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1982 CM450A...horn works in low, but not high
Posted: Fri Jun 13, 2008 4:38 am
by dweiss
So my bike is now 95% restored. I have one small glitch that even my Clymer book can't help me with.
While in gear, my horn will work in low. As soon as I click up to the high gear, the horn does not work.
Suggestions?
Posted: Fri Jun 13, 2008 5:10 am
by storysunfolding
that doesn't make sense to me at all. The gear shift is independent of the horn circuit. Is your charging system ok? It may be that in a higher gear you're staying in lower rpms and the battery is getting drained... only thing I can think of... maybe a bad horn?
Posted: Fri Jun 13, 2008 5:38 am
by fireguzzi
Maybe just a bad connection? The higher speeds maybe shakin something loose.
Posted: Fri Jun 13, 2008 6:52 am
by dweiss
I know that the horn is good, I did the Clymer test that has you disconnect the horn wires and attach them to a 12V battery. The horn sounds good and strong.
I do have a feeling that it has to do with RPM's...but I have no clue how to address that. My carbs are balanced, and the bike runs VERY smooth, so I don't want to alter RPM's just to make the horn work in high (above 45mph).
I haven't detected any other electrical issues, so I don't think it is a charging issue...but, I am a newbie.
Any other thoughts? My mechanic, who is a Honda classic bike certified mechanic, jokingly says I have a ghost in my bike.
Thanks for all the responses so far...
Posted: Fri Jun 13, 2008 7:17 am
by dweiss
Well shoot, it can't be due to RPM's. According to my Clymer book:
"The alternator generates an alternating current (AC) which the rectifier converts to direct current (DC). The regulator maintains the voltage to the battery and load (lights, ignition, etc.) at a constant voltage regardless of variations in engine speed and load."
Okay, since low RPM will not affect electrical at this point...I'm lost.
Suggestions?
~Debbie
Posted: Fri Jun 13, 2008 9:39 am
by storysunfolding
Debbie, that assumes the alternator and rectifier are working properly. I'd follow fireguzzi's suggestion first to see if it's a bad connection in the horn circuit then go through this diagnostic
http://www.electrosport.com/technical-r ... iagram.pdf
Posted: Fri Jun 13, 2008 10:26 am
by dweiss
Will do. Thanks! You guys are great!
1982 CM450A... horn works in low, but not high
Posted: Sat Jun 21, 2008 7:13 pm
by silverwinginit
Hello DW the tbl may be fixed already but I do see a few missing facts or at least good questions not addressed... for instance...why must your bike be in gear or even motor fired up?... will the horn work if you just turn on the key?.... will the horn work when you put it in neutral?..also is the wiring harness connected to the correct circuit? not reversed in any way? also when you go to a high gear do the lights dim as well indicating a problem with the voltage out put ..hard to check by yourself but maybe you can ride behind someone who can look at your headlights while you go thru the gears...just a few ideas. Hope you fix the problem I put together a 1952 "k" model Harley from 3 boxes of parts and that included the engine timeing gears and transmission which was in the same case in those older bikes and all I had was the HD service manual to guide me so I can sympathize with your situation.

Posted: Fri Jun 27, 2008 6:55 am
by dweiss
Update...the bike was in the shop this past week, and they found a connection or two in the harness that were a little corroded. After cleaning the connections, the horn worked; with key on, with bike turned over and in any gear, etc. Thank you to everyone who responded!
~Debbie