The International CBX Owners Association

It looks like my 82 has a non working horn on the LHS. It looks to be in very good shape, but get nothing at all, no buzz, nothing, when horn button is depressed. RHS horn works no issues.
So just to be sure it's the horn itself and not the wiring, I checked continuity in the LH small wiring harness (leading from main harness to the horn connectors) and have continuity. So LH small harness is OK. Small harness shown in last pic.
I connected the LH main harness female bullet connectors and hooked to the RHS male bullet connectors. The RH horn works hooked up to the LH main harness.
So this tells me that my LH connection from the main harness and through the small harness to the LH horn are both OK.
The RH horn works when connected to the LH wiring, but the LH horn doesn't work when connected to the RHS wiring. RH horn works with RH wiring.

The horn connectors are tight and the terminals are clean. No excessive rust anywhere.
I took the large nut off the horn and I have about 3 full turns available for the center stud. Not sure what this adjustment does.
As well, there is adjustment with the small phillips screw with the small nut to put more or less pressure on the inside disc. I take it this tunes the horn.

But so far no buzz, no anything when horn button depressed.

There also are no markings to say LH or RH horn, all I can see are (MB-E Mitsuba Japan) and on the outer ring (12VH 1 8 3).
According to parts list, LH is for LOW pitch and RH is HIGH pitch. Both the LH and RH horn are two separate part numbers.
Some pics. Are there some adjustments on the horn itself that can make or break an electrical connection? Or is it the internal wiring is fried?
Can the horn be taken apart and perhaps repaired.

Before you despair, read this and see if it helps:

viewtopic.php?f=21&t=7397&p=64706

These horns have a set of 'points' inside. Check for continuity across the two external terminals - you should have it. On yours, you likely will not. There is dirt/corrosion on the points. You must take the horn apart to fix this and the late model horns are tough to get apart. It's a lot like taking the gauge bezels off, you have to pry around the crimp. You have to decide if it's worth it. I've fixed a couple and it's an easy fix once you get it apart. The early model horns are much easier as they have screws to take apart. But that's what your problem likely is.

Ironically, I didn't learn this by taking apart CBX horns, I learned on old BMW horns. They are notorious for the points losing continuity. Same for the CBX horn.

Dave

Thanks for the responses, will check it out and report.

OR --- ask Louis what a replacement might cost. usedcbxparts.com Might be worth the price!

So, spent the day pulling the horn apart. No continuity. Opening up the hem was a big effort, took about 2 hours to get it worked apart, but finally got a system that worked. I put a small socket over the center so I could clamp it in the vise. Also put some masking tape around the body but it wore off pretty quick, a paint job in order. Here's some pics. I used one small precision screwdriver to get the hem opened, then the longer one to work the hem open all around. I filed the corners and sharp edges off the larger screwdriver to mininmize damage. It started to loosen up after 1.5 hrs, notice black mark relative to connector, Used a little prybar (think its a seal puller) to work the hem open. Another half hour with the prybar, and got it to the point where a few screwdrivers worked over the edge and off comes the ring. Open ring, continued on next post.

Look at the corrosion inside. I couldn't believe it, no wonder it didn't work. Folded some 320 sandpaper and slid between contacts to clean the surface. Looks like a manufacturing issue here, points don't align very well. After a bit more clean up, I now have continuity. Little sanding and masking, ready for spray paint. First spray coat done, final tomorrow.

The gasket is in pretty poor shape, looks like a very thin, I think a fiber gasket. Thinking maybe 0.25mm max.
What did others use?

I SALUTE YOU SIR! Great repair, great tech, great post. Nice contribution too Dave.

Thanks for actually doing and especially showing that. I think you will be in business now. FWIW, the 2 horns on the late models are not the same. There are two different pitches and they have different part numbers. If sourcing a replacement, it'd be nice to know if you got the correct one.

My experience with the Pro-Links with two horns is that on many bikes, only one works and the owner just doesn't know it.

Dave

If the contacts are always made what's the reason they
are in in there?

hondaman160mph wrote: ↑

Tue Feb 02, 2021 9:37 am

If the contacts are always made what's the reason they
are in in there?

Sometimes I have a hard time understanding what someone is saying. Maybe because English is not my native language...

Ok I get it now, sorry, I haven't had my morning coffee yet. Carry on....

Nice work on fixing the horn, oldbikerdude.
Sure it is a small part but this excellent tutorial is another example of how important this site is in keeping the CBX marque alive and on the road.

Peeled the old gaskets off, they were pretty ratty.
Happened to have some paper gasket material that measured the same thickness (0.014") as the old ones I pulled off.
Cut gaskets and tacked them into place. After gaskets were in place, I fitted the stainless ring over both halves, still very loose here. Then set the assembly over the aluminum vise jaws and started with crimping the ring with a ball peen hammer, only in 3 places (120 degrees apart).
The reason for this I wanted to be sure that the two pieces were centered to each other.
I looked into the large threaded hole to see that the post from outer piece was centered in the cavity.

Before I continued I attached the horn wires to the bike, loosely adjusted the center threaded post, as well as the small screw with locknut, and what do you know the horn works, still to be fine tuned though.

Once the two pieces were relatively tight together, then started peening over the hem with a ball peen hammer.
You can see in this pic the hem is not quite closed. After the hem was mostly closed, but not 100%, I used a punch with the hammer to drive the hem closed.
Bit of a bugger hanging on to the piece with my lower palm while moving the punch slowly over the working surface of the vise. There is no way to clamp the piece into the vise, the part is just sitting loose on top of vise. Because I handled the part too soon after I gave the piece a second spray of paint first thing after I got into the garage, I dulled the paint right quick with my sticky fingers while holding and peening the hem over.
No matter, after the piece was fully hemmed over, I sanded around the dull part and covered again with masking tape and gave it another spray of paint. Final paint tomorrow, then let it dry good, and then tune it before install.