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Installing an Alarm on a CBR250...

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[align=center]Installing an Alarm on a CBR250...[/align]

Fitting the alarm is quite easy – once you’ve seen it done!
This post provides a general fitment guide to installing an alarm for a CBR250RR or CBR250R.

What you will need…
- Alarm
- Soldering iron + solder.
- Black electrical tape.
- Two O-ring terminals to connect to the battery.
- Wire cutters
- Wire strippers
- Pliers
- Small cutting knife
- Multimeter.
- Electrical Schematic of your bike.
- Dremel would be handy.

Mount the Alarm in Position…

Take off your bikes seat and rear fairings.

The first thing you must do is find a place for the alarm and secure it. You can’t cut or join any wires to the right length until it’s not going to move. Make sure the alarms speaker (big round thing) is going to get the sound out from where you put it. A bad place to put it is in the boot, where the speaker can be muffled by items in the boot and the sound is dampened by all the plastic. The alarms are usually "weatherproof", but not waterproof, so wouldn’t recommend putting it anywhere in the open (or where it is easier for a thief to get too).

Below are two pics of where I installed one on a CBR250RR. It's in the boot, but, the speaker is facing outside the boot through a hole I cut in the plastic with the dremel. The alarm was much louder here, as the sound resonates through the fairings and gets out from the bottom of the rear fairing.


If you look in the next picture, you can see the speaker poking through.


Ignition Wire…

The ignition wire is the hardest to find. It is somewhat dependant on what bike you have. The two suggestions I can provide is either getting the ignition signal from engine controller or from the rear brake switch. For the CBR250RR, the CDI wire was a Black/White wire, while the rear brake switch was a Yellow/Green wire. Use your electrical schematic to work out the best place to get the ignition wire from and its colour.

Test the ignition wire you've chosen with the multimeter to make sure its 0 volts when the ignition is off, and to the same voltage as the battery when ignition is on.

Indicator Wires…

The rear indicator wires will go up one side of the bike. Each indicator has two wires, however they may have one of them joined from each joined at some stage. Just look where the wires go to the indicators to find which wires you’ll need. For the CBR250RR, connect to the amber and light blue wire. I believe this is the same for the CBR250R, though the electrical diagram lists the light blue as "SB"... which is probably light blue hehe...

Battery Wires…

To connect to the battery, crimp O-ring terminals on the alarm ground and ignition wires and bolt to the battery terminals. Make sure to solder these wires into the O-Ring terminals to make sure they don't pull out – unless you have a proper crimping tool.


If you want to connect the immobilizer, then take this warning….
1. If your battery goes flat, you won’t be able to roll start the bike.
2. If the alarm fails, you won’t be able to start the bike.

If you still want to connect the immobilizer, then I recommend you connect it to the ignition going to the engine controller, and not the ignition wire. The wire is easier to get to, it is lower current, lower voltage and will still immobilize the bike. I put a connector on the one I fitted (hidden), so if there is a problem, I have a mating plug I keep in my jacket that will loop the immobilizer wires when connected.

Extra Tamper Sensors…

Alarms will usually have an extra ‘trigger’ wire, whereby if the wire is connected to ground (when armed) the alarm will go off. You can put several switches in parallel.

A tilt switch is a really nice addition. If someone tries to move your bike, the alarm should go off before they get it up right off the stand… and in theory, will probably drop it back on the stand and run when the alarm sounds. Some alarms have a digital tilt sensor or accelerometer… which is perfect! If not, then you can buy a tilt switch and fit yourself. You will have to do a bit of trial and error to get the angle right. Drill the holes so you can rotate the tilt switch and tighten the bolts when you find the right angle.

You can get a tilt switch with wires from Jaycar, product code SM1044 www.jaycar.com.au

A tamper switch that detects your boot being opened or your seat removed is a very good idea. For example, a thief could easily remove the riders seat without triggering the alarm, and just cutting the alarms power from the battery. Very quick to do, so a seat tamper switch is particularly important. When you get tamper switches, if your alarm requires the trigger wire to go to ground to set the alarm off (like the Cheetah alarm), then you need ‘Normally Open” type switches.

You can get a "normally open" tamper switch with wires attached from Dick Smith, product code L5240. www.dse.com.au

This is what you should have for the CBR250's



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Test the Alarm…

Test the bike alarm will go off when armed and also if you turn on the ignition when armed. Try arming and bumping the bike, though you may have to wait 5 seconds or so for the shock sensor to stabilize/enable. Your indicators should flash when you arm or disarm.

Some alarms with shock sensors can take a full minute before they reach their target sensitivity. This is so the alarm can learn the expected road vibrations and wind pressure pushing the bike around before setting the trigger point.


The alarm has a few different features, so read the instructions it comes with. It will probably take you about 3 hours to fit, first time. Make sure to tape up all the wiring too… so it’s not obvious to anyone trying to disable it. While testing, you can always shove a few rags in front of the speaker to muffle it.

If your going to leave a 250 for more than 2..3 weeks with the alarm armed, make sure the battery is charged. Any longer, get a battery tender… which is a low current battery charger you can leave connected. Never let the alarm drain your battery, as your battery will get damaged if it runs flat.

After fitting… expect yourself to forget a couple of times and set your own alarm off he he….

Hope that covers it :p

Thanks to Trigger for providing the extra pics ;)
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