Kawasaki Vulcan Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
7,620 Posts
Discussion Starter #1
Hey,

So I've got an old Auto Meter tach sitting in my closet. I was wondering, if I set it to 4 cylinder mode, with no single fire adapter, what would my readings be like? I'm not wanting to mount it, I'm just wanting to get my idle set because I'm paranoid it's not right, it feels too high, but I also don't want it to be too low (just debaffled and it's throwing me off)

I remember on my old Cougar if I flipped it down to 4 cylinder mode I could convince people I had a souped up stock car engine under the hood turning a 5.0L V8 8k+ RPMs LOL.

So my question is, how to wire it up just to test, and, what my readings would be like. If it's cut in half, or even in a quarter, that's no big deal as it's an accurate tack. I'll just set my idle for 250rpms in that case (aka 1000rpms)

Thanks!

John
 

·
Registered
Joined
·
155 Posts
Tach help

It would show 1/4 the revolutions, unless you build your own single-fire tach adapter, in which case it would show 1/2 revs.




If you have been around a soldering iron before, you can build this for like $2 worth of parts from RadioShack/Fry's/etc in minutes.

Good luck :)
 

·
Registered
Joined
·
7,620 Posts
Discussion Starter #3
It would show 1/4 the revolutions, unless you build your own single-fire tach adapter, in which case it would show 1/2 revs.




If you have been around a soldering iron before, you can build this for like $2 worth of parts from RadioShack/Fry's/etc in minutes.

Good luck :)
Even with 1/4 revolutions it wouldn't be bad... this is just for diagnostics... not gonna mount it. Where do I hook everything up? I can figure out the hot +12v and ground pretty easy, but there is one lead that comes out that goes to the ignition, where does that attach on the 900?
 

·
Registered
Joined
·
11,756 Posts
Your Autometer should have 4 wires:

1. Tach power.
2. Coil negative ( rpm)
3. Tach ground.
4. Instrument light.

Connect 1 to coil positive.
Connect 2 to coil negative.
Connect 3 to battery ground.
Do not connect 4.
 

·
Registered
Joined
·
7,620 Posts
Discussion Starter #5
Your Autometer should have 4 wires:

1. Tach power.
2. Coil negative ( rpm)
3. Tach ground.
4. Instrument light.

Connect 1 to coil positive.
Connect 2 to coil negative.
Connect 3 to battery ground.
Do not connect 4.
Forgive my I-Don't-Know-That-I'm-Doingness, but which ones are coil positive and which ones are coil negative (on the bike?) I haven't pulled the cover off yet though, it might be extremely obvious (like a red and black wire). It's storming right now though so she's hiding under her cover :p
 

·
Registered
Joined
·
11,756 Posts
I should have said that in my first post:

Coil positive is red wire.
Coil negative is black or black/green wire depending on which coil you select
 

·
Registered
Joined
·
155 Posts
You want to attach the tach lead to one of the coil output negative wires, not the ignition...you aren't mounting it right? Ignition lead would only be to light-up the display at night.
 

·
Registered
Joined
·
7,620 Posts
Discussion Starter #8 (Edited)
You want to attach the tach lead to one of the coil output negative wires, not the ignition...you aren't mounting it right? Ignition lead would only be to light-up the display at night.
When I had it mounted on my old Cougar, it was years ago but if I remember right one wire went to a positive lead in the fuse box, one went to the dash light lead from the stereo, one to ground and one to the distributor I THINK. It's been a while, and back then I had the instructions :p

If I could figure out a way to make it read correctly and subsequently waterproof it I might just mount it in the future. Any way that's possible? It only does 4/6/8 cylinder modes so, as I understand it, my best scenario would be 1/2 the rpms with a single fire adapter right? Don't wanna mount it in that case.

Oh, and it's a Sunpro, not an autometer. Although I thought I had an autometer somewhere too... I dunno.
 

·
Registered
Joined
·
11,756 Posts
The wire that originally connected to your fuse box can go to coil positive.
Ignition lead is not for lighting.
 

·
Registered
Joined
·
7,620 Posts
Discussion Starter #10
The wire that originally connected to your fuse box can go to coil positive.
Ignition lead is not for lighting.
Yeah the lighting one is definitely all on it's own. It's a shorter wire and runs to the backlight bulb. It's dimmable and everything. Won't need that though (unless I do mount it down the road). Just wanna get my idle set.

Anyone wanna take a guess at how to maybe makeshift a way to make this tach read 100% correct? A few bucks on resistors and such would be nicer than $100 on a tach!
 

·
Registered
Joined
·
7,620 Posts
Discussion Starter #11
Okay, got it, thanks guys. Got it set for 250rpm, which should be 1000rpm right?

Hmm.. still curious as to whether or not there is a way to make it work. It'd be neat to mount it somewhere!

So I guess we have to first, mount a single-fire adapter, and then, somehow double the signal going to the tach? Is that possible?
 

·
Registered
Joined
·
11,756 Posts
It is possible, but is it practical, hmmm.
I once converted a Vega tach to read correctly for the V8 that I installed and if I remember, it was a capacitor change. But that was over 30 years ago and the memory has all but vanished.
 

·
Registered
Joined
·
7,620 Posts
Discussion Starter #13
It is possible, but is it practical, hmmm.
I once converted a Vega tach to read correctly for the V8 that I installed and if I remember, it was a capacitor change. But that was over 30 years ago and the memory has all but vanished.
Yeah...

I know nothing about this stuff I was just thinking, if it was something like a handful of stuff from radioshack and a few minutes with a soldering iron and it'd be worth it, be a heck of a lot cheaper than a $100~$200 tach. I don't want a tach enough to spend money on it but for a few bucks I'd mount this one.

Oh well. I think I'll live :p
 

·
Premium Member
Joined
·
352 Posts

·
Registered
Joined
·
7,620 Posts
Discussion Starter #15

·
Registered
Joined
·
155 Posts
Here you go:
http://www.gadgetjq.com/tach_install.htm

Provides specific instructions on how to build your own Single-Fire tach adapter with a parts list specifically for Vulcans but works on any single-fire bike.

1- foot of 18 gauge wire (any color)
2- 1N4007 Diodes (Radio Shack)
2- 100 k ohm resistors (1/2 Watt)

All that should cost you less than $5
 
1 - 16 of 16 Posts
Top