Introduction: Installing a SPY 5000 Two-way Motorcycle Alarm Into a Honda 1998 CB250 Nighthawk

This Instructable describes the installation of a SPY5000 two way motorcycle alarm with a Honda 1998 CB250 Nighthawk motorcycle.

This Alarm is rather typical of after-market motorcycle/ scooter alarms available all over the world. My installation was not standard, and was more complicated than I expected, so I am sharing my experiences and knowledge  to possibly assist anyone else who finds themselves in a similar situation. I have found previous guides lacking some of the finer detail which may be required, so I have included as much information as possible to hopefully aid the reader.

Step 1: Tools & Equipment

SPY 5000m motorcycle kit
CB250 Nighthawk
Electrical Schematic for both kit and bike
soldering iron & solder
electrical tape
cutters , screwdriver socket set, scissors
Automotive Relay SPST and Cradle
Automotive Relay SPDT
3 x 1N4004 Diodes
1 x BD681 Darlington Transistor
1 x 68kOhm Resistor
Spade Terminals and Spade Lugs
Multimeter for continuity/voltage

Step 2: Alarm and Wiring Description

The Spy 5000m is a generic alarm and required modification to suit the CB250 Nighthawk. As you can see in the alarm schematic, there are  many wires which leave the “Brain” plug, and interface with the bike’s wiring. I shall go through each one in turn.

   This wire doesn’t actually go through a removeable plug/socket, it comes directly out of the Brain box. I placed my antenna behind the rear light assembly inside the bike, as this area is mostly plastic, and it is close to the Brain Box, which is seated in the rear storage compartment.

Red Wire:
   This is the power supply to the BrainBox. There is an inline fuse on both sides of the plug/socket, and the manual says to wire it to the battery. I chose to wire it to the fused side of the CB250 power supply, by tapping into the bikes RED (R ) wire after the bikes Main 20A Fuse.

Brown Wire:
   This is the wire which connects to the CB250 ACC (Accessory) Wire, which is Black (B) in colour. When the Ignition Switch is on, the ACC line has +12V on it, and supplies power to lights, indicators, horn, e.t.c.
     When the remote start feature is turned on, the ignition is off, so the Spy5000 feeds +12V into the ACC wire through the Brown (Br) wire.

Pink & Grey Wires:
    I will describe these two wires together as they are linked. These wires are part of the Ignition Kill circuit. The instructions say to CUT the Black/White (B/W) wire from the ignition key switch and connect the Pink wire to the Ignition Switch SIDE of the cut, and connect the Grey wire to the other cut B/W end. Then the SPY5000 can kill the ignition.

                      (I will explain this later)

Blue Wire:
   This wire connects to the Starter Motor Start Wire which is Yellow with Red (Y/R) and allows the SPY5000 to turn the motor over when the remote start feature is selected.

Yellow & Yellow Wires:
   These 2 wires connect to the Orange (O) and Sky Blue (Sb) Indicator wires, and allow the SPY5000 to control the  indicators, front, back and on the display panel.

LED Indicator:
  This pair of wires does not go through the 9 pin plug/socket, it has it’s own 2 pin socket. Basically a blue indicator light that flashes to let  people know your bike has an alarm.

    This is the earth wire and does not use the 9 pin plug/socket. Must be grounded for SPY5000 to operate properly.

     This is very loud, I left it disconnected until final checking of the system. Ear Plugs are recommended.

Microwave Detector:
    This is a little control box with a sensitivity adjustment trimpot on it. I haven’t decided where to put it yet, but it is NOT WEATHERPROOF, and would require protection on the CB250

Note the Wiring Diagram has a 9 pin plug with 10 wires coming out of it. The Antenna and LED have their own connections. Only 8 wires are used with the 9 pin plug.

Step 3: Problems : Modification #1

    My CB250 has a CDI (Capacitive Discharge Ignition). The kill switch and the ignition switch stop the CDI by grounding the Black/White (B/W) wire to Earth. If the B/W is not grounded, the CDI continues and the ignition will continue to spark. The B/W has a voltage potential ranging up to 140V derived from the CDI unit. Be careful, it will tickle you if touched when the engine is running.

            Inside the Brain Box, there is a relay, which is Normally Closed (N/C) Its connects to the Pink and Grey wires.

            When the SPY5000 disables the ignition, that relay inside the Brain box activates, and it disconnects Pink from Grey, when the contacts open. This action will have no useful effect on the B/W wire. To stop the CDI, it must ground the B/W wire to earth.

            So I had to find a way to convert the N/C contacts to trigger the B/W to earth.

        This circuit uses a BD681 Darlington transistor to turn on a diode-protected Relay. The Relay Earths a B/W wire from the CDI when the transistor is triggered. The Transistor is held LOW and OFF when the pink and grey wires are shorted together through the SPY5000’s internal Relay. When the SPY5000 activates the Ignition-kill Relay, Pink and Grey are disconnected from each other, allowing the BD681 Base (B) voltage to rise and turn on the Relay.

Step 4: Problems : Modification #1 .. Cont

Small Boring Maths Part. (skip if you want)

The 12V Automotive Relay has a coil resistance is 87 Ohms.
As I = V/R (Ohms Law), the current it draws when ON = 12/87 A = 138mA or 140mA rounded up

The BD681 has a Hfe (gain) of 750, therefore the Base current required to switch this load
Ib = 0.14A / 750 = 0.187mA

The Size of the Resistor required to limit current flow to 0.187mA over a 12V potential =
R = V/I = 12 V / 0.000187A = 64171 Ohms = 64kOhms. This gives me the resistor value to use.

Note this circuit connects to 12V from the battery, so it will draw 0.000187A per hour in standby state. This is equal to
4.488 mA / day , Or 31.4 mA / week , Or 125.6 mA / month.

Lower power consumption levels could be obtained if a transistor with a higher gain Hfe was used, but this is quite low already.

So this module when built has 5 wires leading into it.

1. Pink Wire  --> goes to Brain Box Pink
2. Grey Wire  --> goes to Brain Box Grey
3. +12V          --> goes to Brain Box Red
4. Ground     --> goes to Earth
5. Black Wire --> goes to the B/W wire in CB250

Step 5: Problems : Modification #2

 As mentioned earlier, when the Ignition key is “OFF”, the CDI unit is earthed via B/W wire through ignition switch and then to ground via Dark Green wire (Dg).

When Remote Start feature is activated, the SPY5000 sends +12V through it’s Brown (ACC) wire and then sends a brief +12V signal through Blue (into Y/R) to the starter motor circuit. This should start the motor, except the CDI unit is still earthed through the Ignition Switch, which is in the OFF position.  The Ignition cannot spark, the bike cannot start. This is the problem.

Therefore, I have added a Relay which is triggered by the SPY5000 Brown Wire +12VSignal and it cuts the Earth (Dg) wire from the Ignition Switch and ONLY the Ignition Switch.

This involves wiring up a diode protected relay, triggered by the SPY5000 Brown Wire. The unique Dg wire from the Ignition Switch was then identified , disconnected from the other Dg wiring, and re-routed via it’s own wire to the relay, which switches it back to earth. The picture shows multiple Dg wires crimped together. The correct wire must be located, disconnected and it’s new extended wire run to the Relay.

Step 6: Problems : Modification #2 ... Cont...

    This relay should only be triggered by the SPY5000’s ACC circuit, not the CB250’s ACC circuit. A 1N4004 diode placed between Brown and Black ensures only the SPY5000’s ACC circuit will  trigger the relay.

    Without the diode, the CB250’s circuit could trigger the relay, then the ignition switch may not stop the CDI when the key is “OFF”

   This is how the Relay is wired up. You have the Brown ACC feed, the Dg wire from IGNition, and the Earth Wires. Note you will need a Relay with a N/C terminal and the protection diode as well.

    So,  when the bike is started normally with the Ignition Key, this relay is off and Normally closed, the circuit performs normally.

   When the bike is “OFF” and the SPY5000 starts the bike remotely, the SPY5000 ACC wire (brown) goes +12V, turning on the relay, disconnecting the Ignition Key from Earth, enabling the CDI to operate. When the SPY5000 turns off the bike remotely, the relay closes, the CDI earths via Ignition Switch and Relay Contacts.

Step 7: Assembly

   Because there is not enough free space behind the headlight, and there is no space under the seat where the battery/fuses/ starter circuits / relays are, I have installed the SPY5000 in the rear compartment, behind the rear brake light.

I have added the Dg wire from the front of the wiring loom to the existing wiring loom.
I have created another small alarm loom which runs parallel with the existing loom and carries wires from the centre of the bike back to the rear compartment.
I have added spade terminal connectors into the bike’s wiring loom, splicing into the existing wires so the alarm can be removed easily if it malfunctions.

There is an image of added connectors. It shows the RED wire , Blue, Brown wires from the SPY5000, connecting with the Red, Y/R and Black Wires on the CB250. The Grey wire connects from the Relay in Modification #1 to the CDI B/W wire.

Step 8: Assembly Cont..

This picture shows the indicator connectors, spliced into the CB250’s wiring harness, one blue and one orange . These connect to the Yellow Wires from the SPY5000 Brain Box

After all connections are made, the SPY5000 loom was wrapped in electrical tape (Nippon Denso) and run parallel with the existing loom. Secured with tape and the occasional zip-tie, the alarm is installed and concealed from curious eyes and fingers.

In order to access all electrical parts, the seat, side panels and fuel tank were all removed. The headlight was removed to expose the circuitry and to locate the Dg wire specific to the Ignition switch.

Unnecessary for installation but useful to know, the Ignition Switch B/W wire and the Kill-Switch B/W wire both join in the wiring loom, next to the Left Hand Ignition Coil, under the fuel tank. This position was explored when following the original instructions, but is not required.

The Ignition Switch Dg wire and the Kill-Switch Dg wires join together in the main loom inside the headlight housing, and it is in this location that the Dg wire was cut for the Ignition Switch , and an extension added and routed all the way to the Relay in Modification #2 (labeled IGN in the Picture) This is the only wire that requires cutting in this installation. The others are spliced, and there are many ways of doing that. I chose soldering and heat-shrinking where possible, or just soldering and taping.
Regarding earthing, I chose the central rear bolt outside the rear compartment as an earth point. It secures the seat release mechanism, and I scratched the paint off the chassis under the bolt head to ensure good earth contact.

Step 9: Observations

Initially I thought this would be a simple 2 hour installation. The circuit diagram was simple to understand, the colours matched my bike’s colours and it made sense. So I hooked it up as the diagram said. After it was hooked up, there were 2 problems.

1.         The Ignition kill feature did not work. Perhaps with a bike with a positive feed system it would. That’s what Modification #1 was for. If the SPY had a relay a SPDT relay instead of a SPST relay, then my modification would have been unnessary.

2.         The Remote start would not work, because the  Ignition switch in the OFF position shorts out the CDI. That’s what Modification #2 was for.

Now with the two modifications, it all works 100% .

 I have noticed other installation guides and a lot of people only have partial success with their installations. Disabled ignitions, disabled kill switches, features un-useable because things are not understood, blown fuses, flattened batteries, burnt wires, damaged components. I think someone would have to be very lucky to find a generic alarm which matches their motorcycle perfectly. Or pay a fortune to an installer to avoid the hassles and headaches which can be created by D.I.Y.

With my installation, the Kill Switch works regardless of Manual Start or Remote start. If you leave the kill switch ON, the bike won’t start.
With this installation, the motor CAN NOT START in Gear, unless you are holding down the clutch handle.
With this installation, the motor WILL NOT START in Gear with the Side Kick Stand down, just like it was designed to do.
It will start in Neutral with SideStand down, manually or remotely.
It will start in Gear, remotely with the clutch handle in, but what’s the point of that ?

I’ve read about so many people who have installed DIY alarms and have lost functionality on their bikes, making them dangerous and sometimes easier to steal. That is something I don’t want or need.

This concludes the Installation report. If there’s any areas I haven’t covered in enough detail, or if you want clarification or photos, let me know and I’ll see what I can do. Thankyou for taking the time to read this, hopefully if may help to avoid pitfalls and complications for you too.

©  2011
All Pictures taken by me except for Alarm wiring diagram taken from Users Guide, and Honda CB250 wiring diagram (c) from CLYMER Nighthawk Manual