Try revving the bike with your hand over the exhaust, pressure should increase , right ? Does the bike ( exhaust ) sound quieter than usual ? If the owner doesn't care I think I'd get a big screwdriver and bust thru' the end of the baffle in the exhaust anyway, the CX 4 into 2 is real quiet, lots of baffling in there.... IMO.
Also is the battery O.K. ?, holding-up and charging good ? Wish I could help with a trailer, but some ideas to keep it at the top of the page !!