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desertsled
08-29-2007, 05:27 PM
I am currently roadracing a 1953 Matchless G80CS (500c.c. OHV Single) and am happily running with a BSA Goldstar open reverse cone megaphone. Factory SH race cams are fitted but with this setup the bike is a bit loud (as they were back in the day)but more and more tracks are enforcing noise restrictions. I am interested in a Supertrapp megaphone as an alternative but what are my options- inlet dia. is 1.75" with outlet at 4" overall length is 13" . Would one of the universal stainless external disc pipes work and what are the decibel levels with open end caps vs. closed?

bschultz
08-30-2007, 08:14 AM
I am currently roadracing a 1953 Matchless G80CS (500c.c. OHV Single) and am happily running with a BSA Goldstar open reverse cone megaphone. Factory SH race cams are fitted but with this setup the bike is a bit loud (as they were back in the day)but more and more tracks are enforcing noise restrictions. I am interested in a Supertrapp megaphone as an alternative but what are my options- inlet dia. is 1.75" with outlet at 4" overall length is 13" . Would one of the universal stainless external disc pipes work and what are the decibel levels with open end caps vs. closed?

The Megaphone and S/C Series both come in 1.75" inlets, however are 19" and 17" in length. Another option would be the Aluminum Racing Series which has a 12" body. Db levels are hard to estimate on a machine we have never tested. I would expect high 90's with a closed end-cap and well over 100 with the open end-cap.