Flames out exhaust, glowing red header

[400eXr1d3rZ]

My friend just got a HMF slipon on his warrior and when he lets off the gas after revving it a blueframe shoots out the back, he said it was too rich, but I noticed his header was glowing, and I said hes too lean. Is he lean or rich? What jetting should he have, needle clip, and air/fuel screw?

[400eXr1d3rZ]

Anybody?

Look at the spark plug. It sounds to me like its too lean.

[400exrider707]

Well did he change any jetting at all when he put it on? It's lean. If its backfiring when he lets off the gas, then the mixture screw needs to be richened up. Also the pilot, and main should be raised, and the clip on the needle should be lowered (richened).

[JW450R1]

rejet your probably too lean

[400eXr1d3rZ]

He got jets, but they just came with the exhaust, he doesnt know what size they are. He never messed with the air/fuel screw, im going to call him in a little while and tell him about this. Thanks

[Cody_300ex]

Too lean, lol. Flames out of the exhaust is too rich, excess fuel coming out of the exhaust and igniting. Lean er up.

[400eXr1d3rZ]

Originally posted by Cody_300ex
Too lean, lol. Flames out of the exhaust is too rich, excess fuel coming out of the exhaust and igniting. Lean er up.

But how can it be too lean and too rich? Exhaust is flaming and the header is glowing, flames = rich, red header = lean. I don't get it.

[Cody_300ex]

Originally posted by 400eXr1d3rZ
But how can it be too lean and too rich? Exhaust is flaming and the header is glowing, flames = rich, red header = lean. I don't get it.

I was laughin because they said it was too lean, headers will glow red, period, all it means is the motor is running hot. Yes it is a common symptom of a lean condition, but thats just because a lean motors going to run Hot. I say down a size or two on the MJ.

[GPracer2500]

My guess is his pilot circuit is too lean. Flames coming out of the exhaust doesn't necessarily mean he's too rich. Flames shooting from the exhaust can be caused by being too rich OR to lean. I would think a blue flame (as oppose to yellow/orange) suggests a lean condition. Rich mixtures burn cooler (yellow/orange flames) while lean or stoich mixtures burn hotter (blue flames). But just the fact that this condition developed after adding a slip-on makes a lean condition by far the most likely.

It seems like a way too lean mixture would consume every last bit of fuel. That (incorrect) assumption causes confusion and begs the question of how a lean air/fuel mixture can create flames shooting from the exhaust. The answer: Lean mixtures burn unreliably. This causes pockets of air/fuel mixture in the combustion chamber to occasionally not burn at all. These unburned mixtures get passed out of the engine into the exhaust. As unburned fuel passes through the exhaust it will occasionally find conditions that allow it to ignite and the result is flames shooting from the exhaust.

Typically, the unburned fuel from lean missfires ignites in the headers much closer to the engine and that's what causes the "lean pop" that is so familiar. But sometimes (depending on exhaust design, the quantity of unburned fuel, and other factors) it doesn't ignite until the moment it exits the exhaust.

[400exrider707]

Originally posted by Cody_300ex
I was laughin because they said it was too lean, headers will glow red, period, all it means is the motor is running hot. Yes it is a common symptom of a lean condition, but thats just because a lean motors going to run Hot. I say down a size or two on the MJ.

A warrior stock headpipe is thick gauge steel, its not going to glow red unless its running really lean. The flames does not mean its too rich, read GP's explanation cause he can relay stuff a lot better than I can.

[400eXr1d3rZ]

So what would jetting normally be for a piped/filtered Warrior?

[400exrider707]

Not too sure what the stock jetting is so I cant really tell you. Is he running an aftermarket filter? Lid on or off?

[400eXr1d3rZ]

K&N filter and lid is on.

[400exrider707]

what brand jet kit came with the pipe? DynoJet or what? I cant remember what a warrior uses, mikuni or kehein?

[400eXr1d3rZ]

Dont know what brand jets came with it, he just bought it from eBay and used those jets. It uses Mikuni I think.

[warrior350x]

hes way too lean he should raise the main jet and lower the needle if he can and to mess around with the air/fuel screw are you sea level I had the same problem it took me time to get it right
PS> I never seen a warrior header glow hes got to be way off