In preparation for fitting the muffler onto the 4 exaust pipes, each exhaust pipe needs to be loosened up so that it can be wriggled into the muffler. Since each exhause pipe is sealed to its corresponsing engine cylinder with a copper gasket (a crush seal), the pipes need to be completely removed and a fresh gasket installed in their place before fina tightening after muffler installation.
Each pipe is secured to its cylinder with 4 allen screws holding a plate in place. Those 5mm allen screws are recessed pretty far up inside the cylinder structure. My 5mm allen wrench is about 3 inches long. Yep, it took me about 30 minutes to get the first pipe off ... one quarter turn at-a-time! After an hour, I had managed to get the #1 and #3 cylinder exhaust pipes removed and back in place with new crush seals, but I was out of arm strength (arms over my head for an hour) and bodily fluid (sweat) to be able to continue.
Today I will purchase a long (8 inch) 5mm allen wrench which should reduce the pipe removal/replacement time down to about 5 minutes.
#3 Cylinder exhaust pipe with allen screws, old (flat) seal (left) and new (uncrushed) seal (right),