Spark plug Gap

[shammon]

Can any one shed some light on the issue of setting the correct spark plug contact gap? Mine is to be 0.8mm is it realy important? If so whats the benifits?

[stinkwheel]

Bigger gap=higher resistance. Higher resistance means larger voltage to push the spark across the gap. This means a bigger spark.

Smaller gap = lower resistance. Lower resistance means a smaller voltage required to push the spark across. This means a smaller spark.

Too big a gap = not enough voltage to throw the spark properly. This would mean it sparking intermittantly or throwing the spark to the edge of the plug rather than across the gap to the tang. Both of which are not good.

Too small a gap = too small a spark which may not be hot enough to burn the fuel properly, the gapo could also become blocked with carbon and stop working altogether.

Too big a gap was also a good way to fry the contacts off your points back when bikes had such things.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.