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Vsingle
Posted on Saturday, March 21, 2015 - 11:28 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I am curious about the exact nature of a carb backfire on a Buell Blast. What is the mode of getting the combustion process on the wrong side of the intake valve? How does that happen? Is there more than one way it occurs?
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Ezblast
Posted on Sunday, March 22, 2015 - 04:49 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Das boot!
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Vsingle
Posted on Sunday, March 22, 2015 - 06:08 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

How though? How does the burning air/fuel mixture travel backwards through the intake path? The intake valve is closed when the spark plug fires, even during full spark advance. Does the backfire ignition occur during valve overlap at the beginning of the intake stroke?
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Gearheaderiko
Posted on Sunday, March 22, 2015 - 11:34 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Uh, yes?! The backfire is not necessarily caused by spark. A "backfire" is generally an uncontrolled explosion of fuel. Better explained by someone else:
http://en.m.wikipedia.org/wiki/Engine_knocking

It could occur at any time (which technically wouldn't always be called a "backfire"). Sometimes through the carb, sometimes through the exhaust, sometimes contained in the cylinder.

When It is caused by lean fuel its because there isn't enough fuel molecules pairing up with oxygen molecules to "fire" when "asked" to. A common occurrence when the engine is cold (or "Das Boot" is bad!).
For me to try and explain engine theory beyond this is pointless. I won't do a good job and it will take forever!!
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Gearheaderiko
Posted on Sunday, March 22, 2015 - 11:39 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The above explanation hopefully answers your question about backfire when the spark is at the correct time.
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Ezblast
Posted on Monday, March 23, 2015 - 04:12 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

And still they argue. - Sigh.....
EZ
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Vsingle
Posted on Tuesday, March 24, 2015 - 02:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Who is arguing?
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Gearheaderiko
Posted on Tuesday, March 24, 2015 - 03:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

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Vsingle
Posted on Saturday, March 28, 2015 - 11:05 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Thanx 4 'splainin
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