Carpy's pipes look like they should work well and price is not too bad, especially if he helps etc,
My 'smith honda cr750' which rob wittey took to victory in 750, and 1300 uk classes last year, went through several types of exhaust in its racing life, initially with 4 into 4 open megga's, then we went to 4 into 1 sytems, and a larger can for baffling to get within uk sound regs.
I imported one of the curved hand bent yosh systems from japan (not the same as carpys) Rob my rider had a good look at the sytem, the baffle was terrible, and internally were all the pipes are let into the collector nothing was finished properly with ends all bashing together. just stuffed in and welded.
Rob spent a lot of time fettling this area, because we thought the system should work. the baffle was left out because it was useless and we would have needed to make something suitable if the system proved to be better.
but after all this, and rejetting to suit the system gave 3hp more than our original system but this was only between the 9 to 10k rev range, the rest of the revrange was below power and less tractable.
So what was our original system based on.
??
The header pipes were an old motad 4 into 1, I heated and bent them slightly to be as close to sump as possible, and Rob did his 'special' mod to the collector as he sort of turned into a bit of an expert with the die grinder. the rest of the system was home made to be as tight to the bike as possible and to try and look a bit period as far as possible and have a 1oodb noise pass, as well as being straight thro type baffling.
The next test would be one of carpy's, or a lighter weight version of what we have. but we beat em all any way. so I suppose its not so important now.
andy