I just bought a 2007 wr450f great bike. The previous owner took the indicators mirror etc because he was using it off road.
However bike is road reg and I have put the rear lights indicators etc all on apart from the horn which I did connect but it not loud at all actually you can barely hear it. The factory horn is a 6volt. I did buy a new horn and that did the same. I connected the horn to a 12 volt battery and it was loud.
I REALISED that im missing the horn amplifier. I did call Yamaha dealers here in Melbourne Australia and apparently they need to order it from japan (4weeks wait). I also tested the plugs that plug into the horn to see how many volts is getting to the horn it was only 0.35 volts and I was wondering what the problem could be is it because im missing horn amplifier? is there a problem with the volts im receiving? just want to thank in advance for everyones help.