I would also agree with the exhaust pipe theory,as I was the same about 20 years ago for my GS,"Ill just blow ahole through that X-member and bung it straight out, with a quote about $200
NO says I and went to a different exhaust shop, who followed the original route with a straight through "hotdog" type of muffler up between the centre members and then following the route out to the right useing the original hangers,first system lasted from 1991 until 2011 all in 2" (50mm) pipe, gave me slightly better HP and fuel ecomoney,and on long uphill grades like the gateway bridge in Brisbane :Bellowed Like a Bull
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cheers