How to fit Remote Central Locking to your bike

Way back in September, while I was working my way up through France on a very sick CB250, my K100RS was nicked off the driveway. Thankfully it was found parked up on the side stand in Garden Close, Thorpe Astley, Leicester after some very lovely member of the public phoned the police three times about it.

After paying £180 for the privilege of getting my own property back (S99 of the RTRA1984 does not allow you to charge me, police!!) the poor K100 looked like this:

Very sad. The little tykes had chopped off the wiring to the ignition lock and then thrown the lock away, as well as battering the lock of the top box even though it was unlocked the whole time.. But most importantly, the indicators were still in one piece - these are now near impossible to find in decent condition. Because of this, and the fact the clutch still seemed to work, the bike was worth saving. Anyway, a quick search revealed that ignition locks don't really exist any more for these bikes, and I didn't much fancy having two keys for it. I also didn't fancy having it put back to standard trim when it is easy to steal. A plan was formed..

What I initially wanted was something like keyless ignition, where I would just have to be near the bike and it would all turn on - very sci-fi. There are many kits like this for cars but the fob has to be placed inside a little ring-shaped receiver, which is totally impractical on a bike. I turned my attention to remote blipper kits instead, not so sci-fi but more practical.. After some reading it was unclear of what exactly I needed, nonsense from poorly translated Chinese like "remote flameout" not helping, but it seemed a good idea to have remote start as it may provide a constant 12v at the press of a (remote!) button, which is what I need. Sure enough, for £10 this fabulous piece of Chinese engineering was mine:

The old Master Racing Alarm System Of Motorcycle, a classic of our time.

It's actually a neat little kit if you can put your reliability worries to one side. The instructions are, quite honestly, faintly bemusing and not helpful if you want to just use this as a remote control ignition switch.

I eventually deduced that the orange wire, the one that is supposed to bypass the original central locking circuit, provides a constant 12v which we can use to switch a big relay that can take the real load. Check it:

Knowing this, the rest is easy.

To fit this kit to your bike, you will need the following:

• A somewhat hefty relay. If your switch is a simple on/off then a simple normal relay will work, there are plenty of automotive ones out there that can switch 45A if you really must. They also often have suppressing resistors or diodes for when the magnetic field of the coil collapses when you turn it off, which can help save things (apparently). The switch on the K100 happens to connect two pairs of contacts, so I had to get a Double Pole Double Throw (DPDT) relay. I used a JQX 38F 3Z which is actually 3P3T but was readily available at a reasonable price of £5.84.
• An inline fuse holder, I bought mine from Maplin (£2.69, but not any more..) but they can be bought from Halfords for an extortionate amount or, better yet, online. Beware the mini blade fuse holder is the same physical size as the normal blade fuse holder so there is no point buying the mini one, it'll just be harder to find a replacement fuse.
• A bunch of female spade connectors, plus a wire stripping and crimping tool - these really are useful.
• Some wire, preferably black and red. This can be garnered from Halfords for a lot of money.
• Probably a multimeter so you can find a suitable feed and ground.

So, you gets yer wrecked bike..

And you pull out the bit of wiring that used to connect the ignition switch to the rest of the loom..

Strip the knackered ends off the wires and fit spade connectors so that it all snicks nicely on to your relay.

This is to bridge the contacts that the old switch would've bridged. If you didn't understand that, you may be in trouble with this job.. I also added a spade connector to the end of the orange wire of the black box and made a black ground wire for the other side of the switching circuit of the relay.

The next step is to find a power source for your new black box of remoteness. I took the opportunity to remove all the wires from the connector block that I wasn't going to use, such as wires to the indicators to make them flash with the alarm and the wire that would churn the starter with the remote start. I don't want any of that.

I eventually decided to use the +12v on the input side of the starter relay (so this is straight from the battery, basically) and a spare ground that I'm not entirely sure what its origin was. With the new Chinese box being fed straight from the battery the inline fuse was important!

With that sorted, cram it into whatever space you have. I thought the electrical gubbins box underneath the tank on the K100 would have loads of room but it was a surprisingly tight squeeze.

I also connected the speaker, not because I wanted the alarm but because I wanted the bleeps to say whether I had armed/disarmed (or enabled/disabled) the system. This fitted just nice..

And so, you end up with this.

Steal it now, tykes!! The alarm system is also surprisingly good, on the least sensitive setting I have to punch the seat to make it give some warning beeps and the wind has never set it off despite blowing the cover about.

Some people have reservations about remote blippers on bikes, stories abound of being out for a ride, needing to fill up and realising the key for the tank is at home. These people must be rather special, I just put the blipper on the keyring with the other keys. I have, however, had the lock button get pressed while the fob is in my pocket, which of course totally disabled the machine - I am now much more careful about where I put the fob in my pocket. I am also of course completely at the mercy of at least two Chinese relays but you can't spend your life worrying about that kind of thing, at least the kids can't hotwire it any more.

Satisfaction level of this job - 11/10.