Fettling a Kawasaki KMX 200

[slowlydoesit]

[dangerousdave]

I doubt you'd find a new one now. Not a Genuine Kawasaki part anyway.

In the past I've used secondhand HT coils on my Thunderace, wouldn't hesitate to do so again. They are still going after 30,000 miles.
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1988 Kawasaki KMX 200

Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50

[dangerousdave]

What about these:
https://m.ebay.com/itm?itemId=310734617595
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1988 Kawasaki KMX 200

Previous: Yamaha YZF1000, ZZR600, KMX200, DT50, KX80, CG125, PF50

[slowlydoesit]

[dangerousdave]

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So, today I went and did some work on the KMX200 with the help of my long-suffering friend. To recap, the bike idles fine and runs well at small to medium throttle openings, but stutters and misses above around 6,000 rpm or at wide throttle openings.

We had agreed to whip the head off and that's what we did, probably took us 30 minutes, including rooting about for a container for the coolant and trying to find the right size spanners and sockets. Then we took out the KIPS valves.

https://i.imgur.com/JwHHOVJ.jpg

Now I'm left with a conundrum. As far as we can see, the KIPS valves were inserted properly and if you move the rod that is supposed to rotate the valves, the valves open and close. However, the cutouts in the valves seem the same, whereas the valves shown in the official Kawasaki service manual and the Haynes book have different shapes. Here's what the manual shows:

https://i.imgur.com/FmmArWK.jpg

Notice how the cutout is straight across in the valve on the left and diagonal across the valve on the right. And here's a random image plucked from elsewhere on the web - again, different cutouts:

https://i.imgur.com/KjFN2fo.jpg

Oddly, although my valves have the same cutout shape, they seem to come from different stock. Note that end of one of them is blunt and closed whereas the other has a bevel with a hole punched in the end. Also, look at the shape of the teeth of the cog - clearly different. So it looks as if they were made by different suppliers.

https://i.imgur.com/EJlQ3HB.jpg

What do I have here? A mismatched set of powervalves? But if you look at the site BDK Engineering, which makes and sells two-stroke parts, their valve kit looks like this - just like mine and both with the same shape cutout. Curiouser and curiouser.

https://i.imgur.com/2I9h8iJ.jpg

What's going on?
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Kawasaki KMX200 with broken fixed powervalves and a stutter

[dangerousdave]

[slowlydoesit]

[stevo as b4]

AFAIK the early alloy valves were handed, and the LHS and RHS were different shapes. I remember when I bought a new OEM Kawasaki valve to replace the snapped one in my first KMX200, that the new valve was a different shape to the old one. I queried this, but it was the updated part no.

So basically new valves will not be handed like the old ones were, and looking at your valves they appear to be the original Alloy versions, hence why they seem to have suffered with the lower part of the spindle snapping off after a partial seizure. My LHS valve broke in the same way, but it was the upper part of the spindle that broke off, just below the gear.

Either way you really need a new set of valves or a good second hand pair.

[slowlydoesit]

[stevo as b4]

It's not always easy to get the broken bits left in the cylinder barrel out in situ. They normally are stuck in place with oily gunk, and if you can't pull them out with needle nose pliers etc, you might have to take the barrel off. If the top guide bushes aren't worn then re-use them, but it's recommended you replace the O rings, and use a high temp grease on the rack and pinion gears.

I'm not sure about the BDK valves, but on the Kawasaki OEM ones, there are two dots that line up with grooves on the operating rack to time the valves up. It is physically possible to fit them backwards and then they don't work too well.

[slowlydoesit]

[dangerousdave]

[dangerousdave]

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[dangerousdave]

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