Quote:
Originally Posted by herr_oberst
10 to 1 on pump gas? Is that stock or did you bump it up? If you bumped it up what sort of ignition upgrades do you do to keep it from detonating?
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Stock is 9:1, so yes, I did bump it up a point. The only ignition upgrades are a breakerless replacement for the points and a high energy coil. Timing is set at 35 degrees total, coming in at 1,800 rpm. You essentially don't run these things much below 3,000 rpm, so it's really running at full advance if it's running at all. It retards to about 10 degrees at idle, and to make it easier to kick.
Some guys like to twin plug these things. I'm a big believer in twin plugging our 911 motors (my 3.0 liter MFI motor runs an Electromotive crank fired twin plug setup). Old Harleys are a different animal, though. Extremely undersquare motors - this one is 3 3/16" bore by 3 13/16" stroke. So, a second plug would not be all that far away from the first one, and the first one gets exposed to the whole combustion chamber relatively early on the (long) combustion stroke. There really does not seem to be any advantage to twin plugging a street motor in this compression range. Kinda counter-intuitive to everything we "know" from our 911 motors.