Power Valve Question

[kx100pro]

I just got a '94 KX500. I rode all day yesterday around a small track with a nearby field. The bike ran fine and started really easy. However I think the powervalve my be stuck. The reason being that the bike sat for about 2 years now before I bought it. I had a 500 in the past and it seemed to rev much higher and faster than my new one.

My question is this: Where is the power valve. I tried searching buykawasaki.com on the parts diagram, but I couldn't find anything. Thanks for any help.

[DrMojo]

I am checking my power valve(s) too.  The valves are located in the "jug".  You can see part of them if you remove the pipe.  The actuating mechanism is located on the right side of the motor (if you are sitting on the bike).  You can remove the small plastic housing (has a small rubber boot on the base).  Removing the two screws will expose the valve actuating shaft.  The light gray colored cover is about 2" by 1 1/2" or so.

You should be able to grab the mechanism and pull it towards you.  The action should be smooth with no rough spots.  If this works the valves are not stuck.  The next step is to start the motor and rev the engine.  I believe that the little arm should move once the motor hits 5,500 to 6,000 rpm.  I need to do this test on my bike too.  If the valve actuating lever does not move, you have an internal problem.  The small plastic drive gear inside the right-side engine cover may be damaged.

I suggest you buy a shop manual so you know where all the parts go once you start taking things apart.

Let us know what you find.

[John]

There is a lot of information available on the net with regards to service and maintanace on the KIPS valves. I think Eric Gorr wrote a good one.

If the arm in the cyllinder head mooves smothly (the valves in the cylinder head) - do not take it apart.

If the actuator does not open the valves your problem is likely to be under the right hand engine cover. There is a mechanism witch uses centrifugal force / balls and and preloaded springs. In my old KX5 some stuff is made of plastic - my 125 is only aluminium..?

Having looked closely and repaird a crashed one, I would say that the function of the actuator is binary. Either it works - or not. I could be stuck as well... There is a preload spring, if that spring is worn, it would only cause the valves to open easier / earlier.

To have a look, tilt the bike or drain the oil and dismount the right hand engine cover. Check out the links for more details.

Eric Gorr http://www.eric-gorr.com/twostktech/twotopweb_2t.html

Kawasaki http://www.buykawasaki.com/Default.asp?strContentURL=Site/VIVehicleInformation/VIVehicleInfo.asp?intCatalogID=2&CatalogTypeID=4&ProductTypeID=10&ModelMarketingID=138&ModelYear=1989

On Kawasaki, go to parts diagrams.

/John