1983 KX500 Detonations and Piston

[ibpassngas]

I have a 1983 KX500, yes an old air cooled monster.  I put a new OEM piston in and immediately fried it.  It made one lap at Southwick pinging and detonating miserably before it quit.  Kawasaki had single ring pistons in the KX500 thru 1987 I think.  My piston is a single ring design and no longer available from Kawasaki.  The bore/stroke are same as the later 1988 on up models and my question is does anyone have experience or think a currrent double ring KX500 piston would work in my 1983 KX?  Also, the piston siezed on the sides so I guess it got hot.  The pinging would suggest I need timing adjustment and/or head modifications.  Any thoughts?  Detonation was a chronic problem for this year/model.  I have a PVL ignition and set the timing based on the specs but still have these problems.  thanks

[mr.5thou sand]

did u have old gas.how bout crank seals .what about your jetting

[ibpassngas]

new gas with Maxima 927 Castor 40/1, old crank seals, new mikuni 38mm flatside carb with 45 pilot and 280 main (per specs).  Plug didn't look too bad.  Light brown no white.  I ran 2 head gaskets like the original magazine test recommended in hopes of toning down the detonation.  I also timed the ignition to 1.1mm BTDC as recommended.  Maybe that was too agressive and caused the blast furnace?

http://vmx.livewire.gen.nz/magazine/83KX500/83KX500.htm

The piston and ring fused together on each side of the piston and lost compression.  The front and back side of the piston looked fine.  No parts of the piston or ring broke.

I know the bore/stroke is 86mm x 86mm which is same for all KX500's.  It uses the same rod, piston pin, and top end bearing.  Only the single ring piston is different.  Curious if a current model double ring piston would work.