I had the same problem - very weak stock horns. I pulled them off and tested them using #12 test leads straight to the battery of my truck. They worked great off the bike. So I tested the voltage to the horns while they were still off the bike - voltage was good - just a little less than the battery voltage. But when I put them back on the bike and tested voltage again - less than 10 volts. A problem in the wiring - too much voltage drop. So I re-wired some new exceptionaly load horns - using the existing horn circuit to operate a relay. Power to the horns using #12 wire w/fuse off the realy. Mounted the horns just behind the bottom fairing on each side. Now they work !!