The exhaust thread in the head of the Jadus Test Mule 1.0 finally gave out
Swapping headers around and bolting down the clamp flange a few times did it. If you look closely at the hole you can see the old bolt is actually still there - in the middle of where the new thread should have gone. But sadly, the muppet that did this repair job failed to extract it and then just decided that a new M6 tapped hole, 3mm to the right at a 15 degree wrong angle was good enough. Same person that bolted in a wood screw remember! Gah.
I took it as a sign. I am going to do a full rebuild of this engine eventually and make a separate build thread of it. I'll get that exhaust thread repaired properly with the head off - hopefully even welded up and re-tapped in the correct position. I have lots of ideas for the build... Cam, high comp piston etc. It's gonna be a killer.
In the mean time, plans go ahead to complete the testing on the Jadus Test Mule 2.0