1991 KDX 200 Rebuild

TheGriz · Post by **TheGriz** » 12:36 pm Sep 30 2016

Lubed the piston and cylinder with 2T oil. Pinching the rings and installed the cylinder onto the engine:

TheGriz · Post by **TheGriz** » 12:44 pm Sep 30 2016

I'm pretty frustrated with the cyclepedia manuals instructions on the KIPS installation. it tells you to install the cross shaft before installing the side valves... I couldn't make that happen. My side valves needed to go in before I could install that cross shaft. I've got some questions coming.

Main exhaust valve assembled and installed:

I installed the left/right side valves and the cross shaft. With the cross shaft pulled out all the way to the stop, I aligned the marks.

Left side valve aligned with the scribed mark on the cross shaft.

Right side valve and idler "dots" facing each other:

When you look into the exhaust port with the cross shaft pulled all the way out, this is what you see. Both left and right valves are open. But what is the center valve supposed to be doing when they're open?

With the cross shaft all the way in, this is what I see.

To you guys who have done this before, what am I supposed to see with that center valve?

TheGriz · Post by **TheGriz** » 12:52 pm Sep 30 2016

I just found this thread: http://www.kdxrider.net/forums/viewtopi ... ve#p144044

I'm going to pull the cylinder back off and try his method tonight.

ubareddition · Post by **ubareddition** » 02:05 pm Sep 30 2016

Pulled all the way out the center valve is supposed to be fully open. I had a trick for getting it but I'd have to be home to remember. I think you push the cross shaft in till the end of it is flush with the cylinder then take your fingers and try to get the center valve teeth to catch on the center shaft while pulling on it.

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ubareddition · Post by **ubareddition** » 02:08 pm Sep 30 2016

Should have made a video.

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TheGriz · Post by **TheGriz** » 06:02 pm Sep 30 2016

Urbareddition - Is this what you mean by the center valve being fully open?

ubareddition · Post by **ubareddition** » 01:15 pm Oct 01 2016

Look down from the cylinder. Into the port what do you see?

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ubareddition · Post by **ubareddition** » 01:15 pm Oct 01 2016

Oh wait... is your piston in already?

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TheGriz · Post by **TheGriz** » 09:34 pm Oct 01 2016

The piston is in, but down at the bottom of the stroke, below the exhaust port. You can easily see the main exhaust valve.

Here is what I think is what you guys are considering open. In this picture, the curve in the exhaust valve matches the curve in the cylinder:

In this picture (hard to see), the circular side of the valve blocks the curved opening at the top of the exhaust port. I guess that would be closed:

TheGriz · Post by **TheGriz** » 09:36 pm Oct 01 2016

I think I answered my own question when I described the closed position, lol.

I'm so used to powervalves with a flapper in the exhaust port.

ubareddition · Post by **ubareddition** » 12:12 am Oct 02 2016

Yeah looks good.

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TheGriz · Post by **TheGriz** » 09:51 am Oct 03 2016

More on KIPS installation:

I was perplexed as to why my 1991 didn't have the same alignment mark as the later model.

I then realized that my center valve has a curved groove in it that allows the cross shaft to slide past the exhaust valve without spinning it. If you pull the center valve out just slightly, you can move the cross shaft easily. When you pull the cross shaft out to line up the side valves, leave the center valve pulled out slightly so that it doesn't move. After you get them lined up, push the center valve in and mesh the gears with the cross shaft. The flat spot on the end of the center valve should be at the 12:00 position when they are all open. How did I miss this??? It was so easy.

Looking in the exhaust, they are all open when the shaft is pulled out. BOOM!

New head gasket:

New O-Ring and bolts in the center cover:

T-Stat cover and new gasket/bolts. Head bolted down.

Post by **KDXGarage** » 12:57 pm Oct 03 2016

Sweet! I love these threads.

Friedom · Post by **Friedom** » 01:33 pm Oct 03 2016

Nice find! Mine didn't work when I tried doing it that way, but it looks like you found the easy it SHOULD be.

"Good job, guys. "

TheGriz · Post by **TheGriz** » 05:38 pm Oct 03 2016

Big thanks to Ubareddition for sending me a governor shaft. It arrived today, before I could get back in the machine shop to finish mine.

Ceramic coated the KIPS cover:

New water pump seal:

Replaced the outer cover bearings:

Inserted the new governor shaft and lined up the guide pin with the groove in the centrifugal unit:

Inserted the retaining pin in the slot:

Retaining screw:

New kick start seal:

ubareddition · Post by **ubareddition** » 06:35 pm Oct 03 2016

Oh there's a retaining pin that goes in there. Now that makes sense. Cause it doesn't really work with just a screw.

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ubareddition · Post by **ubareddition** » 06:36 pm Oct 03 2016

What's the tool you used to remove the outer cover bearings.

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TheGriz · Post by **TheGriz** » 10:00 pm Oct 03 2016

ubareddition wrote:What's the tool you used to remove the outer cover bearings.

With the alignment dowels removed, I placed the cover flat on the bench, used a torch, heated up the crankcase cover around the bearings and gave a tap. They dropped right out. My IR thermometer said 180deg F.

TheGriz · Post by **TheGriz** » 10:03 pm Oct 03 2016

Gasket and crankcase cover replaced. I used some RTV here as well.

Be sure to put the gasket on before connecting the governor lever arm. This time I remembered that it was LEFTY tighty.

This governor shaft is a little different. It has a hole in it that I used to stop the shaft from turning while the nut was tightened:

TheGriz · Post by **TheGriz** » 09:30 am Oct 04 2016

I should have split cases, even if only to media blast them. I'll be needing a way to scrub them once I get the engine closed up.

If anyone has any cleaning recommendations that don't involve splitting the cases, I'm all ears. I suppose I could try to mask it all off well and blast it, but that seems a bit risky.

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