Flame thrower

Mightyboosh · Jul 19, 2012

I want to give this a try. My idea is to come out of the CDI with spark plug wire to a switch, and from the switch two sp wires one to the engine and one to a spark plug in the end of the muffler.
I think im going to have to make the switch. I dont think the switch needs to be too complicated. something that is normally closed and i can press the button and it bumps the conductor to the other spark plug.

Anyone know what this kind of button is called? or am i talking nonsense.
p.s. I can accept blowing a old motor in the name fun with fire.

locell · Jul 19, 2012

Mightyboosh said:
I want to give this a try. My idea is to come out of the CDI with spark plug wire to a switch, and from the switch two sp wires one to the engine and one to a spark plug in the end of the muffler.
I think im going to have to make the switch. I dont think the switch needs to be too complicated. something that is normally closed and i can press the button and it bumps the conductor to the other spark plug.

Anyone know what this kind of button is called? or am i talking nonsense.
p.s. I can accept blowing a old motor in the name fun with fire.

are you thinking of something like a horn button? I've seen those labeled as "momentary switches"

Greybeard · Jul 20, 2012

http://www.amazon.com/dp/B0068TSC1G...and=598224929618841050&hvpone=&hvptwo=&hvqmt=

It's been a while, but I believe you need this type of switch.

leaded50 · Jul 21, 2012

...and here locell is quite near the optimal idea! Put in a pump who could spray into the end of the exhaust pipe, trough a near flat pressed tube, or as used in procars, a injection nozzle. Use a diesel glowplug to fire it up! But all this need some electrical.......

No raw gas extra in cylinder,no ignition changes, and the engine running giving the exhaust pressure to "throw the flames out" the exhaust pipe, without backfire.

Allen_Wrench · Jul 21, 2012

This is just a hunch (and I'm not really TRYING to be a stick in the mud) but something tells me that if one of us actually gets a flamethrower working on his motorbike, it'll become so problematic that the novelty will wear off real quick. Just to make one semi-reliable could prove costly, not to mention the unwanted (law-enforcement) attention it's likely to attract.

Greybeard · Jul 21, 2012

When I said "
BTW. I've never heard of any type of engine problems associated with flamethrowers, but a few mufflers have suffered."

dragray said:
yes, there have been engine troubles related to this type of flame thrower.
when you use it, you're washing the cylinder(s) down with raw gas which washes oil away.

dragray said:
why is it that whenever someone posts something about a problem, there's always someone who has to come back and say "no, you're wrong!"

Yep, you are so right. There is always somebody telling us that we're wrong and giving anecdotal evidence about some "friend" that had a problem.

If used with common sense, the chances are slim that your 4 stroke engine will suffer damage, and virtually no chance a two stroke would be damaged no matter how you use it. Looking at u-tube vids of flamethrowers I see people that are probably pulling out the choke to increase the amount of fuel in the system. The flames that are short and white, or blue white are made with a proper mixture. The big, lazy, yellow flames are done by adding additional fuel, and if that is done by pulling out the choke and pumping the throttle, you are indeed washing the cylinder walls down, and common sense says that aint good.
I built my first one years before dragray was born, and drove that old car to school for 3 years before I replaced it.

There are dozens of manufacturors of flamethrower kits. The street rod industry is huge, as is the sharing of information. They couldn'd survive as vendors if their products were known to cause engine failures.

wayne z · Jul 21, 2012

Mightyboosh said:
I want to give this a try. My idea is to come out of the CDI with spark plug wire to a switch, and from the switch two sp wires one to the engine and one to a spark plug in the end of the muffler.
I think im going to have to make the switch. I dont think the switch needs to be too complicated. something that is normally closed and i can press the button and it bumps the conductor to the other spark plug.

Anyone know what this kind of button is called? or am i talking nonsense.
p.s. I can accept blowing a old motor in the name fun with fire.

There is no standard or normal type switch that will do what you want. The high voltage will just arc thru the switch when it's open.

You might be able to fab a knife type switch to do that.

There is a special switch that is made to do that though. They were produced for the experimental aircraft guys. They sometimes convert auto engines for their planes, and they used this high tension switch to enable them to have a second ignition coil for backup , with only one set of plugs and one distributor.

Mightyboosh · Jul 21, 2012

wayne z said:
There is no standard or normal type switch that will do what you want. The high voltage will just arc thru the switch when it's open.

You might be able to fab a knife type switch to do that.

There is a special switch that is made to do that though. They were produced for the experimental aircraft guys. They sometimes convert auto engines for their planes, and they used this high tension switch to enable them to have a second ignition coil for backup , with only one set of plugs and one distributor.

Yep you hit it on the head. I had it all together, took off down the road popped the clutch and i had arcing all over the switch. I bought a switch from radio shack, the biggest one they had. A toggle ON--OFF--ON. The power was too much. Im thinking another CDI is needed and I need to have the switch between the engine and the two CDI's. The CDI is what steps up the current right? I think the switch will be able to handle the current coming form the engine.

I think the best set-up would be to have a CDI with a switch in it. If anyone knows anything about that id like to hear about it.

george_n_texas · Jul 21, 2012

I know a buddy of mine used to turn the key off on his car for about 2 seconds and when it turned back on it made a huge BOOM! I imagine if you were to get goin 30 MPH and held the kill switch when it fired back up would likely do the same thing...I'm between builds so I can't test this.

Mightyboosh · Jul 21, 2012

I know looks like a third grader drew this, but is this what you are talking about when you say knife button? where can I find copper sheets at?

Mightyboosh · Jul 21, 2012

george_n_texas said:
I know a buddy of mine used to turn the key off on his car for about 2 seconds and when it turned back on it made a huge BOOM! I imagine if you were to get goin 30 MPH and held the kill switch when it fired back up would likely do the same thing...I'm between builds so I can't test this.

I think this will cause ignition to high in the exhaust pipe.

wayne z · Jul 22, 2012

Mightyboosh said:
I know looks like a third grader drew this, but is this what you are talking about when you say knife button? where can I find copper sheets at?

A knife switch is just a short piece of bar copper, with an insulated handle on the end, attached to a terminal bracket with one screw that it pivots on. the contact is just 2 pieces of copper mounted together with another terminal conection, and when you close the switch it knifes between them to make contact.
Look at an older type fuse box or electrial disconnect for 110-220 power, to get the details.

Mightyboosh · Jul 22, 2012

Like what you would see in the old cartoons? would that split the power or send it to to the 2nd plug only.
Do you mean like this? It would look cool. steam punk.

Mightyboosh · Jul 22, 2012

Never mind about spiting the power i figured that out while drawing it.

Greybeard · Jul 23, 2012

The wire that energies the CDI, isn't that the one you put the stop switch in? Does anyone know what the voltage is?

locell · Jul 23, 2012

george_n_texas said:
I know a buddy of mine used to turn the key off on his car for about 2 seconds and when it turned back on it made a huge BOOM! I imagine if you were to get goin 30 MPH and held the kill switch when it fired back up would likely do the same thing...I'm between builds so I can't test this.

was this a mid 80's model subaru by chance?

Mightyboosh · Jul 23, 2012

I'm trying with my china girl right now. Might try on the 99cc predator later.

george_n_texas · Jul 23, 2012

locell said:
was this a mid 80's model subaru by chance?

Nope it was like a 60 something Mustang convertable I think it was back in the early 70's. Funny you should mention 80's Suburu I had a wagon replaced the tranny engine pretty much everything over the years I had it man was that a tough car!

locell · Jul 23, 2012

george_n_texas said:
Nope it was like a 60 something Mustang convertable I think it was back in the early 70's. Funny you should mention 80's Suburu I had a wagon replaced the tranny engine pretty much everything over the years I had it man was that a tough car!

ya those things are solid, i had a friend that would turn off the key, pump the gas a few time, turn the key back on and BOOM it was louder than a pistol shot. I thought that was an exclusive feature to the 1985 Subaru GL, now i know better

Lil bobber · Jul 23, 2012

Mightyboosh said:
I'm trying with my china girl right now. Might try on the 99cc predator later.

Kool... Keep us up with the progress!

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