2007 klx250s Carburetors, Jetting, and Sound
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2007 klx250s Carburetors, Jetting, and Sound
I have a 2007 klx250s with a random Chinese 32mm carb on it. The listing said it would fit the bike, but with it being a 32mm, it obviously doesn't. I'm pretty young, but I do a lot of the wrenching on my bike along with my dad. He had the idea to use a certain kind of tape to wrap around the carb as the rubber boot (I believe) was too big for it.. It takes around 1-3 seconds for the rpms to drop back down to idle, but besides that it runs pretty decent. I'm looking to get a 34mm NIBBI carburetor (specifically this one https://tinyurl.com/4hhfxjee), but I'm wondering what jets I should put in it. I would have to change the throttle cable too as the carb I have on it now is a CVK opposed to the NIBBI one being a PWK. I live around 30-40 feet above sea level, so I'm just wondering if anyone has any recommendations of what jet kit I should put on the bike.
The other thing I'm wondering is about the deep knocking sound when it's moving at low rpms, around 1000-2000. This happens when accelerating from 1st gear, or when I shift too early any give it too much throttle. It's not like a bogging noise or rod knock noise, but it's a deep thudding kind of. I have the mp3 file attached, but it sounds louder and a little deeper than it does with the mic I have in my helmet.
The other thing I'm wondering is about the deep knocking sound when it's moving at low rpms, around 1000-2000. This happens when accelerating from 1st gear, or when I shift too early any give it too much throttle. It's not like a bogging noise or rod knock noise, but it's a deep thudding kind of. I have the mp3 file attached, but it sounds louder and a little deeper than it does with the mic I have in my helmet.
Last edited by daxust; Apr 24, 2025 at 10:31 PM.
Junior Member
Joined: Jan 2025
Posts: 3
From: Ontario, Canada
Hey daxust,
I guess the first thing to understand is what are you hoping to achieve with this carburetor setup?
The stock CVK34 has a lot of advantages from the development work already done on this forum. Those data sets are quite valuable to have and will save you a lot of hours of pulling carbs, integrating parts and generally pulling out your hair. If you want the fastest path to a good running bike then I would highly suggest sticking to the tried and true CVK34. They have a surprising bandwidth of performance they can support. I imagine you could find a decent used one fairly cheaply and order the jets/ needle you need fairly easily.
If you want a bit of a science experiment, then you can mess around with a slide carb. You are going to have to spend time researching and will probably spend twice as much money and time to end up at nearly the same place as the CVK. Its a lot of work getting unfamiliar components to work together seamlessly generally speaking. It may be worth it to you for the learning exercise, but you should go in with both eyes open. Of course, if you can find someone else who has worked out the kinks already, you can get a jump start from that but always trust but verify any information you don't get from a primary source (even then be su****ious!).
If you want to put the audio on YouTube, I'd be happy to listen but I get a bit sketched out when I have to download a file to listen to it.
1000-2000 RPM + acceleration is way too low to be healthy for the engine. Sounds like you are lugging the engine so I am not surprised its complaining.
I guess the first thing to understand is what are you hoping to achieve with this carburetor setup?
The stock CVK34 has a lot of advantages from the development work already done on this forum. Those data sets are quite valuable to have and will save you a lot of hours of pulling carbs, integrating parts and generally pulling out your hair. If you want the fastest path to a good running bike then I would highly suggest sticking to the tried and true CVK34. They have a surprising bandwidth of performance they can support. I imagine you could find a decent used one fairly cheaply and order the jets/ needle you need fairly easily.
If you want a bit of a science experiment, then you can mess around with a slide carb. You are going to have to spend time researching and will probably spend twice as much money and time to end up at nearly the same place as the CVK. Its a lot of work getting unfamiliar components to work together seamlessly generally speaking. It may be worth it to you for the learning exercise, but you should go in with both eyes open. Of course, if you can find someone else who has worked out the kinks already, you can get a jump start from that but always trust but verify any information you don't get from a primary source (even then be su****ious!).
If you want to put the audio on YouTube, I'd be happy to listen but I get a bit sketched out when I have to download a file to listen to it.
1000-2000 RPM + acceleration is way too low to be healthy for the engine. Sounds like you are lugging the engine so I am not surprised its complaining.
Last edited by KXLDirtScooter300; Apr 29, 2025 at 02:10 AM.
Thread Starter
|
Junior Member
Joined: Apr 2025
Posts: 4
Hey daxust,
I guess the first thing to understand is what are you hoping to achieve with this carburetor setup?
The stock CVK34 has a lot of advantages from the development work already done on this forum. Those data sets are quite valuable to have and will save you a lot of hours of pulling carbs, integrating parts and generally pulling out your hair. If you want the fastest path to a good running bike then I would highly suggest sticking to the tried and true CVK34. They have a surprising bandwidth of performance they can support. I imagine you could find a decent used one fairly cheaply and order the jets/ needle you need fairly easily.
If you want a bit of a science experiment, then you can mess around with a slide carb. You are going to have to spend time researching and will probably spend twice as much money and time to end up at nearly the same place as the CVK. Its a lot of work getting unfamiliar components to work together seamlessly generally speaking. It may be worth it to you for the learning exercise, but you should go in with both eyes open. Of course, if you can find someone else who has worked out the kinks already, you can get a jump start from that but always trust but verify any information you don't get from a primary source (even then be su****ious!).
If you want to put the audio on YouTube, I'd be happy to listen but I get a bit sketched out when I have to download a file to listen to it.
I guess the first thing to understand is what are you hoping to achieve with this carburetor setup?
The stock CVK34 has a lot of advantages from the development work already done on this forum. Those data sets are quite valuable to have and will save you a lot of hours of pulling carbs, integrating parts and generally pulling out your hair. If you want the fastest path to a good running bike then I would highly suggest sticking to the tried and true CVK34. They have a surprising bandwidth of performance they can support. I imagine you could find a decent used one fairly cheaply and order the jets/ needle you need fairly easily.
If you want a bit of a science experiment, then you can mess around with a slide carb. You are going to have to spend time researching and will probably spend twice as much money and time to end up at nearly the same place as the CVK. Its a lot of work getting unfamiliar components to work together seamlessly generally speaking. It may be worth it to you for the learning exercise, but you should go in with both eyes open. Of course, if you can find someone else who has worked out the kinks already, you can get a jump start from that but always trust but verify any information you don't get from a primary source (even then be su****ious!).
If you want to put the audio on YouTube, I'd be happy to listen but I get a bit sketched out when I have to download a file to listen to it.
I have school tomorrow, but when i get home i’ll put the audio on youtube for you. Just a side note, if the file is a .mp3 (audio) or a .mp4 (video), there’s nothing to worry about as it’s only an audio/video file. I understand the su****ion and i’ll put it on youtube, but i’m just letting you know.
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