I recently purchased a 2001 KX250 that has a rear leaky shock (the seal head needs to be rebuilt). If you sit on the bike a few times and work the shock up and down, it will leave a small oil ring around piston shaft. This will also give me a good reason to change the shock oil, I wouldn’t doubt it if it were original fluid….yuck!

In my previous post, KX250 subframe & shock removal/install, will cover how to actually remove and install the shock. This post & video will cover the shock rebuilt procedure as it came on many makes and models.

Service Manual

See this post for a free service manual.

Parts

I chose to buy a genuine, KYB Shock Service Kit 129994600501 from Amazon:

(Please note bleed procedure may differ between models)

2004-2007 Honda CR125R

2003-2006 Yamaha WR250F

2003-2006 Yamaha WR450F

2003-2005 Yamaha YZ450F

2001-2005 Yamaha YZ250F

2001-2005 Yamaha YZ250

2001-2005 Yamaha YZ125

2001-2003 Kawasaki KX125

2001-2003 Kawasaki KX250

2001-2002 Yamaha YZ426F

Make sure to use shock fluid, not fork oil. I chose to use Maxima Shock Fluid in 3W, also from Amazon.

Tips

Rebuilding a shock is surprisingly easy! Here are a few quick tips that I should have done myself that are not in the video:

• Pack the piston rod full of grease before grinding the peened threads off. This will prevent debris from collecting in the port.
• Take pictures as you go! Especially for the valve shim stack!
• Use a propane torch to heat the seal head when removing/installing the new bushing
• Use a heat gun on the piston band to slightly make it more pliable. Be patient working the new band onto the piston. It is a real PITA and took me about 20 minutes.
• After installing the new band, use electrical tape and tightly wrap the band “to size” it back down. I wrapped it about 20 times and let it sit overnight.
• Fill the shock with shop air in small increments and check for leaks everywhere, including the valve core.
• Run a die over the piston rod threads to help the piston & shims come off and on easier.

 Comments

If this video and post helped you out, please comment below.