At this point in your struggle, applying a load of heat to the valve joint won't hurt. It'll fry the seals but new ones are needed anyway. For the joint seal SiA128 I've used a Buna O-ring from my box-o'-stuff that seemed suitable in size, worked fine. The exhaust seal is a flat one, looks like urethane, and an O-ring wouldn't likely work here. Pretty sure I once cut one from 90 durometer urethane sheet, but didn't record the dimensions.
Don R.
Mark.....
If you could do this, I would forever be in your debt.... and I would even buy you a beer!
But seriously though.... that would be the answer to my prayers!
I have no idea of the sizes of the seals etc, and besides, I think this current valve may have been butchered a bit. There are a lot of scratches on it, and it looks like it has been through a vice (seriously).
So..... I will be sitting on the edge of my seat in anticipation!
regards
Mike