 Removed the engine so that I could make exhaust system modifications. I was unable to keep the single ball and socket system closed as engine rpm was increased. Over a three month period, I was able to get the engine rpm up to 5500 rpm, but I had so much pressure on the ball and socket joint that the mating surfaces were starting to gaul. And finally, I cracked the muffler support from the flywheel housing and the head clamp that kept the muffler from swinging. At the higher engine rpm, the muffler pipe runs hotter and it lengthens to the point that the socket is forced off the ball, the EGT becomes unstable, and fuel consumption soars.
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 I decided to get away from the one bolt holds it all mounting system to something that was a little more redundant. An one inch thick aluminum clamping ring was placed just below the head and a round the cylinder water jacket. The front part of the ring was left rectangular shaped so that I could drill and tap holes to two small Lord type mounts that stabilize the rear of the muffler and the leading end of the exhaust pipe.
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To keep the muffler from swinging, a tripod was made from thin wall steel tubing and attached to the upper flywheel cover bolt and to two bolts into the front surface of the water jacket clamp. A small bracket was welded to the lower mounting leg to hold a smaller and lighter coolant recovery bottle.
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The original muffler mount was cut away, the muffler was propped up in the desired position with the socket on the ball, and paper template mounts were cut to follow the muffler profiles at the weld lines. These templates were glued to 4130 sheet and the actual parts fabricated and welded to the muffler pipe assembly.
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The leading elbow was cut from the pipe. A Rotax ball was shimmed and welded to the cut end of the elbow. On the other end a small wedge section of the elbow was removed give the Simonini socket a better angle relative to the exhaust manifold ball.
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A small section of pipe was removed from the muffler pipe to maintain over all pipe length. A one-quarter inch wide shim was cut from the discarded pipe to be used to bridge the gap between the pipe OD and the Rotax socket ID. After the elbow was in place on the engine, the socket was slid down on the new ball, the shim slipped into place, the socket and shim raised a little to provide some clearance, and the assembly tack welded. The muffler was removed and the weld completed.
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The front of the muffler was lowered from its original position to gain some profile drag reduction.
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Sandwich clamps were used to compress the ball and socket connections. The clamp side that compressed on the ball on the Victor 1+ had to be modified to reduce the inside diameter.
Also, the compression springs had to be replaced as they were much weaker than the original tension springs that came from Simonini.
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