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1991 KDX 200 Rebuild
Posted: 06:33 pm Sep 04 2016
by TheGriz
Re: 1991 KDX 200 Rebuild
Posted: 11:29 pm Sep 04 2016
by KDXGarage
Re: 1991 KDX 200 Rebuild
Posted: 05:06 pm Sep 05 2016
by TheGriz
I will be needing a new intake manifold. I see a number of them on EBay but they appear to be for the H-series. Does anyone know if they cross over? They look similar...

1991 KDX 200 Rebuild
Posted: 05:09 pm Sep 05 2016
by TheGriz
I located a cylinder and piston. I think I'll send them to millennium for some love and TLC.
This was all that came out of the radiators: I guess that crack is in a cylinder water jacket...

1991 KDX 200 Rebuild
Posted: 06:55 pm Sep 05 2016
by TheGriz
1991 KDX 200 Rebuild
Posted: 06:58 pm Sep 05 2016
by TheGriz
Removed the e-clips and the groove that the lever arm rides in:
Removed the T-Stat housing and behold, I broke another bolt. Time for me to slow down and start to soak everything in penetrating oil:

1991 KDX 200 Rebuild
Posted: 07:02 pm Sep 05 2016
by TheGriz
So I can remember what plug was last run in the bike:
Bleh!!
The head and squish band look pretty good:
Everything is going to soak in penetrating oil tonight:
The most used tools in my shop right now, are the parts washer and blast cabinet:

1991 KDX 200 Rebuild
Posted: 07:11 pm Sep 05 2016
by Singlespeed92
It won't be boring to me at all,my friend,I've always had a hankering to do what you're doing with this one but have yet to give it a try (not the most mechanically inclined person here,but my best friend and riding buddy is the head mechanic at my preferred local shop,so I'm learning here and there

),PLUS the KDX I recently picked up in trade (from the same friend) is a 1991 white one,so doubly interested in this thread. Subscribed. Have fun with it,can't wait to see more

1991 KDX 200 Rebuild
Posted: 07:21 pm Sep 05 2016
by TheGriz
Good to hear. I did a similar step-by-step engine rebuild on a gasgas earlier this year and enjoyed documenting it. It really helped me reassemble as well.
I found new steel power valves here and just placed an order:
http://bdkraceeng.co.uk/tc/products.php?253
1991 KDX 200 Rebuild
Posted: 07:44 pm Sep 05 2016
by TheGriz
If anyone has an old governor shaft laying around (part number 49114-1067) I'd be interested in talking.
I suppose i could weld it up and chuck it in a lathe and re-thread it, but that sounds like a ton of work.
Edit - Just talked to a machinist buddy. He seems to think that making a new shaft will be easier and better than cobbling up the old one... more on that coming soon. Got to love a machinist!
Re: 1991 KDX 200 Rebuild
Posted: 11:54 pm Sep 05 2016
by KDXGarage
Great job on the pictures and info. It is quite interesting to me.
I was going to suggest BDK, but you already found them.
Correct plug is going to be an 8 heat range, unless you are riding in the desert or at high RPM often. For woods, an 8 is the ticket. B8ES for the cheapest, BR8EIX for the best.
Re: 1991 KDX 200 Rebuild
Posted: 08:23 am Sep 06 2016
by TheGriz
Thanks. That should make it easier for me. I have plenty of plugs in the 8 range.
Question: Is the Governor shaft reverse threaded? That could have been my problem. I found this thread that says a 1995 shaft is left hand threaded, but my lever arm looks nothing like that.
http://www.kdxrider.net/forums/viewtopi ... rnor+shaft
1991 KDX 200 Rebuild
Posted: 12:51 pm Sep 06 2016
by KDXGarage
I know 1995 and newer are. I can not remember if it is for 1989 - 1994.
Re: 1991 KDX 200 Rebuild
Posted: 04:07 pm Sep 06 2016
by david
TheGriz wrote: Is the Governor shaft reverse threaded? That could have been my problem.
Yes, they are.
Re: 1991 KDX 200 Rebuild
Posted: 04:13 pm Sep 06 2016
by TheGriz
Thanks - I should have picked up a manual.
There was a gasket in the exhaust port:
Removed the water pump cover:
More nasty stuff:
Removing the kick starter:

1991 KDX 200 Rebuild
Posted: 04:21 pm Sep 06 2016
by TheGriz
So that I don't have to store nasty dirty parts and then spend an entire day of cleaning parts, I am trying to get them cleaned up as I go:
Back to the power valve:
It took some heat cycles to loosen this retaining bolt:
Removed the right side guide:
Removed the center valve bushing:
Removed the governor rod:
Removed the left side exhaust valves:
Teeth are in pretty bad shape:
Removed the center exhaust valve:
Removed the right side exhaust valve:

Re: 1991 KDX 200 Rebuild
Posted: 04:26 pm Sep 06 2016
by TheGriz
Re: 1991 KDX 200 Rebuild
Posted: 04:27 pm Sep 06 2016
by TheGriz
I found this guy on the towel... Apparently, it goes inside the clutch basket.

1991 KDX 200 Rebuild
Posted: 04:33 pm Sep 06 2016
by TheGriz
Clutch bushing:
Spacer/washer:
I removed the bolts that hold the right side crankcase cover on...
I found the pin from the governor shaft behind the clutch basket:
Removed the set screw that holds the governor shaft in place and removed the shaft:
Here is the broken pin. This pin rides in the centrifugal assembly (governor)"

1991 KDX 200 Rebuild
Posted: 04:33 pm Sep 06 2016
by TheGriz
I found these on my towel:
EDIT - Looks like the wave washer goes in the KIPS center valve. Still looking for a home for the flat washer.