Mysterious Horn Problem

[WhiteMtnCruiser]

Hi,

I recently picked up a 1993 GSX600F Katana, running with only minor apparent maintenance problems but in pretty rough cosmetic shape, for real cheap. I already have my own bike but couldn't pass this one up for the price in hopes of turning it into a track bike or reselling it. The one problem I'm having is that the horn will only work when the bike is revved above 2000 or so RPM's. I just put a brand new battery in the bike and it fires right up, cranking over at a normal rate. When the key is turned and the bike is idling, pressing the horn button does nothing. As soon as the revs break about 2000ish, the horn works fine. The headlight and tailight seem to be of normal brightness and don't change in intensity when the RPM's climb. All other electrical items appear to be working fine. Any ideas as to what the problem might be?

I know this wouldn't be a concern on the track, but I'd like to be able to get it inspected and test things out on the road first.

Thanks,
WhiteMtnCruiser

[Wishbone]

if everything else works proper, disconect old wires and cap em. then run new ones off of a fused curcuit and call it a day.

[schleppy]

If I remember correctly, horns draw a decent amount of power when used, so it's possible that the bike simply isn't generating enough juice to run everything until it's spinning above 2k. As others have said, try running new wires, cleaning up ground, etc.

Maybe the rectifier is getting old and tired?

[13]

Possibly a bad ground or reg/rec. I'd put a volt meter on it, just check the voltage at idle compared to above 2000RPM.

[Josephd14]

Possibly a bad ground or reg/rec. I'd put a volt meter on it, just check the voltage at idle compared to above 2000RPM.

Been down this road before.. Bad wires, clean the contacts up good, or go the volt meter route..

[SVRACER01]

you could also try loosening that nut in the middle of the horn and then tightening it back up

[ZX-12R]

If after checking everything above you are still having problems, check the output of the stator before it reaches the reg/rect according to your shop manual. It's not uncommon for the resistance of stators to increase with age which lowers the maximum current and voltage they can deliver.

[WhiteMtnCruiser]

Thanks for the advice guys, I'll give it a try.

[Honclfibr]

As others have said it's probably a bad contact either inside the horn switch or from the horn to ground. Bad contacts can have a diode effect that avalanches once your stator is generating sufficient voltage.

I'd suggest selling the katana and buying a dedicated trackbike. Katanas aren't the best track weapons in terms of motor and suspension, and the money you can fetch now that riding season if upon us should buy a former racebike which will make a much better trackbike.

[WhiteMtnCruiser]

Yeah, I actually already sold the Katana to my brother. I currently ride an 03 SV650 and would really like to pick up a 1st or 2nd gen SV to do trackdays at NHIS. I'd go with my current bike but don't want to risk damaging my only streetbike if I go down at the track.

WhiteMtnCruiser