OK, job now done...
Cutting open the standard exhaust exposes...
heat resistent wool held in place by a wire mesh.
With the wool and the mesh removed you can now see the cat.
The cat was cut out and weighs just over 500g
Somewhat freer gas flow now!
The flap welded back again
The cutting, removal and welding cost 20dh (about �1.60) though I gave the guy 30dh as he did such a good job.
Engine response is crisper throughout the rev range, it revs to higher engine speeds more freely and I've gained flexibility lower down. Some of the farting and belching backfires on the overrun now sound more like .22 rifle shots.
So all plus at this stage.