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Street Twin Horn Wire Breaking

4K views 17 replies 5 participants last post by  rebel1735 
#1 ·
Few months into owning the 2016 Street Twin, one of the horn wire snapped from the base of the horn clip. The local mechanic fixed it using a different horn clip.

A few months back about 170 kms (2 hours) into a 900 km trip, the second wire also also snapped at the base of the other horn clip and on a close inspection, i realised that horn wire has become hard, presumably from the engine heat. The chap who fixed it for me said the horn wire was tight and putting strain on the horn clips.

this is happening at the place where the place where the horn wire comes out of the black jacket. was this a common issue on the older twin? it seems to be a common issue with the street twin here in India.

has anyone here also faced this issue?
 

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#2 ·
Can't see enough detail but rather than heat it looks like breaking from vibration and movement. I asume that, like all bikes, the horn is flexibly mounted, perhaps too flexibly.

Have a close look at the end of the crimped connector. You should see that they crimped the wire's insulation at the end, this ensures some strain relief. A bit like this, note the wire covering is crimped at the left side of the terminal. Can you see the remains of the plastic there?:

 
#3 ·
@Forchetto looks like I will need to cut through the plastic casing to check if the wire was crimped properly.

Fortunately I still have one of the broken horn clips around, I will cut it open later in the day and report back.

Off topic but I have also made a post in the tech forum about the front axle of the street twin your inputs regarding that would be highly appreciated.
 
#4 ·
Off topic but I have also made a post in the tech forum about the front axle of the street twin your inputs regarding that would be highly appreciated.
I've seen that post and checked the two spare axles I have in my bits box, one is for my Bonneville SE. Both perfectly smooth, round and straight, looks to be made of either a ground stock steel bar or ground after machining, so I can't add anything useful.
 
#5 ·
Copper and aluminum hardens as it is bent and moved around this is called work hardening, that would be the cause of the hard wire.

You should be able to cut back some of the wire left and strip and re connect them easily enough. i would recommend soldering them into place.
 
#6 ·
the horn on the Street Twin is flexibly mounted i.e. it can rotate / move around a bit on the securing bolt. the wire seems to be crimped properly on the horn clip i had with me, the other one was commandeered by the service chap.

while the vibration and shock definitely contributed to the wire snapping, the reasons i think that the engine heat was also a contributing factor are:

a) the chap who fixed it, could remove the insulation from the wire without applying any heat.

b) at one point when the wire broke i simply placed it on the horn clip and rode like that for about 100 kms or so without it moving / coming off, even though the road had plenty of rough patches and bumps

@Brick Bonesteel sorry for any confusion but what i meant was that the wire insulation and not the wire itself had become hard.

soldering the wire or fixing new clips on the same wire also didn't work for me, though some of the Street Twin owners here in India have done that for now, for me it kept snapping even at the base of the new horn clips.

i have gotten it fixed using a new set of horn clips and some extra wire to take of the strain, this seems to working well for now.
 

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#7 ·
Those crimped terminals look to have been correctly fitted, you can see the insulation left in them. If it happens again I'd slip a length, an inch or so, of heat-shrinkable sleeving before re-making the joint to relieve the strain and help to prevent fatigue on the end of the crimp.

Some of those crimp terminals already come with such a thing ready-fitted:

 
#10 ·
Thank you for bringing this to everyone's attention. Nothing worse than finding no horn at the very time its needed. Will go check mine.
I think the maximum heat in that area will be 100C.
boiling water. Will likely soften the original insulation or anything plastic or rubber based added. Then leaving the copper strands to suffer the load of the vibration on their own and work hardening. It might well be that the horn goes through a violent area of resonance in sympathy with the engines vibrations. Just slightly stiffer or slacker might make all the difference and probably varies from one bike to the next.
 
#12 · (Edited)
It might well be that the horn goes through a violent area of resonance in sympathy with the engines vibrations. Just slightly stiffer or slacker might make all the difference and probably varies from one bike to the next.
Great. This gives me an excuse to post one of my soporific and pedantic posts about that fascinating world of the Horn's suspension...:) Yawnnn...

For future reference for anyone contemplating changing horns, here goes a note to emphasize the importance of fitting some sort of "suspension" system to the horn. Note that some cheaper models could well not come equipped with it through sellers ignorance, or omitted due to cost of providing such a mounting.

To illustrate the need to flexiby mount electro-magnetic horns to obtain the best results in terms of sound, here are some examples of flexible mounting devices usually found on OEM and good accessory horns:



Might as well look at the Triumph one to start with:

Note this is fixed to the frame with an ordinary, thick (2.3mm) piece of normal, unyielding mild steel. This would seem to contradict things, but look further at the fixing of that strap to the body of the horn and you'll see a type of rubber mounting that allows the body of the horn to move about in sympathy with its vibration frequency, (about 500Hz).

I'll follow that with the horn(s) from my Virago XV1100. The mounting straps on these are made of a very thin and flexible spring-steel, just 0.75mm thick.

These act a bit like a leaf spring suspension and allow the horn to vibrate freely. These straps are usually doubled up, although in the case of the Yamaha there are three of them for some reason. I imagine this is to avoid fatigue breakage or something. I'm only guessing, and would welcome an engineers opinion on why this should be so.

One more example is the quality after-market horn showing once more the twin spring-steel straps it came supplied with.

It's easy to ignore this mounting technique and fabricate your own, rigid, solid mounting strap out of whatever bits of scrap steel or alloy you have lying around. The horn will work, but you'll never get the right sound from it as its designer intended.

If the horn is too solidly mounted, part of the sound will be absorbed by the mass of the frame. You could fit a long piece of ordinary steel that would allow the horn to vibrate more or less freely but the constant flexing from the weight of the horn plus its vibrations would soon fracture it.

To get an idea of how much these horns move about during operation simply hook one directly to a battery and feel it vibrating in your hand.
 
#15 ·
warranty concerns

i think soldering etc. might not play well with the warranty.

i was hoping that there would be a clip somewhere in the headlight bucket or under the tank and i could just replace the horn wire / sub harness with a better wire and insulation from thereon.
 
#18 ·
@Forchetto the bike is still at the service centre due to excessive vibration, knocking and wobble issue.

got tired of the frequent trips to the service centre and have left the bike there for them to sort it out. been about 10 days, situation is quite ****ty here. there are two service centres, one has the wheel balancing machine other has the DTI clock instrument. :mad:

currently trying to get a Triumph India Tech to have a look at the bike as the knocking issue has me worried.
 
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