How to Install a Drag Specialties Tach on a 1500A model 

I bought a Drag Specialties Mini-Tach (DS-243910) and a Drag Specialties accessories (handle bar) clamp (DS-24380) from Sherm's Cycle Products <www.scp.com>.   

Parts List:

1. 22-gauge wire, 3 feet (and 16-gauge wire, 3 feet if you are going to use a relay)

2. Bullet-style crimp-on blue plastic coated 16-gauge wire connectors (2 sets male/female).  These are for jumping the 12V connections.  In almost all cases, modification is needed which is described later.

3. Spade style crimp-on blue 16-gauge (blue plastic coated) wire connectors (2 sets male/female).

4. Wire butt connector blue plastic coated 16-gauge (1)

5. OPTIONAL. Solder and solder gun, if you decide to use bare aluminum connectors and want to solder the wires to the connectors.

6. OPTIONAL. Some clear silicone to apply to soldered wires.

7. OPTIONAL. Wire shrink-wrap (12 inches 3/8th inch) to cover soldered wires.

8. OPTIONAL. Automotive relay available at any auto parts store (i.e., AutoZone, NAPA, etc.).

Along with the Drag Specialties accessories clamp, I used a right-angle bracket (from an old tail light relocation kit) to attach the tach to my left RISER (5 ½” X 4 ½”). This keeps the tach low and to the left of the console so I can easily see the idiot and turn signal lights.  This was my personal preference.  The (shorter) stock risers are not long enough to accommodate the clamp.

THE TACH WIRING SET-UP

The tach itself has four wires: 

Ø       RED and BLUE for powering the tach’s electronics, and tach light.  Both wires can be twisted together and connected to one positive current source); 

Ø       A BLACK wire that goes to ground, 

Ø       A GREEN wire that attaches to one ignition coil to pick-up firing signals. 

HOW TO CONNECT THE TACH TO THE COILS

You'll need extra (22 gauge) wire to lengthen the GREEN wire to reach the ignition coils, which are located behind the engine’s rear cylinder.  To connect/splice the tach’s GREEN wire and the wire extension together, strip the two wires, twist them together, solder them, and cover the solder with shrink-wrap.  A faster solution is to use an insulated crimp-on butt connector and some shrink-wrap over the butt connector.  Pliers will do a good job crimping the butt connector, but a $10.00 wire stripping and crimping tool will do the best job since it has crimp positions for plain or insulated connectors, by wire size. 

Remove the gas tank to give yourself more room to run the extended tach GREEN wire from the handlebars and along the frame to the coils.  Make sure to run the GREEN wire (without an end connector) through the existing frame plastic electrical wire-ties, and have a few more plastic wire-ties on hand in case the wire droops on anything hot (i.e., engine cylinder) that can melt the wire insulation.  Once the wire is strung to the coils, you can crimp-on an appropriate connector on the end of the GREEN wire.

The 1500A/B 1995 KAW service manual wiring diagrams doesn't clearly label which wire is negative on the coils. KAW Tech Support confirmed the negative wire colors on each coil: 

ü       Front cylinder coil #1 - black (BK) wire 

ü       Rear cylinder coil #2 - black/green (BK/G) wire 

are the NEGATIVE wires.  Connect the GREEN wire to either coil’s negative spade connector.  

TECH NOTE: Our BUBF’s and the other Vulcan 1500 bikes use a double-fire ignition system, similar to what Harley’s uses.  This means a spark is fired in BOTH cylinders each time either cylinder is at/near Top Dead Center (TDC). So it makes no difference which coil the tach’s GREEN wire is attached to.  The tach is designed to sense every ignition firing. 

TECH TIP: Since Sherm’s told me that Drag Specialties has a factory-made "Y" connector that connects to both coils I bought one. The connector is well made with in-line diodes to prevent signals going from one coil to the other.  It's well worth the money, but NOT absolutely needed.

The standard DS "Y" coil connector ends that go over the negative

coil terminals are round “O” (probably an H-D accommodation for their ignition coil design), but I needed to get the round connector on the BUBF coil male spade (tab) connectors.  So I used a pair of pliers to gently squeeze and shape the round connectors into elongated "slots" that just fit over the negative coil tabs, and then pushed the negative wire female connector over the tab to hold the slotted tach connector in place. Shaping the original round connectors into slots, saves you having to cut the round ends off and putting on new ones.  I also put a little dielectric grease on the connectors to reduce possible corrosion, and insuring a better long-term electrical connection. 

Again, if you are not using the DS Y connector, you can connect the GREEN wire to either coil’s negative post (either coil, your choice).

POWERING THE TACH USING THE BIKE CIRCUITS

After you have the tach's GREEN wire connected to the coils, you then need to provide electrical power to operate the tach's electronics, and light the tach face so it can be easily seen at night.

Your best bet is to connect the tach’s RED and BLUE wires to a power source controlled by your ignition key so the tach is powered/activated only when you have the ignition key turned ON.  The tach’s RED and BLUE positive pair can be spliced to the BROWN or WHITE positive ignition wires (not recommended); or spliced into a running light wire such as the BLUE wire in either of the front turn signal/running light harnesses.  The BLACK ground wire can be spliced into any BLACK or BLACK/YELLOW ground wire including the BLACK wire in the turn signal harness, or connected to a frame or engine ground bolt. 

Another choice is take power from the accessory positive (WHITE/BLUE) and negative/ground (YELLOW/BLACK) lines in the headlight nacelle, but the positive line is ALWAYS hot or ON, even when the ignition key is turned off.  As a result, you would need a means of turning off accessory power to the tach when you were away from the bike.  If you use a manual switch, it leaves open the possibility of your forgetting to turn off the tach switch and having the tach slowly run the battery down.  It would take a while to totally drain the battery, but if you left the switch ON over the weekend without riding the bike to recharge the battery, you would very likely need a jump.  As described later, a relay activated by the ignition switch is a good way to access and control accessory lines.  More on this later.

WIRING TECHNIQUES FOR CONNECTING THE TACH’S POSITIVE AND GROUND WIRES TO THE BIKE CIRCUITS

Patching in the wires is nothing more than placing the tach’s positive and negative stripped wire ends into the bike’s positive and negative opened bullet or block connector, and then squeezing the connector closed over the extra wire.  Needless to say this is very crude and subject to problems if the wires come loose, and is not recommended for long-term use.  But this is a good method for quickly testing the unit and wiring during installation.

Tapping (or splicing) into a bike line is a process of scraping wire off the bikes positive and ground wires, twisting the tach’s positive and negative wires in place over the respective exposed wire, and soldering the wires together.  Then cover the splice with silicone and electrical tape, and/or shrink-wrap.  You would then use a spade connector male/female set between the bike’s tapped wires and tach wires.  Needless to say, this “pig tail” is a permanent connection needing a bit of work to install the wire.  But it is effective, and will do the job.

TECH TIP:  With a BIC lighter, heat the insulation to soften it before you scrape it back.  The job will go faster.  Gunslinger, Martinsville, VA.

Jumping in the tach wires is making a “V” shaped wire with the appropriate electrical connector at the three ends, that allow you to open one of the bike’s bullet or spade connectors and connect the jumper wire between the stock connectors, and then connect the tach’s positive (or negative) wire to the third connector.  It takes a little time to make the “V” jumper, but it’s a clean solution that’s easily to remove if you decide to stop using the tach, or if you need to test the circuit without the tach attached.  This is the method I recommend.  CLICK HERE TO READ HOW TO MAKE A JUMPER WIRE

Now on the tach wiring ends, crimp-on a female spade connector on the twisted-together RED and BLUE wire pair, and crimp-on a male spade connector on the tach BLACK ground wire.  Open the BLUE running light wire bullet connector and connect its male/female halves to a "Y" jumper's female/male connectors.  Then connect the RED and BLUE tach power wire pair's spade connector to the "Y" jumper spade connector.  Do the same to JUMPER into the bike's BLACK ground wire with the other “Y” jumper.  You should now be able to switch on the ignition and have the tach's face background light go on.  Then start the engine. The tach's indicator needle should immediately indicate the engine’s RPM’s.

Bottom line, the tach is great, and can be installed quickly and correctly. The initial process took me 4-5 hours. Knowing what wires to use, the whole connection installation process should take less than one hour, with all the wires made-up in advance.

TROUBLE SHOOTING:

1.  Misconnecting wires.  Always follow your service manual's wiring diagram color codes.  Anyone trying to wire up anything without the diagram is in for a lot of extra work.  You'll blow fuses and perhaps damage that new meter or light bar.

2.  Grounding.  I've learned that any time you can ground a meter, light, or relay to the bike frame and stay away from the bike's ground wiring, you get better results.  Using the bike's ground wires can create voltage drops that then create weird combinations of some lights working, while others don't.

Manjo ~V~1111 1500A9

USING A RELAY TO ACCESS AND CONTROL ACCESSORY LEADS

I had a different situation with my bike since I had two gauges I was adding to the bike, and I was planning to add at least one more gauge in the future.  So I needed a power source with a fuse that could handle the extra load, and reduce the electrical load on the stock lighting circuits.  I decided to take power from the accessory lines in the headlight nacelle.  This circuit has it's own 10 amp fuse.  The problem was the accessory lines are ALWAYS hot (flow current), even if the ignition switch is turned OFF.

So the solution was to use a RELAY.  A relay is smart enough and cheap enough (~$4.00) to allow current to flow only when it is "activated", and could flow 10 or more amps to the accessories or gauges I wanted to use.   Click here if you want to read how a relay works.  

I used the same front-right turn signal running BLUE (positive) wire as used above to power the tach, to now control activating/deactivating the relay switch. In this way, current would go to the tach (and an additional volt/amp gauge) ONLY when current flowed through the BLUE wire when the ignition switch is turned ON. 

I also chose to use jumper wires to connect the relay and tach to the bike's circuits instead of cutting and splicing.  I wanted to be able to easily remove all connections to the tach and relay if I needed to test the circuit without their load on the circuit.   

You can make your own wires for this project.  The relay coil-side jumpers have a male or a female bullet connector on each end, and a male spade connector on the other. 

You will need to read about making small bullet connectors (CLICK HERE), and then RETURN/continue here.

I crimped and shrink-wrapped the connectors to the three ends. In my case, I needed bullet male/female connectors for the Blue running light wires and a female spade connector to go to the relay.  The positive accessory wire to the relay switch input side is one piece of 16-gauge wire with a male spade connector to the accessory positive wire, and a female spade connector to the relay.  Connect the tach positive wires (RED and BLUE wires twisted together and crimped into a female spade connector) to the relay positive output male spade connector.  The relay and the BUBF circuits you use may require different connector types.  Crimp a male spade connector to the tach’s BLACK ground wire and connect it to the accessory negative or ground wire. 

Now when you turn on the ignition, you will hear a "Click". This is the relay switch snapping closed and completing the circuit to pass current to the tach.  You should also see the background light on the tach face go on.  Start the engine and the tack should show the bike’s rpm’s.

The relay switch tabs to flow power to the tach itself, have the positive accessory wire feeding into one switch tab of the relay. The other relay post has a wire to the combined red and blue positive wires of the tach. The tach's black or ground wire is then connected to the accessory black/yellow ground wire. It's a simple set-up.

ALL YOU NEED TO KNOW ABOUT RELAYS

You use a relay for two things:  to use a thin and cheaper wire to control the on/off flow of high current through a thicker more expensive wire, thereby reducing the amount of high cost thicker wire needed for the bike circuit.  OR, to turn a current flow on and off that is normally always ON.  

TECH NOTE: KAW uses a relay on the starter system to start/stop the flow of current from the battery to the starter motor through heavy 6 and 8 gauge battery and starter motor cables.  When you press down on your bike's starter button that uses 16 gauge wire to connect to the starter relay (which is only live when your ignition key is in the ON position), the starter relay "closes" and high current flows to the starter motor (through the shorter heavy gauge wires) that turns your engine crankshaft until you release the starter button.

In the case of adding gauges that are powered by the accessory power leads in the headlight nacelle (there's another set of leads under the rider seat), you use a relay to both access and automatically CONTROL the 10 amps current.  Why?  Because the accessory power leads are ALWAY hot or on, even when the ignition switch is OFF.  You would use a relay to turn the accessory current ON and OFF with your ignition key.  In a tach application, a ~$4.00 automotive relay will do the job well and for small dollars.  

HOW DOES A RELAY WORK? 

Embedded in a relay are two parts: a coil and a switch that's closed by the coil. The coil becomes magnetized when current flows though it, and the switch is pulled closed by the magnetized coil allowing current to flow through the switch to the accessory.  A ~$4.00 automotive relay is an epoxy "brick" about 1" x 1" x 1" with several connectors sticking out of one side.  Most relays have four (4) male spade connectors.  Some have a 5th post which is an extra power-out connector and is not discussed here.

The 4 posts work as two pairs.  A pair is connected to each end of the coil, and the other pair is connected to each end of the switch.  There's usually a simple schematic printed on the side of the relay showing which posts are connected to the coil side, and which post are connected to the switch side.    

EXAMPLE: Adding a gauge to your bike powered by the accessory lines.

You would connect the "coil" side of the relay in line to a wire that only flows current when the bike's ignition key is in the start position.  A convenient wire to use is the BLUE front-right (or left) turn signal running light wire.

You would then connect the "switch" side of the relay to the positive power source, which is the positive accessory lead wire (WHITE/ORANGE).  You would then connect the positive wire from the tach to the other relay "switch" connector.

Lastly, you would connect the tach's negative or ground wire to the accessory ground wire (BLACK/YELLOW).

So when you switch ON your ignition key, power flows to the tach.  When you turn your ignition key OFF, power stops flowing to the tach.

MAKING “V” JUMPERS

My thanks to Ernie v1667 for this great idea. You make a "V" shaped wire jumper connector by removing about a 3/8 inch of insulation from the ends of two 2 ½ to 3 inch pieces of 16 gauge wire. Put one end of both wires into a single male 16-gauge bullet connector and crimp it closed. Be aware of the following.  The stock front turn signal BLUE and BLACK/YELLOW wire bullet connectors are smaller than any I could find, so I modified the smallest (.156 inch diameter) bullet connectors that I could easily find at any automotive, Radio Shack, or hardware store, by cutting way at the metal seam on each connector and squeezing the sides together to make smaller diameter bullet connector pairs for the “Y” jumper wires. 

THE SMALL KAWASAKI BULLET CONNECTORS

Kawasaki uses an unusually small bullet connector for many of the BUBF wire connections.  The connector is 2.5MM (0.10 inches) in diameter, whereas most of the bullet connectors you’ll find in auto and electronics stores are 4MM (.156 inches) in diameter.

The 4MM bullet connectors come in two types or shapes:

1.        The true bullet or rounded-end connector.

2.        The open-ended or conical-end connector, which is better of the two designs for this application.

In either case, they can be made smaller by cutting out material along the seam that runs the length of each connector.  Use a Dremel tool with a fiberglass-cutting wheel at ¾ speed to cut away about 1/8^th inch of material from the seam.  After each cut, use a pair of pliers to squeeze the connector closed, then measure.  You’ll do this two to three times until the connector fits the mating Kawasaki connector.

(NOTE: If you can find the smaller bullets, buy them, and immediately let me know where you bought them so I can tell everybody else).