KX500 AF Build

[jacquedup]

Hi there,

Thanks for giving me access to this mass overload info site on kx500's, glad to be a part of it. I am from South Africa and I am going to attempt building a kx500af.

I have bought a KX500 that needs lots of love and a kx250f with a busted motor.

I have started stripping my 500 motor and found a few issues already. damaged piston. it has excessive piston and cylinder wear at the outlet side. the cooling system is filled with orange gunk and the clutch is completely shot.

so I definitely need a top end overhaul. My question is: while the motor is open, what all needs to be replaced? I will check the clearance measurements on the crank with a feeler gauge set to check the spec. but what is all best to replace without splitting the motor?

Last week by chance I came across a 1996 KX500 and the following day I stumbled on a 2007 KX250F that has motor damage. Surely this must be fate and the universe telling me that I should build it.

So I drove and picked up the bikes. My wife is not very impressed. She says I have enough toys... Really? can one really have too many toys?

Just the fact that I found a KX500 is amazing. They are seriously scarce nowadays, in South Africa that is.

So this is what I have started out with..

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[jacquedup]

I have cleaned up the KX motor and started stripping it to see what needs to be done.

Problems found so far:

1. Power valve incorrectly connected
2. Piston heavily worn on outlet side
3. Sleeve word on outlet side
3. Clutch plates are missing a lot of small pieces
4. Cooling system is filled with a lot of orange gunk

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[jacquedup]

I am trying to loosen the Clutch Hub nut, but it is seriously stuck. I have a tusk clutch holding tool. I looked in the manual, but could it possibly be right thread instead of left?

[Sandblaster]

OK, I combined your other topic with this one... Makes it easier
A couple of things, the forks off the KX500 are from 91-93 so unless someone swapped the front end out it is somewhere in that range.
Not a big deal as there is only a couple of changes in the engine from 89-04.
If you were in the USA I would tell you to send me the VIN and I could tell you for sure but we have a couple of ways to narrow it down.
You carb should have the following ID: V563 If it is any other ID let me know.
KEIHIN PWK V563 FITS 90-93 KX500 - 39MM
FlyWheel ID: F4T102 71 If it is any other ID let me know.
F4T102 71 FITS 89-91 KX500 - 21007-1183 - 2.55lb or 41.6 oz. - 4.370" OD
And what is the diameter of the chrome fork tubes. 41 or 43mm?
The Clutch hub is a standard Righty tighty, lefty loosie
I use a impact gun on mine to loosen them. Bbbbrrrraaaapppppp... Done..
Except every once in a while someone puts the nut on with loctite.... In that case we generally have to heat them first...

[Sandblaster]

Look at the inside of your clutch cover close to the window.
Typically they are cracked.
Now would be a good time to repair it.
Also, look at your cylinder carefully.... you want to inspect around the tops and bottoms of the intake bridges as well as the exhaust ports.
There is where you will find the majority of cracks.

[jacquedup]

Got the clutch Hub off by heating the nut thanks.

Here are some more pictures.

I have measured the crank and all is within spec. When I rotate the crank it moves with slight resistance and there are no rough spots or any noises.My crank measured 0.020 which is still within new spec.

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[jacquedup]

I also found a crack in the clutch cover

[jacquedup]

Here are some close up pictures of my piston and cylinder. It actually looks like there is a piece of the piston stuck to the cylinder wall.

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Here is also a picture of one of the clutch plates and a couple of them look like this.

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[jacquedup]

My Cylinder needs to go in for Nikasil plating. So I need to remove everything from the cylinder.

I am battling to remove the KIPS system.
I am following the manual but the idle gear moves slightly up and down but does not pull out. Not sure if I am missing something?

[Sandblaster]

Sorry for the delayed answer, my lap top bit the big one and I've been stuck with no internet access at home so I got to work early to get this done.
The Kips valves often get very sticky.
You need to get some penetrating oil and really soak them through the exhaust port.

Here:

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Here:

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After soaking try to move the valve a little up and down:

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