Flaimin HMF

[redexrider4290]

when i put my HMF on it was at night i noticed that when i hit the gas a 6 inch blue flame shot out the back, it stoped when i put the qiute core in but i think im going to take it out again

so is this flame bad? does anyone elses pipe do this

[jak1389]

i would think its not a good thing. i would say mostlikely your jetting is off.

[JDiablo]

this usually happens when your jetting is off most likely,you arent running a high octane gas are you?

[rippin2]

Happened on my dale..nothign big get the jetting right....

[2004exrider]

when i put mine on i didnt rejet that moment i took it down my yard and it would shoot out a flame when i let off, i put it in and it didnt do it after that.

[bakeen]

Sounds like the jetting is still off. Some unburned fuel is getting into the exhaust pipe. Does the engine studder at any point throughout the powerband?

[bigbadbrad]

sounds like your to rich to me

[2muchquad]

sounds like your too lean,make sure you dont have any exhaust leaks as well.

[honda400ex2003]

I know a warrior that shoots flames with a cobra on it. It also has 6" flames when he lets off the gas. I would think it is the jetting. He says it has been like that for a long time. The warrior is a '96 and has had the cobra on it just about that long. It is still running. Just alittle more info though. I would still check the jetting though. Steve

[Ridin' Jesse]

sounds pretty sweet to me!:D j/j...but really haha yeah its probably your jetting

[Rico]

Your running a lean condition, not good on a motor.

[omaits]

I actually have no idea how this could happen but, picture this...

What if his exhaust valve was open during the "down" stroke? Wouldn't that cause the flame to shoot out of the exhaust? It would also cuase some serious power loss. Is this possible?

Or, is it a jetting issue because unspent fuel is being sent out of the exhaust?

[Rico]

If you added an exhaust and didn't rejet your allowing more air thru which is a lean condition, which in turn will cause your motor to run MUCH hotter.

[bwamos]

They are correct the flame is caused by your jetting being off. Either rich or Lean (Probably lean).

Rich you have extra unburned hot fuel that couldnt ignite because there's no oxygen left. When it hits the oxygen it ignites.

Lean you have extremly extremly hot unused oxygen (because theres more oxygen than there is fuel to burn). This oxygen when hitting the air will ignite other gasses natuarly in the air (hydrogen etc.)

Lean is very very bad! theoretical optimum is 14.7:1 oxygen/fuel ratio (I think) you want to run between 13.5:1 and 14:1 so your engine doesn't burn up. (golden brown plugs)

Left over oxygen will find "something" to burn, its not picky it's just hungry. If theres no fuel it will burn metal (your valves, cylinder, etc.). That's why your plugs turn white. Metal burns much hotter than gasoline... so the Heat is actually a byproduct of the damage.. not what's causing the damage.

But, "where theres smoke theres fire." ;)

[omaits]

Thank you for that explanation. That makes perfect sense.