How to wire up a Tachometer to an 85, HELP

[Dabble Inn]

Has anyone been successful?

I posted up the wire diagram and believe it should be wired to the green coming off the coil to the solenoid, well that did nothing. So tried the orange between the coil and igniter, it did get a signal from there but the needle was all over the place willy nilly. Only time it was steady was 2500 at full throttle lol and 5500 at starting lol.......

One thing I found that might be a problem is at wfo top rpm the battery voltage went as high as 15.8v, but that doesn't explain the low rpm inaccuracy when it's still in the 12v range....

I'd like to try an inductive pickup style tach (clamps directly to the spark plug wire) but can't seem to find one that is analog with a pedestal mount for the steering column, I don't want a digital readout tach. Trying to stay in the old school hot rod era of the 60's-70's theme

[raydhd]

The Equus 8068 fits the bill. I have one on both the VC 460 and the sled engine carts. Also had it on the stock HD engine (briefly) until I blew the fan apart @ 6500 rpms.

[cart around]

Interesting that one of the reviews on the summit website mentions connecting it to the negative side of a standard coil or an inductive pickup. That might answer the question on how to hook up the one you have.

[raydhd]

I used a Sunpro super tach iii that I had wired off the neg coil on the HD stocker. Worked great there. Then switched it to the VC 460's kill wire. For awhile it worked great there. THEN I started getting wild fluctuations all over the rpm scale. I tried all kinds of things trying to get to work like it first did. I never did figure out why it worked for several weeks great and then started reading all over the place. In the end just bit the bullet and bought the Equus. Worked great right off the bat. When I built the HD with the sled engine I just bought an Equus right off the get go. And again it work right off the bat.

[Dabble Inn]

To CA;
The one I bought says connect the pickup wire (coincidentally also green) to the neg side of coil too, but I was confused as to which one that might be on our coils. Since we have a green and orange coming out of the coil I was leaning towards the green, especially since the orange comes from the igniter but the green didn't do anything....

I should add;
Before I started I first took a test light to each wire off the coil and cranked it over to see which one had a pulse. Well, silly me it turns over a bit too fast to really tell lol. Kinda thought I saw some fluctuation in the green wire though so that's why I chose it first.......

To raydhd;
I'll look into the 8068, this is the one I bought and returning (Equus 6078 3-3/8" Bezel Tachometer, Chrome). Think I'm down to an induction clamp on the plug wire now....

To both of you;
Another complication I had to think about, rethink and probably overthunk it a bit was 2cycle vs 4cycle and what will actually work. My final conclusion is using a 4cycle tach on a 4cylinder setting should be the ticket, why you ask?

Ok it's like this and please correct me if I'm wrong, a 4cycle 4cylinder engine should produce 2 pulses per rev. Right? (I know the old school with distributor does). Well, I figure these single cylinder 2cycle Ezgo's with electronic ignition also produce 2 pulses per rev... Since the flywheel has two 'points' for pickup to the pulser roughly about 40*-50*ish apart, one each for timing (forward & reverse) then it should produce two sparks per rev. right ??

Thanks to you both

[raydhd]

In more simple thinking with the plug induction firing be it 2 or 4 cycle or one or 12 cylinders the plug itself only fires either one every revolution or once every other revolution where as coil firing can be much more complex

[Dabble Inn]

Uh oh, think I over thunk that idea too dang it. A 4cycle tach won't work if I set it to 'plug wire' induction no matter how many cylinders it has, the tach would expect 1 pulse every 2 revs. I need a tach that receives 2 pulses every 1 rev, Ughhh!!

However;
Your last post actually simplified the more complex thinking of coil wire induction LOL.....I think

Pretty sure the tachs that have an induction clamp feature have the option of 'coil' wire or 'plug' wire, I'm now thinking the coil wire setting is the only way to make it work. Since I believe it's getting 2 pulses per rev then set a 4cycle tach on 4cylinder on coil wire setting but yet clamp it on the plug wire, Huh? Huh? Hmmmm, why why why does my brain hurt

[raydhd]

The Equus can be set to read from 1 to 12 cylinders. Take a look at their site for all the install options. Pretty sure with the 8086 there is an option that will work for you. The only NoNo I found is DO NOT CUT the plug impulse wire. I did and everything I tried there did not work. Luckily the sell just the plug impulse wire for people like me that didn't believe the instructions warning.

[Dabble Inn]

I looked at the Equus site and boy that ain't an easy one to navigate, some of the tachs offer a pdf download for install instructions but the ones I think might work did not offer that dang it. I figure I'll need about 6' of pulse wire to reach, if ya can't cut it ya probably can't add to it either... I'm stubborn so I'll keep looking around a bit more before I give up, Thanks

[raydhd]

One other thought would be a Harley dual fire unit such as I use on my ironhead sportster. Both plugs fire from a single coil even though they need triggering at different times.