JLO/Cuyuna Tach Install Question

[jpswift1]

Hey everyone, I just bought a new old stock Cuyuna tach for my 440 in my Attex racer and I was just wondering if someone might be able to point me in the right direction as to how to hook it up. I'm not that great with wiring, so any help would be appreciated. I won't be using the light in the tach so that isn't an issue, but the other two wires make the tach operate. There is a white wire and an orange wire. Does anyone know where to attach these on my JLO/Rockwell 440? Thanks.

[LarryW]

I dont have an idea but did a search. I found this. Maybe it will help? It came from a sled forum.

The exact wiring depends on which tach you have, but they all can be spliced into the yellow lighting coil wire, preferably as close the the motor as possible (ahead of the regulator and ignition switch).
For manual start sleds:
If you have the older round tach with the terminals marked "A,B,C,D": "A" goes to the lighting coil wire ("B" terminal on the ignition switch); "B" goes to the "L" terminal of the ignition switch or can be left unused; "C" goes to ground; "D" is not used.
If you have a slightly newer tach with terminals marked "A,Y,1,2": "A" goes to the lighting coil wire; "Y" goes to the regulator; "1" goes to "2" and then "2" goes to ground.
The little light bulb can be spliced into any of the other lighting circuit wires (usually the tail light wire).
Hope this helps!

[jpswift1]

Thanks for looking that up Larry! I think you're onto something there.......it sounds like the coil lighting wire is where the signal comes from, since the frequency that the coil fires is what determines the RPM.

[jpswift1]

I was just wondering if anyone had any updates on this. Maybe someone who has a Cuyuna engine in a snowmobile or ultralight aircraft knows something since it is basically the same engine as the JLO/Rockwell.

I was able to find the wiring for 1980-81 Cuyuna engines, but I think those were CDI, not points like my motor......hmmm still looking. Here's the link in case anyone is interested:

http://www.bayshorecad.com/Sleds/Wiring%20Diagrams.html

[Tango42]

Hey JP....I was looking thru some older posts and came across yours. I just added a tach to my superchief so I can only share what I did to hook mine up (its points too). My motor connector has 5 wires: 1 from each spark coil to shut the motor off, a ground, and 2 wires from the light or charging coil. There is a jlo wire diagram on this site that shows 2 yellow wires (the lighting coil), 2 black wires (the spark coils), and a brown wire (the ground). With the connector unplugged, check the continuity of the yellow wires from the lighting coil to the brown ground wire on the machine end of the connector (not the motor). The one that shows 0 ohms to ground is the coil ground, and the remaining one is the signal for your tach. I grabbed a tach from a 78 kawasaki snowmobile and was lucky to find a color coded wire diagram for it.....black was ground, red was signal. I ran 2 wires from the tach to the motor connector and whalla...it worked great. I'm not sure what wire is which on your tach.....maybe white ground, orange signal? I hope you are successful.....I love having a tach!

[jpswift1]

Thanks so much for that information. Once I get the motor in my new racer I'm going to see if I can get this to work. I picked up a new old stock Cuyuna tach off ebay just so I could keep an eye on my 440 when I'm racing and winding it out on the straigh-aways. I'll let you guys be sure to know how it works out.