toml@rlgvax.UUCP (Tom Love) (07/08/85)
i posted a query about two weeks ago regarding the installation of aftermarket
horns on motorcycles. i didn't receive much input, so i went ahead and did
it my way. this article will describe the experience of a novice electrician
(me) in doing the installation. a subsequent note may be posted summarizing
what i received via mail. other pointers have been posted directly to
net.cycle already.
note: this is oriented to toward the semi-novice, who maybe hasn't done any
(or much) work on his bike. if it's too simplistic for you, sorry.
i bought the fiamm electric horns. they can be picked up in most discount
auto parts stores and motorcycle shops, though not all the packages i saw
included the plastic-coated relay (which you need), so be careful what you get.
i paid a little over $30; this seemed to be the going price, though i have
since heard that j.c.whitney's sells comparable horns for around $15. i
didn't look into this before i bought.
i decided not to get the air horns because of concern for the compressor,
both maintenance and mounting. as it turned out, mounting the compressor
might have been a real problem on my 83 nighthawk 650, though that isn't nec-
essarily the case for other bikes.
the fiamm instructions were for the most part poor (the usual four-language
translation job), but the schematic provided most of the info i needed.
the other critical component was the schematic for my bike, contained in the
honda technical reference. as for tools, about all i used was a set of metric
combination wrenches, a phillips screwdriver, a 12v voltage tester, wire
strippers, wire cutters, needlenose pliers, and a pair of channelock pliers.
i also purchased before hand some spade connectors, male and female, and
some wire, 20 gauge, stranded. electrical tape i already had. nylon cable
ties ditto (though they're not necessary).
one thing about the fiamm schematic: it is a little overcomplicated, since it
shows a circuit which includes the old horns, with a switch selecting between
active horn sets. another thing: there are actually two schematics, depending
on how your horn button is wired. one is for a "cold" switch, where the
current goes from battery to horn to switch to ground; the other for a
"hot" switch, where the current goes battery to switch to horn to ground.
it is simple to use a voltage tester to determine if there is a potential
between the hot input on the horn and chassis ground (use the fork slider). if
there is, you have a cold switch; if not, you have a hot switch. the
tech manual schematic for your bike will tell you this too.
removing the old horns was easy; they spun off, leaving two pairs of wires,
light green (hot) and green (ground).
the first concern was mounting the fiamms. this is going to be a completely
different problem on just about every bike. my suggestion is to try to mount
the horns as similarly as possible to your old ones. i replaced the two honda
mounting brackets with the fiamm brackets, which i bent to right angles to
account for the fact that the mounting screw on the fiamms was situated
differently than that on the honda horns. this mounting provided a "ground
return" thru the frame; each horn is grounded by its mounting screw, unlike
the honda horns. the net effect of this mounting strategy was some solid,
but rather gawky looking horns sticking out a little further than i might have
liked. face it, add-on horns aren't going to be as well integrated into the
styling of your bike as the originals. you might find that you need hose
clamps, a drill (don't drill your frame), and nylon cable ties to come up
with a decent place to mount your horns on your bike.
next, the wiring. the relay is the focus for this. it requires two hot
inputs (one switched by the horn button, the other unswitched high), and
two outputs (one for the horn button circuit ground, the other for the actual
horn power). the horn button input and ground were easy; i just used the
light green and green wires from one of two original pairs of horn wires.
the power output was just two pieces of wire, one going to each horn. i
used 20 gauge because that's what i had; i've since been told that that is
too narrow a gauge, that 16 gauge is better. i used spade bit type connectors,
purchased at radio shack for a buck. the horns have male spades sticking out of
them.
now, the only part that required any semblance of intelligence; getting
the unswitched power to the relay. the unswitched power input was selected
by reading the cycle schematic to determine what the switch was sourcing its
power from - on my bike, a white & green wire. it is important that you
identify this *downstream* from the fuse, so that the horn power is fused.
the fiamms required a 16 amp fuse; my bike uses 15 amp fuses; i said "close
enough". anyway.... i pulled off enough of the stuff enclosing the fuse box
to get at the input/output wires, and found about 4 white and green wires.
by eyeballing the cable going to the horn switch i identified which wire was
the right one; a continuity meter would have been handy to verify this.
anyway, i cut into this wire, attached another 20 gauge wire to it (a T),
and wrapped the whole thing up with electrical tape. put the fuse box back
together, and all the wires were in place. used cable ties to tidy up the mess
of new and old wires.
i connected the wires to the relay (dangling loose) and punched it.
raw, headclearing noise! like a nyc taxicab, or an old pontiac station
wagon. no longer do i sound like a motorcycle; i now sound like all the
other road-groping four wheeled bulgemobiles out there, only significantly
louder!! this doesn't go beep, phfweet, bzzz, or any of those wimpy noises:
it goes HONNNNNNKKKKK, very brassy, very attention grabbing.
the last step was to securely fasten the relay, which i did using nylon
cable ties, attaching it to the bottom of the bracket the fork tubes go
through. there isn't much of any place on the frame to use on my bike;
i have an oil cooler for one thing, and also turning the handlebars to
each stop showed that there isn't much room for anything in the crease on
either side. i then shortened the wires, permanently attached spade bit
connectors, and was done.
the whole thing took me about three hours. if i had to do it again, i
could probably do it in under an hour; ie. most of that time was spent
putzing around, making sure i wasn't going to electocute the cat or whatever.
the end result is better than expected, sound-wise (though sounding like
a car still freaks me out); and about what i expected, appearance-wise (a C+
esthetically). i saved about ten bucks over the price of original equipment
horns which weren't as loud and only lasted two years.
well, if you've stayed with me this far - that's it. good luck. i'd be
curious to hear from someone using the fiamm air horns, just out of curiosity.
anyone with questions, i'll be glad to try to help.
arrive alive.
tom love
computer consoles inc - office systems group
reston, va (703)648-3300
{seismo | allegra | ihnp4} !rlgvax!toml