understood the Mikuni phobia.  I ran them for years on my 125's.  They work like anything else does.  They jet the same way.  Kawasaki and Honda used them on 125's and 250's.  Carbs a carb. 

  • Like 1

Share this post


Link to post
Share on other sites

Using locknut idle adjuster screws, jets that can't be changed with the bowl on, constantly changing jetting in different times of the year because they are so finicky, cold morning warm afternoon jetting is impossible to keep together. The worst experiences I have had jetting came from mikunis. Keihins are always so easy to dial and they stay dialed.

Sent from my SM-N910V using ThumperTalk mobile app

Share this post


Link to post
Share on other sites

Not my experience at all.  My 03 KX125 ran year round with the same jetting.  Air screw adjustments took care of the rest.  If I remember correctly the TMX definitely had a removable drain at the bottom of the bowl.  I don't think I've ever seen a modern carb that didn't.  Some have them but are impossible to access without removing the carb, aka the Keihin PWK38S with the throttle position sensor.  Jetting is just like any other carb.  Lean out the pilot for up to 1/4 throttle, needle clip for 1/4 to 3/4 and the main for WOT.  No mystery at all.  Before I got on thumpertalk I never heard anyone bitch about them.

They're just not that bad.  I never adjust idle either.  Set it and forget it.  When it won't idle anymore it needs a top end.

  • Like 1

Share this post


Link to post
Share on other sites

Oh they all/most have a drain.. but can you access the jets? And then can you access them easily? Personally, to me, I don't really care what the bikes comes with because if I don't like it, I just change it out. Chump change is nothing to complain about..

 

Sent from my SM-N910V using ThumperTalk mobile app

 

 

 

 

Share this post


Link to post
Share on other sites
On 8/29/2017 at 5:23 PM, turbo dan said:

I bet you could sort that carb out in under an hour without replacing any parts.  Take it apart and clean it.  Make sure the jets are not blocked or plugged.  Blow some carb cleaner through the passages and make sure nothing inside the carb body is blocked up.

If the gas is coming out of the overflow the floats are probably stuck.  The bowl is probably full of dried up gas and its clogging up the works.

If you do decide to swap a different carb I would probably recommend a screw top Keihin.  Mid 90's KX250.  Would require substantial rejetting and tuning to get it running right.  Lot more work to do that than to clean your existing carb. 

Just like turbo dan Said Check the float and the needle to make sure its not getting stuck and allowing too much gas through. 

Also another things that I don't think was mentioned, What is your fuel mixture?? Are you running 32:1 because too much oil could cause your bike not to combust right. 

Before spending all the money try cleaning first, and a change in fuel mixture could solve the problem. Check your idle screws Air and Fuel.:ride:

Share this post


Link to post
Share on other sites

Can't remember who I bought the carb from but can u please text me 484-942-7914. Carb works great but the throttle adjustment screw on the new carb is larger then what I had. So I was going to order a new assembly for it as it works well. I just don't know what one to order?? Didn't think the carb came off a kx125. Thanks

Share this post


Link to post
Share on other sites
1 hour ago, Scottiey1 said:

Can't remember who I bought the carb from but can u please text me 484-942-7914. Carb works great but the throttle adjustment screw on the new carb is larger then what I had. So I was going to order a new assembly for it as it works well. I just don't know what one to order?? Didn't think the carb came off a kx125. Thanks

Sent text

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×