does anyone know Inner Diameter of kx250 steering stem bearings

[motorsickleman]

im trying to figure out if i can swap my 500 forks into a 01 kx250 frame.  i have the frame, the 500 forks. but no bearings.  from what i've looked up, the 92-06 kx250 stem bearings are all the same.  if anyone has one they can measure this will help greatly.  i need the inner diameter of both upper and lower bearings.  or if someone has swapped these forks then some insight would be appreciated. 

p.s.  the bottom 500 bearing seams to be the right dimensions but the upper is the one that will not swap willingly.  oh and this applys to sf conversion cause this i part of my 500/250 project

recap: trying to find kx250 bearing dimensions to put 500 fork/clamp assembly on 01 kx250 frame.

[alward25]

The 500 forks should fit the 250 clamps.  The 500 stem bearings are different.  I can measure if you would like the 500 bearing dimension.  I know YZ 250/426 forks fit on the 500.  The caliper fits too.  The axle is different but the upper fork is all the same.
Good luck

[don46]

maybe old 250 froks will work, the newer stuff is to big, you can mod it and make it fit but then the rake is wrong if you use newer clamps. I would be suprised if the YZ forks fit the 500 as they are basically the same as the newer 250 KX forks, but hey I've never tried yamaha stuff so it could be.

Motor, what you can do is press out the stem of the 500 and press it into the 250 triples, you'll have to make a spacer for the top clamp

[alward25]

Not sure how old we are talking, 04 (unless a 04 WR426/250) and newer would not work.  But 98-02 stuff would work. 46-47mm type. 02 426 forks fit my 01 500 clamps.

Alex

[sandblaster]

Hey, your right...
I do not claim that this is a complete list, but these are ones we have measured over the years:

YZ250 98-02 UPPER 53.9MM - LOWER 58.4MM - BRAKE C/L 102MM

KX500 97-02 UPPER 53.8MM - LOWER 58.9MM - BRAKE CALIPER C/L 102MM

CR250 97-01 UPPER 53MM - LOWER 58.4MM - BRAKE MOUNT C/L 102MM

YZ400F 98-99 UPPER 53.9MM LOWER 58.4MM - BRAKE MOUNT C/L 102MM

yz426 00-01 UPPER 53.9MM LOWER 58.4MM - BRAKE MOUNT C/L 102MM

[alward25]

Very helpful list Sandblaster
Alex

[sandblaster]

Hey Alex.
I'm always adding this kind of info here:
http://oem-cycle.com/BikeIdentification.aspx

[motorsickleman]

thanks for all the info, what i was trying to do is find the inner diameter of the kx250 bearings to see if they would fit with the kx500 stem, using the kx500 clamps stem and forks.  i may just go the route of putting my 500 forks into the 250 clamps if that will indeed work.  otherwise it looks like the lower 500 bearing will fit into the 250 frame

[motorsickleman]

if anyone else is doing this type of swap i will post the info after i figure it out.  I looked and found that the bearings for the 01 kx250 are the same in a 04 kx250f which i happened to pick up last week so i will be checking the bearings and/or the stem dimensions for compatibility.  this is the only thing i havent figured out yet, already got the 500 swingarm in the 250 frame done.