Author Topic: 2000 OEM Steel Frame Build: Which Fork? OEM or 01 CR125?  (Read 4006 times)

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Offline manco

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2000 OEM Steel Frame Build: Which Fork? OEM or 01 CR125?
« on: April 25, 2016, 04:13:47 AM »
I am at the point of getting a front end together for my 00 KX500 build. My choices are the original KX500 OEM or a 01 Honda CR125 front end. I have done some research on the two forks and found that they are both roughly the same KYB fork except for dampening internals. Outer and inner tubes are the same and will direct swap into the OEM KX500 triple. Both forks run the same seal and dust wiper kits. As for what is the difference between the two its the dampening system for the CR125 adds a bladder system to help with midstroke. The bladders though weren't set up well from the factory and are harsh in the midstroke because of it. A few remedies for the harsh midstroke when the fork is on a CR125 is there is some kind of mod that can be done to overcome the bladder issue, I believe parts from a newer cr125 fork can be swapped in, or the bladder can be taken out and the whole shock re valved which I believe would make the shock more similar to the KX500 OEM KYB. What I am trying to do is pick which fork to use that would be the easiest to tune in for MX riding. On the one hand maybe the OEM CR125 fork may be fine as a straight swap since the KX500 is heavier. On the other hand if the CR125 fork is gonna be a hassle of modding and re valving to in the end just create something similar to a OEM KX500 KYB then what would be the point of messing with it.

Also too into this decision:

The OEM KX500 fork has definitely seen lots of use over the years though is in good condition. The CR125 fork is nice with only around 50 hours on it total since new.

Either fork I pick I will be using the CR125 front brake as it fits both forks.

Should I pick one fork over the other? or should I maybe build one fork from the two? Has anyone ridden a 97-04 KX500 with a 00-01 CR125 fork?
"Never contend with a man who has nothing to lose.”
― Baltasar Gracián

Offline manco

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"Never contend with a man who has nothing to lose.”
― Baltasar Gracián

Offline manco

  • Full Member
  • ***
  • Posts: 113
"Never contend with a man who has nothing to lose.”
― Baltasar Gracián

Offline manco

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Re: 2000 OEM Steel Frame Build: Which Fork? OEM or 01 CR125?
« Reply #3 on: April 25, 2016, 07:22:10 AM »
It turns out I spoke a little soon about these forks being a straight swap. While the triple clamp upper tube mounting points are only 1mm smaller in diameter on the CR125 upper tubes it is enough to require a shim to mount the CR125 tubes into a OEM KX500 triple clamp. For a straight swap it would require the CR125 lower tubes in KX500 upper tubes. The shims could possibly be made with a heavy gauge beer can. All bottom tubes are the same diameter.
« Last Edit: April 25, 2016, 07:26:11 AM by manco »
"Never contend with a man who has nothing to lose.”
― Baltasar Gracián

Offline manco

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Re: 2000 OEM Steel Frame Build: Which Fork? OEM or 01 CR125?
« Reply #4 on: April 25, 2016, 07:47:10 AM »
Ahh scratch this. I am gonna stick with the OEM KX500 front end. Leaving the above info behind for anyone interested.

Also here is some more info. The upper tubes of the Honda CR125 forks are approximately 3/8" longer then the KX500 upper tubes. The lower tubes of both forks stick out of the upper tubes the exact same length. The overall difference from top of the upper tube to the middle of the axle on the CR125 fork is roughly 1/2" longer compared to the KX500 fork. There must be 3/8" difference from upper tube + 1/8" added in the metal below the lower tube before the axle mount and/or the axle may differ in distance how far it sticks out on the CR125 fork. I can't tell for sure but I think the KX 500 axle mounts closer into the lower tube by a few mm.

« Last Edit: April 25, 2016, 08:12:15 AM by manco »
"Never contend with a man who has nothing to lose.”
― Baltasar Gracián