KIPS question

[David M]

Going to look at a '98 KDX220 this weekend. I just read an article on the KIPS valve by "Canadian Dave" and it mentioned that the KIPS valve can seize causing the geared advancer shaft to strip the gears from the sub port valves rendering them useless.

Is there any way I can tell if this has happened? In the article he mentions that there is a loss of low end power, but since I'm not familiar with how a well functioning KDX feels, I'm not sure if I'll know.

Anything else you think I should look for when checking this bike out?

-David from Canada (but not Canadian Dave)

 

[jaguar]

You could take off the actuator cover on the upper right hand side of the engine and check that it "actuates" the KIPS when you blip the throttle to high revs.
If it does then the mechanism near the clutch is good.
So then take the pipe off and also disconnect the same actuator (opposite thread. make sure you hold the "arm" to keep it from moving while unscrewing the nut or else you'll break off the dodad arm near the clutch) and move the actuator in and out while looking into the exhaust hole to see that the valves are opening and closing.

Ride it and shift through all the gears to make sure they all work good.
Also check for clutch slippage.

 

[canyncarvr]

On a '98, you can remove the slotted cover on the LH side of the bike and use a ratchet/socket to rotate the assy. No disconnecting of the actuator required.

Then, as jag says, look into the exhuast port (pipe off) to see the main valve and the subports move as the should and return as the should. The main valve will raise on activation, the subports will rotate in sync to open on activation. The whole thing should return to 'at rest' by itself when you release pressure on the nut.

Note there is a detent ball underneath the rod right at the nut on the LH side. If it's clean and working, you'll hear a 'snick' when you first turn the nut, and hopefully a like 'snick' when the main spring (on the clutch side of the motor) returns the KIPS back to its static state.

Check the suspension, too. It takes consistent maintenance to keep the unitrack/swingarm bearings in good shape.

 

[Canadian Dave]

Hi David M,

Not to worry this isn't a problem on 1995+ KDXs and only effects 1989 to 1994 KDX200s. In 1995 the KIPS system was redesigned to eliminate this problem.

Things to watch out for include the condition of the rear suspension linkage. Bike manufactures are really skimpy on grease especially on the rear linkage. Unless the previous owner has disassembled the rear linkage and properly greased it chances are good the bearings are in poor condition. Elevate the bike and gently rock the swing arm back and forth and up and down. There shouldn't be any slop in the system.

If the piston hasn't been replaced with a Wiseco piston you should factor than into the cost of the bike. The stock piston is poorly designed and becomes overly stressed if the bike is ridden hard or the engine has been modified and cracks. A Wiseco piston will eliminate this problem and give you some piece of mind.
If the top end has been rebuilt talk to the owner about the KIPS advancer shaft. It need to be properly supported when removing the nut on top. If not the shaft can snap and potentially damage the clutch or engine cases. You can read more about this in the Tech Tips section of JustKDX. Your goal it to find out if the owner was aware of this and took the proper precautions. If not then I’d think about replacing the shaft just in case, they’re cheep. If the top end hasn’t been serviced or was serviced by a dealer then don’t worry about it. This isn’t a big problem or something that should deter you from buying the bike just something you should be aware of.

Unless you get into a bike that’s been badly abused you shouldn't have any problems with the KDX220. KDXs are durable bikes and very trouble free.

David

 

[David M]

Thanks for the replies. I'll post after looking at (maybe getting) this bike.
-david m