The cat would prevent anything from getting back to the motor.
Unless they packed the muffler with gravel won't be a problem. Ride it.
I thought. You Buddy may not want to ride right behind you... <grin>
Ride safe, Ted
PS: Delkevic is the least expensive slip on available. Looks pretty good to.
if you get a longer one not overly loud.
As I noted in my explanation, any gravel shoved down the hole from the back, simply cannot migrate up, and forward out of the mufflers inner baffle system. The pipe coming from the front, enters the can, and is attached, protruding thru a plate, into another "perforated can", where another plate lives at the rear of that section;, a couple of metal tubes are welded to that, and go rearward into a third divider section, where the output "pipe" is attached.. Unfortunately, as all the "tubes" protrude "into each can's internal areas", anything in there is trapped, and cannot be "shaken out"; physically impossible for stones to migrate to the exhaust pipe, or even into the path against the cat converter.
I can't find the actual photos of mine when it was "modified", but mine has the forward and second plate removed, which removes the dual "S" shaped paths that exhaust gas' must travel to exit the rear.
again, removing the rear painted aluminum end "adornment" will reveal the welds of the outer can, to the inner assembly... 5 minutes with a die grinder, will remove the welds around the perimeter, and it can all be "pulled out from the rear"... then you can see the sections, and mess around with the stones.. and if desired re-install, and mig weld the end again.. really not a monster of a job... been thinking of doing "cutdown" mufflers for a $$ lately, any interest??? Mind you, shipping the 21 lb. muffler, in a box can be pricey, but in the end, it still works great, and looks better than the newest ZX1400 monstrosities.. OEM...