Home
Basic Dirt Bike How-To's - Video
Dirt Bike How-To's - Video
Living The Moto Life - Video
Bike Tests | Shoot-Outs - Video
Forums
What's new
Latest activity
Log-In
Join
What's new
Menu
Log-In
Join
Navigation
Install the app
Install
More options
Close Menu
Forums
MX, SX & Off-Road Discussions
Dirt Bike Mods & Maintenance
2002 Ktm
Reply to thread
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
[QUOTE="Bud-Man, post: 189381, member: 20830"] On the internal stuff: -Overlap between the main and secondary (bottoming) valving -Added drag of two pistons in contact with the shock body -16mm ID shims -Limited space to work with when building valve stacks on the main piston. -labor intensive to service/revalve Jtt, If you look at the picture of the shock shafts you'll notice the two pistons. The lower piston is the main valve body and the top one is the secondary or bottoming valve body. The main piston and it's valving work throughout the shock's entire stroke but the secondary piston and valving only work when the shock is close to the end of it's travel. If you look closely you will see a spacer between the pistons that has holes drilled in it. Oil passed through the end of the shock shaft and out these holes allowing it to bypass the top piston/valving. When the shock is near the end of it's stroke, it engages a needle mounted on the top of the shock. The needle goes into the end of the shaft and closes off the passage way, which makes the secondary piston and valving active. It works much like a needle jet in a carb and over the past couple of years WP has changed the profile of the needle to alter the damping characteristics of the shock. The oil flow through the shaft and out the holes is the principle stumbling block. It requires a large diameter shaft to allow adequate oil flow which in turn requires shims with larger than normal I.D.s (16mm vs. 12mm on a KYB/Showa/Ohlins). The larger shaft diameter also displaces more oil which can create problems with the passive valving on the compression adjuster. Passing the oil through the shaft also creates another problem as it limits the amount of space you have to work with when building the main valving. The holes in the spacer have to line up with the holes in the shaft for the oil to bypass the secondary piston/valving. Stock, there isn't much room so you have to get creative with the valving. As Jeremy has said before, there are issues with the secondary valving overlapping the main valving, and there is debate about this occuring even when the holes are properly aligned. Passing the oil through the shock shaft makes servicing/revalving the shock more labor intesive as well. When the shock is reassembled you have to take care to align the holes in the spacer to those in the shock shaft. In addition to this you need to make sure the pistons are in line with each other and the seal head. Because both pistons seal against the walls of the shock body, it's very difficult to properly bleed this shock. Even if you specialize in working with this particular shock it will be more difficult and time consuming (i.e. $$$) than a typical shock. Each year WP makes improvements to the design and the '02 shocks have a couple of big improvements as Jeremy pointed out earlier. Unfortunately you still need a lot of special tools to work on it and it's still takes more time. I'll post in about some of the differences in the Ohlins PDS later as I'm retyping this for the second time and my fingers are killing me! :D [/QUOTE]
Verification
Which ocean is California closest to?
Post reply
Forums
MX, SX & Off-Road Discussions
Dirt Bike Mods & Maintenance
2002 Ktm
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top
Bottom