What actually causes kick back?

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I have run points ever since I got my 73 850 (2 plus years), rode a lot, and never really experienced kick back. Now I have switched to a Pazon, timed it at 32 degrees advance at 4000 rpm, and it runs great but all of a sudden, I'm experiencing kick back. Just trying to sort this out. Thanks.
 

ILLF8ED

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If you're referring to the kick start lever kick back, ignition before top dead center is what causes the piston to go in reverse. Either the spark is causing this or other "pre-ignition" condition will cause it.
 
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ASSUMING low battery voltage isn't an issue (points don't care about it, systems like the Boyer are extremely sensitive to it; don't know about the Pazon):

As noted, it is caused by the fact that ignition occurs (spark) before TDC and throws the piston in the opposite direction. If ignition occurs extremely close to, or at, or after TDC, this will not happen. Note that for normal running, the spark has to occur before TDC but you want the starting advance to be as little as possible. If you set the max advance on the Pazon to 28, I'd bet the kickback will disappear because that will retard the start rpm spark (move it toward TDC) by the same 4 degrees. Do the specs for the Pazon call for setting it at 32 degrees of max advance?
 
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Hi Yellow,

The Sure-Fire claims to operate down to 8 volts, so a bad battery is not likely to be the problem, but is worth a check. The Pazon advance curve for Norton calls for a timing setting of 31 degrees at 5000 rpm, or 28 degrees at 3000 rpm ( a more managable engine speed), so you may be a tad too advanced.
 
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Well, you guys are right. I should have been at 30 degrees instead of 32. I was going on a club ride and no time to strobe it so I moved the ignition plate what looked like one degree (which their book says translated into 2 degrees) and that fixed it. I had no kick back and it ran just fine. Thanks for the help.
 
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