It should work. I added lighter clutch weights go give it better take offs. Go to Rebelgears.com for gears. Not the cheapest , but they will get you in the right direction.

 

UPDATE!!!!!!!!

I think I might have a solution for the CDI box that limits the rev's. Im gonna need a few weeks for me to wire up a new harness and a different CDI box(secret box). Meantime , Im gonna head down to the local Kawaski dealer and do some comparisons. This should work for the KFX50 AND 90 if I figure this out. My original CDI has a white sticker on the side of it. "30400-PVA1-900 /2006. AUG" .
PLEASE!!!!!!! Somebody give my the number off of the KFX90 CDI box!!!! That way , i could at least eliminate one of two options!!!! The only reason Im doing this stuff is that my son wants to race , but Im not gonna set him up for failure with a bike that barely go's over 15MPH against bikes that do 20mph+

 

I'm gonna remove the collar today but I'm interested to see what you find out about the CDI box. I been looking all over for a solution for the speed problem. Luckily I found this forum.

Here are the numbers off my boys '07 KFX90 - 30400-DVA2-900 2006.AUG

 

Unfortunatlly , It didn't work. The little Kawi has a 12vdc powered cdi box. Lifan atv's make a four wire system. I have seen the high rev cdi's on ebay, but they are listed in different countries. I think it will work , just not willing to take a chance on oversea sellers or shipping. I did get the kfx90 cdi box, that didnt work until I rewired it , then I found it to have the same rev limit as the kfx50(lame).

 

CDI box issue has been resolved!!!!

 

Anyone do an exhaust yet on the KFX or the Mongoose 90? Thats my next purchase for my boy's M90...

 

<div class="FTQUOTE"><begin quote>Originally posted by: cliffymiracle

Anyone do an exhaust yet on the KFX or the Mongoose 90? Thats my next purchase for my boy's M90...</end quote></div>

Cliffy , I personally don't know if the pipe will do much good. I went ahead and ported out my son's head(exhaust side). That exhaust port was small as hell. Also modified the rear spark arrestor. That seemed to help alot. I know you could get the Two bros pipe. Also , I think FMF finally has a pipe out for around $200.00(for the 4-stroke). Power core 4. Anyways, If you get the pipe ,let us know what ya think.

 

could you please list the suppliers names where you purchased the parts for your kfx50. i bought this fourwheeler for my daughters and it slooooooow!!!!!

 

Did you remove the speed reduction collar first?

 

Hi. I know this is an old post but I removed the collar. The bolt keeps loosening up on the clutch when we start it up. How tight do you make that bolt on the pulley. If I go tighter the belt gets crushed inbetween please help. jsantoro32@yahoo.com