Carb backfire (lean condition) theory?
#1
Carb backfire (lean condition) theory?
I just read that a lean condition does not burn the fuel as it should, so it kind of builds up a bit and then backfires! somehow it ignites in the intake and out through the carb it goes... wtf? in my mind I can only see fire in that direction if the intake valve is open and you spark... i.e. very bad timing, or cross spark. I would think if timing was so advanced that your sparking while the intake valve is open... it would happen every stinking spark!?
My question is... how the hell does this unburnt fuel ignite in the intake??
I just had a carb backfire singe my eyebrows (i was watching the fuel from the accelerator pump, blipped the throttle a little, and POW!!! shotgun in the face!) sounds funny, but I've been battling this problem far too long... it's on the verge of kicking my ass! j/k... never happen! I've read every stinking post here on OSO, and everywhere else on the internet carb backfire was found....... in 4 languages!! Mita vittu, perkele satana helvitti!!!
My question is... how the hell does this unburnt fuel ignite in the intake??
I just had a carb backfire singe my eyebrows (i was watching the fuel from the accelerator pump, blipped the throttle a little, and POW!!! shotgun in the face!) sounds funny, but I've been battling this problem far too long... it's on the verge of kicking my ass! j/k... never happen! I've read every stinking post here on OSO, and everywhere else on the internet carb backfire was found....... in 4 languages!! Mita vittu, perkele satana helvitti!!!
#2
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Re: Carb backfire (lean condition) theory?
I know it does the same thing on a Harley if the carb is lean, pops out the carb, somene said it was because the previous combustion charge could not completely burn from lack of oxygen and when you open the throttle it corrects the needed oxygen for the still trying to burn charge and POP it burns thru the intake runner.
#3
Re: Carb backfire (lean condition) theory?
In some cases the lean mixture will cause the cylinder temp go up, and then either the hot spark plug or the exhaust valve ignites the mixture as it enters the cylinder(before the intake valve closes)-thus you get a pop.
#5
Re: Carb backfire (lean condition) theory?
The carb shop is sending two sets of Power Valves, two sets of #80 Jets and two sets of #86 Jets... I don't know what they put in to start with (I'll soon find out). Hmmm... I wonder why he's not suggesting to change accelerator pumps? I have a feeling I'm going to get to know these carbs very well!!
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07-04-2003 10:28 PM