Wiring Horn Button for Ignition Kill/Interrupt

PLUMMEN wrote:

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.

A simple steel collar(with a set screw) with a little tab welded to it for a lever, slipped over the shiftshaft, will bump a micro switch real nice. That will keep it on the outside of the case(I can't remember the name of the cover, behind the countershaft sprocket), and it won't get oil soaked. You will be able to lift the shifter while in 5th gear and kill the motor, you never need to take your hands off the handle bars. Then all you need, is a way to turn it on/off.(E.flasher switch, on a hidden micro on/off switch.)

kzz1p wrote:

PLUMMEN wrote:

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.

A simple steel collar(with a set screw) with a little tab welded to it for a lever, slipped over the shiftshaft, will bump a micro switch real nice. That will keep it on the outside of the case(I can't remember the name of the cover, behind the countershaft sprocket), and it won't get oil soaked. You will be able to lift the shifter while in 5th gear and kill the motor, you never need to take your hands off the handle bars. Then all you need, is a way to turn it on/off.(E.flasher switch, on a hidden micro on/off switch.)

project 34,768,000.000! :laugh:

PLUMMEN wrote:

kzz1p wrote:

PLUMMEN wrote:

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.

I'm on it!

A simple steel collar(with a set screw) with a little tab welded to it for a lever, slipped over the shiftshaft, will bump a micro switch real nice. That will keep it on the outside of the case(I can't remember the name of the cover, behind the countershaft sprocket), and it won't get oil soaked. You will be able to lift the shifter while in 5th gear and kill the motor, you never need to take your hands off the handle bars. Then all you need, is a way to turn it on/off.(E.flasher switch, on a hidden micro on/off switch.)

project 34,768,000.000! :laugh:

It's not the timing of the relay that is the problem.

It is that if you kill power to the coils, you induce a spark at the plug. This could happen any time, at any crank angle. This is very bad if you are at full throttle and you induce a spark at 90 degrees BTDC.

By disabling the ignition through shorting the coil's negative terminal to ground, you prevent any random spark from being earlier than normal spark timing. There may be a random spark when you lift off the button, but it will be after normal spark timing.

Retarded spark doesn't blow up a motor. Over-advanced spark can.

The shorting to ground method can still be done through a relay if you don't like diodes and are worried about the horn button contacts. Here, how's this?

EDIT oops wrong image

this

I figured the arcing would pit and wear out the contacts in the relay pretty quick, that's the only thing that made me leary about using one. Plus they take up more space.

Your last schematic is right on the money though, even matches the style tach I'm using.

I'll be sure to post up how it works for me, I'm going to try to head to the radio shed and see what pieces I can wrangle up.

I was thinking of trying a momentary switch on the shifter, that is disabled using the clutch safety switch. Pull the clutch: normal shift, press the shifter: clutchless shift.

You guys gotta go and get me thinking too much! :laugh:

That's an idea. An automatic disabler for normal shifting.

Anyway, any arcing in the relay will also happen at the horn button using the diode-only method. So, I don't know which will last longer. The relay would be easier to replace,though.

I went through the Radio Shack site and couldn't find any appropriate diodes for the diode method. They don't handle the curent. Try that Surge Components diode or I could look through MCM or Newark catalogs to find something appropriate if you want.

another thought, but it would require using the stock electronic ignition and my HEI mod, is I think it would be easy to devise a circuit which would simply retard the spark a lot when you hit the button. This would mean no arcing at the horn button, and would only require one or two capacitors. It would also prevent any detonation, and prevent backfiring in the exhaust. It wouldn't reduce the power the same as killing the ignition, though. I don't know if you want totally dead motor or just less power.

You'd have to have this first, though:
www.geocities.com/loudgpz/GPZgmHEImod.html

I'm either going to try the ones from Surge Components or just go the relay route. It won't see THAT much use and it will be easy to swap out as you said. Plus locally available.

The highest amp diodes Radio Shack has are the 3A 400PIV ones. I already have 4 of those that I didn't use for another project, but they don't quite cut it.

I am guessing the 4th pin on the HEI module is for cranking retard? That is an interesting idea, but I think I am going to leave that one for another time.

That 4th pin is a dwell control output. The KZ system has inherent dwell control due to the pickup design so the HEI dwell control is not needed.

Let us know how it turns out, whichever method you choose.

They say there are more then one way, to skin a cat, well I'm not into cat skinning. So here are a couple more thoughts on the subject.

The relay can be used on the coil power wire or from the ignition to the coils. You make the call!

For the weekend racers, it can be taken one step further. Now if you want to add a launch control, to the quick shift unit?

A two step rev limiter can be added to the mix. Lets say a MSD rev limiter is used. The first step is a low speed rev limiter for launching the bike. RPM is set with a chip in the control box. Then you Can set the high RPM
rev limit, to provent over reving and damaging the motor. This too is done with a rpm chip.(other systems do not use a chip, just a control knob)

This is how it works. One switch can control the quick shift unit and the launch control box.
When the clutch is pulled in and the switch is turned on,it is ready to go. The low speed rev limiter will stay engauged until the clutch is released. once it is released the low speed is turned off and the high speed limiter is engauged.
The launch control box is wired to the clutch perch (Clutch safety wires,if stock or an after market perch can be used)

At this point, what do you have?
Now with the clutch pulled in, you hold the throttle wide open, it will bump the rev limiter and the motor will misfire while holding the preset RPM limit(lets say you have it set at 6000rpms)You hear guys on new bikes, doing this all the time.

The motor is at 6000rpms and you release the clutch, now the low speed is turned off and you are on the normal rev limiter (lets say it is set at 10,500rpms)Now just bang the shifter before you hit 10,500 rpms. There will be no need to ever move your throttle hand or arm.

It can be taken, one more step further. You can add a shift light to this combo. I perfer to use a bright LED bulb in the "stoplight" on the dash.

Now you can wait for the light to come on, bang the gear shifter, while having the advantage of traction control and limiting how fast your motor will be turning.

Who knows, maybe I should of bought a Cat?