How can I tell?????
Club Member
Joined: Jun 2007
Posts: 3,193
Likes: 7
From: North Atlanta Area, GA
Well, it doesn't really matter with the waste spark. The cylinder under a lot of pressure on the compression stroke has a high resistance seen across the electrode. The cylinder that is the "waste spark," in the exhaust stroke, has a low (relatively) resistance seen on the electrode. Don't forget that your spark plug wires have a considerably amount of resistance built into them as well (or should, especially if you have a radio or EFI). The way it's wired up is as one big coil secondary, and the two spark plug leads are both ends of the coil. It all works out.
I've heard a lot of horror stories about those Crane Hi-4 systems. I'm glad your's is working out, but for a couple years on here there were a bunch of "I got no spark, what's wrong?" threads and a disproportionate number of them were running those Crane systems, which turned out to be the cause. We've had a lot less of those threads since Crane went bankrupt. Also, any improvement you observe is more likely from timing control changes than not wasting the spark.
I've heard a lot of horror stories about those Crane Hi-4 systems. I'm glad your's is working out, but for a couple years on here there were a bunch of "I got no spark, what's wrong?" threads and a disproportionate number of them were running those Crane systems, which turned out to be the cause. We've had a lot less of those threads since Crane went bankrupt. Also, any improvement you observe is more likely from timing control changes than not wasting the spark.
I'm sure the big difference in power and acceleration is the top end job and the midrange cam my mechanic put in. Also the S&S carb really seems more reliable and consistent than that OEM monstrosity. When I first bought the bike used it seemed to backfire consistently so maybe combination of the CV carb and the double sparking ignition. It's smooth, powerful, and really pulls now in the mid range.
The main reason I got the Twin-Tec was because it has a better advance curve than the stock H-D EI module for that year, selectable advance curves, user-programmable advance curves (haven't done this cuz it requires their absurdly expensive $115 USB cable), selectable rev limit (in 100 RPM increments), single fire capability (with the SF coil I have), "multi-spark discharge" at idle (which is supposed to smooth out the idle, but with the EV-3010 cam, V&H dual exhaust, and other stuff on Bertha really hasn't seemed to make any real difference), and esoteric user-programmable functions such as rear-cylinder offset (I haven't bothered with this).
None of this gadgetry has really produced any noticeable change in Bertha's performance, though... she runs great, but she ran great before - and I'll bet I couldn't tell any real difference if I put the stock EI module and coil back on her. Oh wait, I SOLD the stock coil... NEVER MIND!
Plus, I just love having those little dials on the module to play with!
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