Power Valves

[cyclebradd88]

I was out ridding last weekend when I realized my 1990 KDX200 was loosing all kindso of power. It is an Eric Gorr top-end with a milled base on race gas. I noticed after looking that the rod that actuates the power valves was able to be moved in and out with my fingers. It must be borken somehow inside the clutch-side case. Any ideas what happened, and is it tough to fix? I fixed it on the trail by using a zip-ty to keep it "on the pipe" WOW! That thing ran like a maxed-out 125 MX on Steroids!

 

[cyclebradd88]

I did some searches in the forum, and I'm sure it is the governer. Unless someone replies here, I will assume the cover is coming off, and parts are going to have to be purchased!

 

[89kdx200rdr]

is the nut on the govenor lever loose? i dont think it's keyed, but not sure.

 

[bigred455]

Sounds like the lever comp governor shaft. Pull the inside clutch cover off and see if it is broken.

 

[cyclebradd88]

Wouldn't that be sweet if it was just a loose nut! I'll check that for sure.

 

[canyncarvr]

The actuating rod usually breaks. The reason it does usually break is due to non-support of the shaft during disassy/reassy.

I realize yours is not a 'H' model. Still, a '90 parts diagram shows a nut on the top of the shaft. In the 'H' model, this is a LHT nut. Point of that is that it often is tightened when it's meant to be loosened. Even when turned the correct direction, the shaft must be supported when wrenching the nut.

There is a governor shaft lever on the bottom of the actuator shaft that is held on with fasteners. It may be loose.

In any case, I'd suggest you don't ride the bike...don't even kick it over until you get the problem resolved.

Little pieces may well by lying around inside the RH cover just waiting to grenade your motor.

.......it's happened before!!

 

[louis]

The pin will break from the lever,pass between kick starter gears,break off
teeth and all this debris will then wedge it self between the clutch basket and the case. This all happens real fast. You will get to know your UPS driver very well.

 

[cyclebradd88]

I pulled the side cover (finally) and discovered that the piece that rides in the groove of the govenor was snapped off. This is going to be an easy and cheap fix...wahoooo!

 

[canyncarvr]

Great!

It could've been expensive HUGE! You lucked out!

Keep in mind why they usually break!

 

[cyclebradd88]

Originally posted by canyncarvr
Great!

It could've been expensive HUGE! You lucked out!

Keep in mind why they usually break!

What normally causes them to break??

 

[canyncarvr]

From a post above:

I realize yours is not a 'H' model. Still, a '90 parts diagram shows a nut on the top of the shaft. In the 'H' model, this is a LHT nut. Point of that is that it often is tightened when it's meant to be loosened. Even when turned the correct direction, the shaft must be supported when wrenching the nut.

From the same post just a bit further above that:

The reason it does usually break is due to non-support of the shaft during disassy/reassy.

.....wrenching on the nut without supporting the shaft.

 

[HareNHound]

That part that broke probly broke because the KIPS assembly in the head is getting sticky with 2 stroke. While you have the tank off buy a base and head gasket and take the power valve apart and clean it. It will also give you a good reason to replace your piston bearing and compression rings. You can check the action of that power valve by turning that gear. If it feels at all sticky pull it apart.