shock interchange

[kelcrist]

i was wondering if anyone has tried a newer shock with high and low speed compression off of say maybe an 02-03  kx250. these are readily available and cheap so i thought i might see about using one instead of springing for a revalve or messing with valving myself. im actually going to try this myself as my son has an 02 250 but before jumping in i thought i would seek some input here.

[kelcrist]

heres an update on the shock............ i have an 02 kx250 shock mounted on my 94 500. it fits but barely. the 250 shock reservoir does not angle down like the 500 so the pipe stinger is kind of pinched between the subframe and the shock.  both shocks are the same length.    the most noticeable difference is the bike doesnt squat or pogo up and down when you sit on it.  ill ride it saturday to see how it compares.   i had to run the rebound clicker almost all the way out and it still returns remarkably slower than the 500 shock. and it compresses much less as well.        so anyways........thats my update.    and in case your wondering...........the 500 shock is in good shape.......serviced 3 months ago,  10 wt oil and a 6.5kg spring because im large. 

[USMC 500]

Thanks for posting this info.....its good to know that there are those out there willing to risk their hard earned money for "SCIENCE" and R&D...

[sandblaster]

heres an update on the shock............ i have an 02 kx250 shock mounted on my 94 500. it fits but barely. the 250 shock reservoir does not angle down like the 500 so the pipe stinger is kind of pinched between the subframe and the shock.  both shocks are the same length.    the most noticeable difference is the bike doesnt squat or pogo up and down when you sit on it.  ill ride it saturday to see how it compares.   i had to run the rebound clicker almost all the way out and it still returns remarkably slower than the 500 shock. and it compresses much less as well.        so anyways........thats my update.    and in case your wondering...........the 500 shock is in good shape.......serviced 3 months ago,  10 wt oil and a 6.5kg spring because im large. 

Interesting, I have had several KX500's over the years.
I have always had my suspension sprung and valved for my weight.
I don't have any pogo problems.
I checked the shock dimensions and your right, it's a good swap although the reservoir does look close.
I'm just curious, the KX500 upper mount width is 2MM narrower then the KX250.
How did you handle the difference?

[Motorrad]

Shims would fix that..

I tryed this with a 08 Kx450 shock..   its a NO GO..   too much in the way.


I want the High speed and low speed external adjustments as well..


Id like to see some pictures of this setup... has my interest.

[kelcrist]

i did not notice any difference in the upper mount.  it fit like the stock shock.   reading your post made me go double check for play and there is none.   not sure what that means.............. as for the clearance issue,  it is not close.....it rubs. a little clearancing of the pipe and subframe would fix this but its not my shock so i will not modify anything to make it work.  i plan on some very light riding and checking often to see how things hold up.       i probably can manage to get some photos. i always have a hard time posting them on posts so i dont do it often.    if you have an FMF pipe it basically looks like its made for the shock. the little up curve it has right at the beginning of the stinger fits perfectly around the shock res.   

now dont misunderstand when i say pogo............ i didnt think my bike did any pogo action either till i put this shock on.  the valving is stock but it has good oil in it so while it is a bit soft it does do what its supposed to.  i know proper valving is needed but i like the adjustments the newer shock has.  if anything id say im oversprung because with the heavy spring the valving just cant keep up with shock speed. but it doesnt bottom unless i do a very bad flat landing.      so anyway........yes in the interest of R&D and bettering all 500s i will take pictures.    there is a MX sunday, i might even race it this way if the test goes well.

[kelcrist]

<a href="http://s342.photobucket.com/albums/o418/princessamber5/?action=view&amp;current=shock4.jpg" target="_blank"><img src="http://i342.photobucket.com/albums/o418/princessamber5/shock4.jpg" border="0" alt="Photobucket"></a>


<a href="http://s342.photobucket.com/albums/o418/princessamber5/?action=view&amp;current=shock3.jpg" target="_blank"><img src="http://i342.photobucket.com/albums/o418/princessamber5/shock3.jpg" border="0" alt="Photobucket"></a>

<a href="http://s342.photobucket.com/albums/o418/princessamber5/?action=view&amp;current=shock1.jpg" target="_blank"><img src="http://i342.photobucket.com/albums/o418/princessamber5/shock1.jpg" border="0" alt="Photobucket"></a>

<a href="http://s342.photobucket.com/albums/o418/princessamber5/?action=view&amp;current=shock2.jpg" target="_blank"><img src="http://i342.photobucket.com/albums/o418/princessamber5/shock2.jpg" border="0" alt="Photobucket"></a>

[kelcrist]

well not sure whats with all the extra links but if you click on bottom link you will see the photo.  if you click the other you get the album and you get to see all the stuff my wife uploaded   hahahaa..............enjoy.....

[kelcrist]

another update............. i skipped the gym tonight cuz i just couldnt stand not knowing how that shock is going to ride.  i can tell you that it is like a transformed bike.  it is much more stable. it got more stable with the stock shock and the heavy spring and now it is even more so.   i was concerned about the geometry of the linkage cuz the rebound was so slow and i let out the adjuster and it didnt seem to change but thats cuz the orifice had not opened.   today it was very springy and i had to return the adjuster to where it was when the shock was on the 250.     for me this shock is a definite improvement.   i couldnt say if its better that a stock shock with the right spring and custom valving. i weight 240  and i have the compression set in the middle and rebound between middle and max.   for me there would be a lot of room for adjustment to soften the ride for cruising or stiffer for an aggresive mx track.  the track i ride is a vet friendly natural terrain track.

also i did not notice any harsh metal on metal sounds and there doesnt appear to be any rub marks yet.  my pipe is firmly mounted with custom mounts at the head pipe and at the mount by the kick starter. i dont use the frame mount under the tank cuz when i fix that mount it either cracks my pipe or just breaks the mount off again. i felt the shock res after a few high speed passes on a canal bank and it does not seem to be pulling heat from the pipe.    i will definitely race with this shock sunday so stay tuned for the next update.

[kelcrist]

well here is probably the final update on this shock. i  have  raced it and it worked well. i cant tell you if your going to enjoy the valving but i did.   so there you have it ......it fits the bike, it works like a shock is supposed t0 work.   i have not decided if im going to buy one to mount permanent because my goal is to make an AF model.    not sure if ill use this bike as donor or buy the pieces to make one when the time comes...................      hope this helps some of you out there.

[Polar-Bus]

well here is probably the final update on this shock. i  have  raced it and it worked well. i cant tell you if your going to enjoy the valving but i did.   so there you have it ......it fits the bike, it works like a shock is supposed t0 work.   i have not decided if im going to buy one to mount permanent because my goal is to make an AF model.    not sure if ill use this bike as donor or buy the pieces to make one when the time comes...................      hope this helps some of you out there.

Just an FYI you may want to remove the spring, install the shock and move the swingarm through it's stroke. As you move the swingarm through it's fulcrum the shock actually pivots on the upper mount this "could" potentially cause a mechanical interference with respect to the resivior that you are not aware of because it "might" only happens when the suspension is collapsed...

[kelcrist]

not an issue. the top of the shock is shaped the same as the 500. the only thing that is in the way is the exhaust pipe.    it left a very very very small mark on the res.

[ELRUKO]

Most under the tank pipe mounts are broken and useless.  I found that 2 of the large zip ties routed thru the pipe bracket and frame  pillar of the coil supports the pipe and acts as a flex mount.  My pipes have not cracked due to frame flex at the pipe mounts.

[kelcrist]

so now i have a dilema.........now that i went and told everyone that my shock works fine.......i looked down after the last moto last week and guess what.      it is leaking.    no surprise really,  probably never been worked on.   i was thinking i serviced it but thinking back that was on my 92.    so anyway......buy the 250 shock or service this one???   of course one way or the other the original shock will be rebuilt so what to do??

[kelcrist]

heres a little note that may help others in the future...........   if you dont have an FMF gnarly pipe this shock will not fit. i tried to fit my pro circuit pipe on and it will not fit with the 250 shock.  the fmf pipe has a little bend that clears the shock reservoir.     i did not try my stock pipe.