a while ago i was at a popular bike meeting place, Rivington Barn, Rivington UK.

i remember seeing two guys with diffrent twins both spitting flames as they revved there bikes. it looked evil!

one was the VTR Firestorm and the other a TL1000 the one that resembles a gixxer not the naked looking other.

is this done by simply having racing exhausts?

if not how it is done?

is there any pros / cons to this?

does this cause any damage to the engine or other parts?

 

ok, I'm gonna regurgitate what has been told to me by mechanics and friends. if you disagree, what else is new? this is a bike forum. here we go: open pipes, with no baffles will allow for flame spitting. my buddy says my hawk does it too. I've got leo vince's with the baffles out. then tune your bike slightly rich, combined with big jugs, and lotsa gas anyway(these are carburated twins here) all you're seeing is gas that doesn't burn off till its coming out the back. just extra gas cooking off. it will not cause mechanical damage , it is nothing to worry about. you see race bikes on tv doing it all the time. I guess a con would be: you're just so cool that the girls are too scared to ride your pyro-spitting freighttrain from hell. thats about it. oh, and mine has been spitting a little flame for over a year now, and no issues yet.

 

good question. I know lots on here have their bikes spit out on decel.

 

If I'm not mistaken, that's what the PAIR system on the bike is supposed to prevent. It allows air into the header so that unburnt fuel dumped upon sudden deceleration will burn in the header and not be expelled into the air. With the PAIR system removed or disabled, and the bike running rich you could get enough unburned fuel through the exhaust that it ignites when it hits the muffler and the relatively "fresh" air just beyond the exhaust tips. Check out some of the WSBK bikes and you'll see it, especially Haga's Yamaha last year. There are tons of pics of him mid-corner with fire coming out of his pipes.

It won't cause any problems since the gasses burn off so quickly that you shouldn't have to worry about the heat.

 

My chopper has been throwing flames for 2 years with no problems.


Excuse my ignorance, but what does PAIR stand for?

 

My '86 CB700SC Nighthawk S with a full stainless 4 into 1 Supertrapp would spit flames occasionally during the 1-2 upshift.

It all has to do with how rich the mixture and open the exhaust is. Won't happen on a VTR with stock baffled cans.

 

[QUOTE=
Excuse my ignorance, but what does PAIR stand for?[/QUOTE]

Pulse Air, it's a form of exhaust emission control which burns excess hydrocarbons (unburned gas) as they exit the combustion chamber by adding air to the hot exhaust.

 

here is my ducati monster

http://s251.photobucket.com/albums/g...t=SANY0682.flv

TURN IT UP