air box fitting on a 99 KX frame

Discussion for swapping a KDX motor in a MX frame...
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bulabula09
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air box fitting on a 99 KX frame

Post by bulabula09 »

hey fellas...ok, so iv started trying to fit the air box...i decided to go with the KX air box and the KDX carb boot and just fab a bracket to make them fit together. i have encountered a problem that i havent seen anywhere on this forum...my rear suspension spring rubs against the boot where it connects to the carb. and i cant move the boot over any farther as the frame is in the way. has anyone encountered this problem yet? i need some opinions on how to fix it..thanks much :supz:
-cam
KarlP
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Post by KarlP »

On my CR build the spring also rubs on the boot, but very lightly and doesn't seem to do any harm. I had it all apart recently to check on that.

It may be that you need to rotate the motor forward just a bit. I hate to say it but the airbox fit should have been mocked up while figuring out the motor mounts and pipe fitment.

Not very helpfull, I know.....
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Tedh98
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Post by Tedh98 »

Do you have any pictures?
bulabula09
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Post by bulabula09 »

yes...i can post some pictures tonight...and Karl, i see what your saying...i guess i got a little lazy in that i didnt want to make new front motor mounts...im suffering because of it now..lol :neutral:
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canuckhybrid125
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Post by canuckhybrid125 »

The part #1430 is on my air box boot,and looks like its from a 1991 KX125.Its about 1"shorter.But yeah post a picture first.
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bulabula09
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Post by bulabula09 »

this is the best angle i could get..sorry i had to take it on my phone


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Tedh98
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Post by Tedh98 »

Have you put your pipe on yet? I was asking b/c it almost looks like the engine is tilted too far back, causing the carb/boot junction to be right at your shock. If your pipe is way off, that might tell you something.

I don't remember seeing that problem in any of the other builds that used the '99 style frame.

How does it look/fit if you use the KX boot?
bulabula09
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Post by bulabula09 »

the project is at my parents house right now...im going back wednesday of next week and ill snap some more pics of the pipe fitted up...for now this is the only picture i have of the pipe and airbox on at the same time...
The KX boot was way to big..it actually hit the back of the motor where the carb fits in...thats why I decided to go with the KDX boot which was a whole lot smaller...i have noticed that the KDX boot seems a little fatter around the area where the spring is than the KX boot...the boot is from a '91 KDX..could that be the problem? the motor is a 2000 year model....one last thing...would it make a huge difference if maybe i got some zip ties and pulled them around the boot to "thin it up" a little bit...or would that affect the ammount of air the carb sucks in?


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KarlP
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Post by KarlP »

It does look like your motor is tilted back just a bit too much. The boot/carb joint looks like it is almost into the spring. I suppose you could try squezing the boot with zip ties. I'd be worrying about them breaking sometime in the future and your spring knocking the boot loose from the carb
Does the tank fit?
You may have to back up a bit and redo the front and lower two motor mounts. Your pipe might stay like it is if it does not end up hitting the front tire.
Motor mounts need to be made last after it is confirmed everything else will fit around the motor.
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canuckhybrid125
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Post by canuckhybrid125 »

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bulabula09 wrote:the project is at my parents house right now...im going back wednesday of next week and ill snap some more pics of the pipe fitted up...for now this is the only picture i have of the pipe and airbox on at the same time...
The KX boot was way to big..it actually hit the back of the motor where the carb fits in...thats why I decided to go with the KDX boot which was a whole lot smaller...i have noticed that the KDX boot seems a little fatter around the area where the spring is than the KX boot...the boot is from a '91 KDX..could that be the problem? the motor is a 2000 year model....one last thing...would it make a huge difference if maybe i got some zip ties and pulled them around the boot to "thin it up" a little bit...or would that affect the ammount of air the carb sucks in?


Image
Here's mine yours looks pretty much the same.Image
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canuckhybrid125
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Post by canuckhybrid125 »

>|<>QBB<
KarlP wrote:It does look like your motor is tilted back just a bit too much. The boot/carb joint looks like it is almost into the spring. I suppose you could try squezing the boot with zip ties. I'd be worrying about them breaking sometime in the future and your spring knocking the boot loose from the carb
Does the tank fit?
You may have to back up a bit and redo the front and lower two motor mounts. Your pipe might stay like it is if it does not end up hitting the front tire.
Motor mounts need to be made last after it is confirmed everything else will fit around the motor.
The spring is mounted to the frame so if the engine was off it should'nt matter.Unless you mean that the carb is pushing the air boot into the spring.
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Post by KarlP »

Mr Canuckhybrid 125-

Tells us about the kick lever on your hybrid!

See the post about the shorty lever in the product review section

http://www.kdxrider.net/forums/viewtopic.php?t=8058

It looks like you have a solution to a vexing problem!

As far as motor position, yeah it looked like the shock spring was up against the air boot enough that the spring motion would work it loose from the carb. That was the OP's original concern.
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canuckhybrid125
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Post by canuckhybrid125 »

>|<>QBB<
KarlP wrote:Mr Canuckhybrid 125-

Tells us about the kick lever on your hybrid!

See the post about the shorty lever in the product review section

http://www.kdxrider.net/forums/viewtopic.php?t=8058

It looks like you have a solution to a vexing problem!

As far as motor position, yeah it looked like the shock spring was up against the air boot enough that the spring motion would work it loose from the carb. That was the OP's original concern.
Its a 98 KX125 kicker but you have to use a 98-02 KX250 boss because of the splines on the shaft.I dont know if you could just get a 250 assembly that would work,but I got the kicker for cheap so I just bought another boss.This is mounted on a hybrid not kdx,just so you know.
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bulabula09
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Post by bulabula09 »

I dont believe the motor can be moved any farther foreward as the swing arm pin doesent allow it to move...the bottom of the motor is about 1mm to 2mm from the frame so i dont think it can move any farther foreward or down...i may try to cut a larger hole in the air box to allow the carb. boot some room to be moved over a few mm's and clear the spring. any other suggestions....or does this sound like a good idea?
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Post by KarlP »

I saw your lower mounts. Your motor is just about on the frame rails. It does not look like it can go much closer.
Redoing the air box sounds like the way to go. It is a KDX boot on a KX box, correct? Those two parts weren't necessarily meant to go tegether so if you are having to make an adapter plate anyway, that plate can be used to shift the boot to the left.

It'll work, nothing but time and more time. Maybe a litlle money... :supz:
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canuckhybrid125
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Post by canuckhybrid125 »

Just started to put my bike back together it looks like on mine also the very top of the spring is touching the airbox boot where it meets the carb.I might try a little heat to see if I can shape the boot.
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2004 TTR 125 LE
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