just a quickie , an maybe I am nuts

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thegnu

New Member
Sep 15, 2011
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freedom pa
I had this thought today an was wondering does anyone think a 2 stroke china run rich enough to make an exhaust flame shooter ? hot rod guys been doing it for years an I have a good understanding of its components an requirements . the only other issues I have is safety an legality . maybe I'm crazy for even considering this since if the port timing is off by even a hair the motor could be a bomb. any thoughts on this guys ?
 

foundmydog

New Member
Oct 17, 2011
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South Carolina, USA
That would be a serious RED FLAG to any officer or person passing you by on the streets with seeing the fire, let alone a tank of gas above that fire!

NOT a good idea...
 

wayne z

Active Member
Dec 5, 2010
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louisiana
How do the hotrod guys do it?
Is the fuel injected into the exhaust manifold? I don't think the motor could be a "bomb" unless you fed it nitrous to the intake.

If the flames only came out the exhaust I don't think it's that dangerous if you can control it. And yourself.

I realy like this idea.

Of course you would have to use disgression about when and where to use it LOL.

I've helped put a "smoke generator" on an ultralight once. Just added a small steel tube to the exhaust manifold and plumbed it to a small garden sprayer loaded with transmisson fluid.
 

thegnu

New Member
Sep 15, 2011
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freedom pa
Its only for showing off ,bike parked an idleing , its really simple about 4 inches before the end of your exhaust pipe you add a propane injector crack the propane bottle open an you need an ignition source about 3 inches from that , theres more to it just not going into that detail , an pooff while the engine runs it blows fire . I nixed the idea simply on the basics of 2 stroke motors if your port timing is off you can detonate the motor since 2 strokes scavenge fuel into the chamber there is a breif moment when all ports are open , or iff your motor is running very rich it could ignite up the exhaust an through your motor .( DId a lil reasearch diggin .) it will work on a 4 stroke or any VALVED motor tho . AN DISSCRETION IS A MUST IF YOU HAVE THIS .
was just looking for a way to improve the wow factor . its wow enough an I will be happy there . :D
 
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2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
Old timers, hot rodders, used to install a spark plug in the tail pipe of the car. They would shut off the ignition, floor the gas pedal to get a rich mix coming through the exhaust then turn the ignition back on. The spark plug would ignite the fuel mix in the tail pipe and you'd get a bang/flame. The rat rod guys are now using propane and an ignition source such as an igniter or a spark plug. Not a good idea on a 2 stroke. You might get more bang for the buck that you want. Don't try it. I'm serious; you could really hurt yourself or anyone standing nearby.
Tom
 

Allen_Wrench

Resident Mad Scientist
Feb 6, 2010
2,784
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Indianapolis
I cannot recommend playing with fire. Yes, fire looks cool. But fire can do serious injury. Fire can catch on other things nearby. Fire is problematic, and potentially lethal. It does its best work inside your cylinder, and some of our most experienced MBers bend over backwards tweaking their engines to control how long that fire stays in there to do its work.
You really don't want it dancing around outside. Trust me.
 

BarelyAWake

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Jul 21, 2009
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Maine
Old timers, hot rodders, used to install a spark plug in the tail pipe of the car. They would shut off the ignition, floor the gas pedal to get a rich mix coming through the exhaust then turn the ignition back on. The spark plug would ignite the fuel mix in the tail pipe and you'd get a bang/flame. The rat rod guys are now using propane and an ignition source such as an igniter or a spark plug. Not a good idea on a 2 stroke. You might get more bang for the buck that you want. Don't try it. I'm serious; you could really hurt yourself or anyone standing nearby.
Tom
This is true & it is definitely dangerous no matter how it's done... and I'm not recommending it w/these lil china engines (poor/shoddy construction & tailpipe WAY too close to fuel & rider), but jus' as a BTW - the slight refinement used in some show vehicles built for this is a manually activated choke (fuel source & regulation) and a switched, secondary ignition system with the spark plug installed near the end of the exhaust (as mentioned) - the manual choke allows somewhat more controlled mixes, bursts and duration of burn. The propane variant is just terrifying TBH (flame amount & backblow potential).

Thing is even aside from the obvious hazards, I always thought it looked... odd. Sure, fire is cool lookin' but srsly, if a vehicle is doing that it can only mean one of two things, it's equipped as a show queen for bling's sake alone or something is seriously wrong with that engine heh Nothin' wrong w/show builds ofc & to each their own, but as I prefer equipment/mods to do somethin' a bit more than just lookin' cool - my first reaction is always "wha? o_O busticated lol" :p
 

leaded50

New Member
Oct 29, 2011
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Norway
Chanches for blowing up the engine + are big....but so are the showfactor too....the small 2stroke engine is gonna make a blast......remember from the past when shutting ignition of ata a moped downhill, and let it suck gas as much as can....(still in gear)....then ignition on again.............blast was strong......remember one shoot the rear part of his exhaustpipe some yards......... into my front wheel......
For show,yes...but it can cost a lot in ruined parts....and the safety issue of blasting parts all over, or fire.......think over it!
 

gphil

Member
Jan 9, 2011
274
4
18
USA Georgia
389 Catalina , 3 two barrels vac had all three open up and stuck. Shut ignition off and when turned back on blew entire exhaust system off from the mufflers back. Looked like a wrecking yard underneath the car. lol Just a E-nothing in t he AF so what do ya expect. lol
 

thegnu

New Member
Sep 15, 2011
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freedom pa
YRR, thats real cool ! an certainly one I had never thought of , start the bike dissapear in smoke an ride out of it , or sit there rving the motor an make everyone "think " your smoldering the tire off it . THIS IDEA GETS A BIG OH YEAH !
Gary
 

Dan

Staff
May 25, 2008
12,765
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Moosylvania
Flame trowing faux muffler?

Or Faux jet. Either, well aft of any thing combustible. Would have great wow/goof factor.

(Dangit, now ya got me thinking! lol)
 

KCvale

Well-Known Member
Feb 28, 2010
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Phoenix,AZ
Just put a Poo-Poo long pipe on first so it's out the back, that would give you plenty of room to rig a fire display in the back of the pipe and keep it away from you and the bike.
Beside, you want it shooting out the back anyway right?
 

thegnu

New Member
Sep 15, 2011
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freedom pa
OH YEAH this is in the works ... think I may mock it up safely an run some tests at the garage if I get it working . definatly posting results