Maintenance & Technical > KX450F / KX250F
KX450 valve clearance
ThrottleJunky:
I think that's what I have.
The valve/seat contact area on my head was too big on the diameter. I didn't have all of the special tools to resize the seat angles so I used one of my resources for help. He sent the head back complete with new valves, guides, and springs. He even installed a new exhaust gasket. This is his specialty but I think it's time to check out what valves are actually in there...
ThrottleJunky:
More information:
Dug my 08 head out of my buddy's aluminum recycle bin. Slid an old 08 valve all the way in the guide. Depth mic'd from the face on the top side of the head to the valve stem.
Did the same with the set up I was trying to assemble (don't know what head I actually have -think it's an 07).
Approx. .200" difference between the two. That's the gap I had between the tapppet and cam!
(remember 07 and 08 have the same cams, valves, springs - only difference is the head)
That's hard evidence the combustion chambers were extremely reconfigured between 07 and 08!
Still waiting for the word from my head connection to see exactly what he gave me...
1989kawasaki:
4 strokes sound like they are a PAIN IN THE .......
don46:
--- Quote from: ThrottleJunky on January 30, 2011, 06:09:17 AM ---More information:
Dug my 08 head out of my buddy's aluminum recycle bin. Slid an old 08 valve all the way in the guide. Depth mic'd from the face on the top side of the head to the valve stem.
Did the same with the set up I was trying to assemble (don't know what head I actually have -think it's an 07).
Approx. .200" difference between the two. That's the gap I had between the tapppet and cam!
(remember 07 and 08 have the same cams, valves, springs - only difference is the head)
That's hard evidence the combustion chambers were extremely reconfigured between 07 and 08!
Still waiting for the word from my head connection to see exactly what he gave me...
--- End quote ---
I don't think the combustion chamber being different is your issue, valve train is the same, so if you compared your 08 valve to whatever it is that you have and your off by .200, well theres your problem. it sounds like your builder used to short a valve.
The 06 and 07 were the nastiest KX450f's they mellowed them 08 and newer, I have valves that I can mic for length, you can pull your valves and measure them as well, that will tell you whether or not you have the right valves.
ThrottleJunky:
Problem Solved!!!!!!!!!!!
I aquired a brand new, out of the box, 08 head. Took an old valve and slid it in place and mic'd from the top head face to the stem tip. Same measurement as my grenaded head. GREAT!!!!!!!!!
Don, your right, my builder put something on me that I can't identify. I thought I was going NUTS! I do appreciate your helping me work through this issue.
Doug, thanks for the help also.
Time to get busy and finish this project!
George
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