JD 425 20hp Kawasaki valve specs

JohnC425 · Oct 1, 2014

I have a 1998 JD 425 with the 20hp Kawasaki engine and would like to adjust the valves - could someone help me with the following?
-valve settings
-does this engine use flat gaskets or o-ring style gaskets beneath the valve covers
-the rocker adjustment nut torque value
-the valve cover bolt torque value
the engine serial # is: FD620D130255
Thanking you in advance

beenthere · Oct 1, 2014

:welcome: to TBN
I'll look in the tech manual for those numbers later today.. if you don't already get them from another member.

A good idea for you would be to secure a tech manual.. well worth the price.

What I found:
re: -the rocker adjustment nut torque value
Valve clearance adjustment nut 79 lb-in
Rocker arm adjustment screw locknut 79 lb-in

re: the valve cover bolt torque value
Two listed for "crankcase cover cap screw" at 186 lb-in, and for the same item 17 lb-ft.
(I suspect the first is really for the Rocker arm cover and is an error, as the 455 diesel shows Rocker arm cover is 160 lb-in)

Valve cover gasket is of the o-ring style (i.e. not flat)
Pic of the valve settings as follows:

DrBill · Oct 1, 2014

The info I have says o-ring style gaskets and 0.010 in. on both intake and exhaust..

beenthere · Oct 2, 2014

Here is a pic of the head showing the valve cover gasket.

Gittyup · Oct 2, 2014

I think on some of the later year models the valve covers were changed to metal and use flat gaskets. On the 1995 model I owned, it used oring gaskets that don't want to stay in place. Definitely easier to use gasket compound to hold them in the groove when putting back on. With the plastic valve covers, do not over tighten. A common mistake that leads to leaks. You can retrofit to the metal covers and flat gaskets, if so desired.