Wiring Horn Button for Ignition Kill/Interrupt

Has anyone done this? Any ideas on how to wire it up?

This is for my 77 KZ1000. I would like to set up the horn button so I can just preload the shifter, tap the button and kill power momentarily for clutchless shifting.

Chopping the throttle a little bit has been working so far but it is kind of inconsistent.

Can't afford an air shifter setup yet either.

im sure lou can do a fine picture of it

There are many ways to do it. Here's the crudest way, but simplest way I can think of.

Make sure your condensers are tip top shape or you can end up arcing the horn button shut.

This will cause poping in the exhaust, but if you hold it too long, you will get a massive backfire.

Clutchless shifting has to be done very precisely every time or you will eventually start rounding off the gear dogs.

Pop away.

loudhvx wrote:

There are many ways to do it. Here's the crudest way, but simplest way I can think of.

Make sure your condensers are tip top shape or you can end up arcing the horn button shut.

This will cause poping in the exhaust, but if you hold it too long, you will get a massive backfire.

Clutchless shifting has to be done very precisely every time or you will eventually start rounding off the gear dogs.

Pop away.

Awesome, thanks man. I am currently using a similar circuit(with 600PIV diodes) to run my electronic tach, with some resistors running in parallel to each diode.

I should be able to just splice into that wire between the tach and the diode pack and just make sure that is grounds it out when I hit the horn, right?

Also running a Dyna S, so no worries about the condensers.

I was worried that there was some problem I wasn't seeing with killing the coils with a ground, since the factory kill switch totally cuts power to the coils.

What do you use to draw your circuit diagrams? I use to use a program in highschool that let you construct and then run electronic circuits right on the computer. Took electronics for 4 years at a vocation-tech highschool, but I'm pretty rusty as I have been programming since then. :blush:

tachrev wrote:

Awesome, thanks man. I am currently using a similar circuit(with 600PIV diodes) to run my electronic tach, with some resistors running in parallel to each diode.

I should be able to just splice into that wire between the tach and the diode pack and just make sure that is grounds it out when I hit the horn, right?

Also running a Dyna S, so no worries about the condensers.

I was worried that there was some problem I wasn't seeing with killing the coils with a ground, since the factory kill switch totally cuts power to the coils.

What do you use to draw your circuit diagrams? I use to use a program in highschool that let you construct and then run electronic circuits right on the computer. Took electronics for 4 years at a vocation-tech highschool, but I'm pretty rusty as I have been programming since then. :blush:

Uh oh, NOW you mention the Dyna S? :ohmy:

No worries. It really doesn't change much. Does the resistor/tach portion look like the way you have it hooked up with the diodes?
That is, with the resistor connected to ground.
What size resistor are you using?

Make sure those diodes can handle 6 amps for sure. Especially if you are using 3-ohm coils. Actually it would be better if you can get 10 amp, 1000v diodes. That way you won't melt them if you hold the button down for a full second. Keep that horn button clean or it will get hot and melt shut. Keep button time to a minimum.

I use plain, old, cheap-bastard MSpaint because it's free and it's everywhere. Plus it's more flexible in case I want to add photos or get silly. I haven't tried any other circuit drawing program, though.

You may be thinking of Pspice, or Spice. That's been around even since I was in school. I've worked with others who used it to check circuits I've created. Sometimes the program predicts correctly, and sometimes it was way off. Not worth the effort, for me, since I'm going to breadboard it anyway.

Sorry I left that out. Dyna S and Dyna green coils.
Here's the circuit I used:



I used 005 diodes(600PIV) instead of 007's(1000PIV)...it has worked fine up to 10K rpm so far, for a few weeks.

The resistors are 100K.

Should I be worried about running it this way?

If your circuit for the tach works, then I would keep it. However, you will need additional diodes for the kill button. The 1n4005 and 1n4007 are only 1 amp, and I would only use them to safely handle .5 amp.

Ignore the Homer drawing and add your circuit to the circuit I show on the first drawing.

loudhvx wrote:

If your circuit for the tach works, then I would keep it. However, you will need additional diodes for the kill button. The 1n4005 and 1n4007 are only 1 amp, and I would only use them to safely handle .5 amp.

Ignore the Homer drawing and add your circuit to the circuit I show on the first drawing.

Ok, will do as soon as I get some higher amp diodes.

Thanks for the help.

This can be done with a simple five pin, single contact, Bosch automotive relay. The horn button will be conected to the ground pole of the relay, therefore no high voltage will be going through the button. You can buy a relay for $4-$5 at any auto parts store.

Relay Poles:
#85 - 12 volts in from coil power wire.
#86 - Ground wire (from horn button)
#30 - 12 volts in from coil power wire.
#87a - Power out to the coils.
PS- sorry for the quick drawing!

kzz1p wrote:

This can be done with a simple five pin, single contact, Bosch automotive relay. The horn button will be conected to the ground pole of the relay, therefore no high voltage will be going through the button. You can buy a relay for $4-$5 at any auto parts store.

Relay Poles:
#85 - 12 volts in from coil power wire.
#86 - Ground wire (from horn button)
#30 - 12 volts in from coil power wire.
#87a - Power out to the coils.
PS- sorry for the quick drawing!

The problem with this design is that it interrupts coil current. This can cause spark plug firing at the wrong time. The moment of firing will be random and could be early enough to cause detonation. It could even fire when the intake valve is open thus backfiring through the carb... not good.

Also there will be arcing on the 87a contact a very high percentage of the time since the coils are an inductive load and any interrupt will likely happen during the dwell period. This will lead to arcing in the relay.

It is better to disable the firing by continuing the coil current to ground. Because the Dyna S has over 300 degrees of dwell, it is far more unlikely that you would let off the horn button right when the Dyna was trying to fire the coils. (It would only happen roughly 5 to 10 percent of the time.) Not only that, but any spark induced by the button will be delayed, rather than too early, thus preventing detonation.

Either way will experience backfiring in the exhaust.

However, a relay system could be devised to emulate what the horn button is doing. I would prefer a solid state solution without moving parts and no arcing. Not too difficult if you don't mind wiring up some transistors.

loudhvx wrote:

kzz1p wrote:

This can be done with a simple five pin, single contact, Bosch automotive relay. The horn button will be conected to the ground pole of the relay, therefore no high voltage will be going through the button. You can buy a relay for $4-$5 at any auto parts store.

Relay Poles:
#85 - 12 volts in from coil power wire.
#86 - Ground wire (from horn button)
#30 - 12 volts in from coil power wire.
#87a - Power out to the coils.
PS- sorry for the quick drawing!

The problem with this design is that it interrupts coil current. This can cause spark plug firing at the wrong time. The moment of firing will be random and could be early enough to cause detonation. It could even fire when the intake valve is open thus backfiring through the carb... not good.

Also there will be arcing on the 87a contact a very high percentage of the time since the coils are an inductive load and any interrupt will likely happen during the dwell period. This will lead to arcing in the relay.

It is better to disable the firing by continuing the coil current to ground. Because the Dyna S has over 300 degrees of dwell, it is far more unlikely that you would let off the horn button right when the Dyna was trying to fire the coils. (It would only happen roughly 5 to 10 percent of the time.) Not only that, but any spark induced by the button will be delayed, rather than too early, thus preventing detonation.

Either way will experience backfiring in the exhaust.

However, a relay system could be devised to emulate what the horn button is doing. I would prefer a solid state solution without moving parts and no arcing. Not too difficult if you don't mind wiring up some transistors.

There are alot of ways to do it. I use the one that works for me. What does the kill setup look like, for an air shifted bike without full electronics?

Do you remember the first quick shift units, that Dale Walker built?

A relay can be fired faster then, you can blink your eyes. The average, normal blink is less then 1/125 of a second. It can be fired faster then you can blink with your best reflexs.

There are alot of motors, that back fire when shifted, hit the rev limiter or spray nitrous.
It doesn't matter where you kill the power, it's when the spark is reapplied.

You can buy a relay on almost every corner in a city, you just can always find a diode when you need it.

PS- Then if you connect that relay to a simple micro switch, that is moved the shift mechanism, you have an upgrade version of the Dale Walker quick shift unit. There will be no need to think about pushing the horn button or trying to preload the gear shifter. Just hold it wide open and bang the shifter.

kzz1p wrote:

loudhvx wrote:

kzz1p wrote:

This can be done with a simple five pin, single contact, Bosch automotive relay. The horn button will be conected to the ground pole of the relay, therefore no high voltage will be going through the button. You can buy a relay for $4-$5 at any auto parts store.

Relay Poles:
#85 - 12 volts in from coil power wire.
#86 - Ground wire (from horn button)
#30 - 12 volts in from coil power wire.
#87a - Power out to the coils.
PS- sorry for the quick drawing!

The problem with this design is that it interrupts coil current. This can cause spark plug firing at the wrong time. The moment of firing will be random and could be early enough to cause detonation. It could even fire when the intake valve is open thus backfiring through the carb... not good.

Also there will be arcing on the 87a contact a very high percentage of the time since the coils are an inductive load and any interrupt will likely happen during the dwell period. This will lead to arcing in the relay.

It is better to disable the firing by continuing the coil current to ground. Because the Dyna S has over 300 degrees of dwell, it is far more unlikely that you would let off the horn button right when the Dyna was trying to fire the coils. (It would only happen roughly 5 to 10 percent of the time.) Not only that, but any spark induced by the button will be delayed, rather than too early, thus preventing detonation.

Either way will experience backfiring in the exhaust.

However, a relay system could be devised to emulate what the horn button is doing. I would prefer a solid state solution without moving parts and no arcing. Not too difficult if you don't mind wiring up some transistors.

There are alot of ways to do it. I use the one that works for me. What does the kill setup look like, for an air shifted bike without full electronics?

Do you remember the first quick shift units, that Dale Walker built?

A relay can be fired faster then, you can blink your eyes. The average, normal blink is less then 1/125 of a second. It can be fired faster then you can blink with your best reflexs.

There are alot of motors, that back fire when shifted, hit the rev limiter or spray nitrous.
It doesn't matter where you kill the power, it's when the spark is reapplied.

You can buy a relay on almost every corner in a city, you just can always find a diode when you need it.

PS- Then if you connect that relay to a simple micro switch, that is moved the shift mechanism, you have an upgrade version of the Dale Walker quick shift unit. There will be no need to think about pushing the horn button or trying to preload the gear shifter. Just hold it wide open and bang the shifter.

ive thought about that also since i dont run any extra stuff on my bars and dont really want an air shifter hanging down on side of my bike.