Introduction to installing your new LED rear light unit
The procedure is exactly the same regardless of whether you are installing a 6 or 12 volt unit and irrespective of whether the bike is wired positive or negative earth.
Installation guide contents (click to jump to a particular section):
- The tools you will need
- What’s included in the kit
- Step 1 – Removing the rear light unit from the bike
- Step 2 – Removing the old filament bulb
- Step 3 – Marking the locations for the mounting holes
- Step 4 – Drilling the mounting holes
- Step 5 – Mounting the LED light board
- Step 6 – Making the electrical connections
- Step 7 – Testing the brake and tail light functions
- Step 8 – Reassembling the Lucas light unit
- Conclusions and your comments
The tools you will need
To complete the installation of the LED rear light board you will need the following tools and equipment:
- Screwdrivers (to remove lamp unit and lens)
- Electric drill (a small pillar drill preferable)
- 3.0mm bit suitable for drilling the Lucas lamp unit
- 5.5mm (M3) spanner / socket or thin-nose pliers to tighten the mounting post nuts
- Wiring connectors (if you’re not using one of the plug-in bulb adapters)
What’s included in the kit
The various components included with the LED light board kit are as follows:
- 1x LED light board of your chosen voltage rating
- 1x bare wire connector, or 1x optional BAY15D / BA15D / BA15S bulb adapter
- 3x 3M Scotchlok solderless wiring connectors (with bare wire connector option)
- 2x 12.5mm (½”) long chromed brass M3 mounting posts
- 2x M3 screws (to attach mounting posts to the reflector of your Lucas tail lamp)
- 2x M3 insulating plastic washers (to go between the mounting post and LED light board)
- 2x M3 nuts (to secure LED light board to the mounting posts)
- 2x M3 spring locking washers (to secure screws and nuts onto mounting posts)
Step 1 – Removing the rear light unit from the bike
Removing the Lucas 564 rear lens cover
The first step is to remove the existing Lucas rear lamp assembly from the bike. This will make it much easier to drill the mounting holes and ensure that you have a neat and precise installation. Start by unscrewing the two screws which hold the outer red plastic lens in place.
With this removed, you can then unscrew the two bolts / screws which hold the rear reflector of the lamp assembly to the rear number plate. Depending upon how these are fixed it may be necessary or easier to remove the whole rear number plate from the bike first so that you also have access to the reverse side.
Step 2 – Removing the old filament bulb
Removing the old filament bulb
Next, remove the existing filament bulb from the rear lamp – you won’t be needing that anymore!
This is a good time to check that you have the appropriate adapter for the bulb fitting of your rear lamp unit.
Refer to the LED rear light connector and adapter options help page for more information on telling the different bulb fittings types apart and guidance regarding the various adapters that are available.
Step 3 – Marking the locations for the mounting holes
Aligning the mounting hole drill template
A template is provided to enable accurate positioning of the drill holes for mounting the LED light unit within the outer red lens of the Lucas 564 lamp unit. The LED light board is designed to be a tight fit within the lens so the precision is essential to making sure that it all fits back together and aligns correctly.
A PDF version of the template can be downloaded from the mounting hole templates page. Print this out at full size (100%) onto A4 paper to ensure that it comes out at the correct dimensions. As a double check, the overall light board length on the print out should measure 80 ±1mm. Cut the template out around the board outline and pierce the paper with a small hole at the centre of the two drill hole locations.
Place a length of masking tape (or low-tack sticky tape) about 3″ long across the reflector covering the bulb hole and the anticipated locations of the two mounting holes. This serves two purposes; firstly it will be easier to mark the drill locations on the the shiny reflector, and secondly it will make the surface less slippery when you come to drill the holes so that the bit does not wander off position.
Position the paper template onto the rear reflector and align it centrally so that the outer red lens fits snuggly over it. Once you have it in the right place, mark the two dill hole centres through the template onto the tape using a fine marker pen. Remove the template and confirm that the marks are centralised and level, and adjust as necessary if not.
Step 4 – Drilling the mounting holes
Drilling the two mounting holes
I prefer to use a small pillar drill to make the two mounting holes as this makes it easier to drill straight and avoid the bit wandering off.
The metal of the rear lens is only thin so you could do this with a hand-held drill, but in this case extra care will be needed and it may also be worth centre punching the locations to help make sure you drill in exactly the right place.
Both holes should be drilled with a 3.0mmm drill bit and then any swarf or rough edges carefully removed.
Step 5 – Mounting the LED light board
Mounting the new LED light board
With the two holes drilled you are then ready to install the two mounting posts which will support the LED light board at the correct height behind the red outer lens. The posts have a female thread at one end which will accept the screw through the holes you have drilled from the rear of the reflector.
Start by installing the two posts onto the reflector using the lock washers supplied. Don’t tighten them too much at this stage as some slight adjustment with alignment may be necessary. The screws will lie within the dish of the reflector plate and hence this should still lie flat against the number plate when bolted back in place.
Leaving the wiring to one side initially, offer the LED light board up to the two posts and ensure that it fits over the two protruding male threads. Screw on the two supplied nuts by hand and then offer up the outer red lens to ensure that everything is correctly aligned. Slight adjustments can be made if necessary using the slight slack in both the light board and reflector holes at each end of the mounting posts.
Step 6 – Making the electrical connections
Plugging in the LED light unit using a bulb adapter
If you have opted to use one of the bulb adapters available then this is very straightforward. Simply plug the 3-pin socket into the special terminal on the rear of the LED circuit board and ensure that this clicks securely into place. Then plug the bulb base into the socket in the Lucas lamp unit as you would do a conventional bulb. Push, twist clockwise a few degrees, then release in the usual bayonet fixing manner.
If you have chosen to use the default bare wire connector supplied with the LED light unit then this is the point that you need to make the custom connections to your bikes existing brake and tail light electrics.
Looking at the rear side of the LED light circuit board you will see that there are three electrical terminals in the special connector – the tail light supply, the brake light supply and the combined tail and brake earth connection. The central terminal of the three is the earth (marked ‘G’ or ‘GR’ for ground depending upon the model). On either side are the brake (marked ‘B’ or ‘BR’) and tail (marked ‘T’ or ‘TL’) light supplies.
3M wiring connector installation
For conciseness in this instruction guide (and because the same connectors are used in some of our other products), a separate guide to using the 3M wiring connections is provided.
Please read this guide to installing the 3M Scotchlok wiring connections before continuing.
The 3 electrical connectors on the LED light board
There is no need to worry about the polarity of the motorbike wiring as the LED light boards are designed to work with both positive and negative earth systems. Just make sure that the central ground terminal is connected to the motorbikes frame, and the two supplies are connected to the respective switches.
If you need to remove the 3-pin connector from the rear of the LED light board at any point, first lift the end of the connector upwards away from the board to release the locking tab. Don’t be tempted to remove the connector by pulling on the wires though as the terminals inside are fine and could become bent so that they no longer lock securely into place. Only pull on the plastic connector itself, or use a small flat screwdriver to gently lever this from the board.
With the electrical connections made the LED light board can then be remounted on the posts using the supplied locking washers and everything gently tightened. Two small plastic washers are supplied with the LED light kit and these should be placed onto teh mouting posts before the light board to protect against short-circuits.
Step 7 – Testing the brake and tail light functions
Testing the tail and numberplate light functions
Note that if you are using one of the plug-in bulb adapters it is necessary to ensure that the lamp unit is in contact with the motorbike’s frame or rear mudguard / numberplate to complete the earth connection. Also, the LED’s are very intense so you hould avoid looking directly at them.
Start by turning on the sidelights / headlights and confirm that the LED tail lights illuminate. The tail light function consists of four red LED’s in a diamond pattern and the three white numberplate illumination LED’s which point downwards, as shown in the photo above.
Next operate the front and rear brakes and verify that the LED brake lights illuminate. The brake lights consist of six red LED’s in a X-pattern as shown in the photo below. Note that the white numberplate LED’s won’t illuminate with the brake function, only with the tail light function when the side or headlights are on. Finally, test the tail and brake light functions at the same time.
Testing the brake light function
If either of the light functions fails to work, go back and double check all of the electrical the connections.
One possible issue you may experience is that the tail and brake light functions are reversed so that the tail lights come on when you apply the brake, and the brake lights come on when you turn on the headlights. This is due to the two power connections (the outside two on the 3-pin terminal on the rear of the LED circuit board) being around the wrong way and is easily rectified.
If you are using the standard bare wires interface, reverse the connections on the two coloured wires to swap the brake and tail lights around. If you are using the BA15D parallel pin adapter you can simply remove the adapter from the bulb socket and put in back in rotated by 180 degrees.
For installations using either the BAY15D offset pin or BA15S single contact connector this issue is very unlikely as the connections are fixed. However should this issue arrive, you can simply swap over the two outer terminals on the 3-pin plug which clips onto the rear of the circuit board. Remove the socket from the LED board and then look at the top (flat) side where you will see the three inner terminals through three slotted holes. The two outer terminals can be released from the plastic connector by gently inserting a small pin into the slotted hole to press the locking tab inwards, whilst gently pulling on the appropriate wire. Reinsert the terminals the other way round and the connections have then be reversed.
Step 8 – Reassembling the Lucas light unit
The LED light board mounted in the Lucas lens
Double check that the spring locking washers have been fitted at either end of the mounting posts to prevent the screws vibrating lose.
Also check that the two plastic insulation washers have been fitted on the rear side of the circuit board to prevent any possible short-circuits against the mounting posts.
The Lucas rear lamp unit can then be screwed back in place onto the numberplate, and the numberplate bolted back onto the rear mudguard if it was necessary to remove it for the installation. Finally the red plastic lens can be carefully positioned over the LED light board and screwed securely into place.
Just one more final check that the tail and brake lights are still working in case you have accidentally knocked a connection during reassembly, and that’s it – installation complete!
Conclusions
So that’s the installation complete and your new LED rear light board ready to give you many years of bright service. If you have any problems them please do not hesitate to get in touch using the contact form at the bottom of this page. Please make sure your email address is correct so I can get back to you.
I would also be glad to hear how you found the installation process, any problems you encountered or anything that wasn’t clear or missing from this installation guide. Please let me know how I can improve the guide by leaving me a reply via the comment form below.
[disclaimer]
I’ve run into an interesting problem. I originally wanted to use the BA15D offset pin adapter, but found that not only was the fitting very tight, it wound up twisting the contact base in the socket so the connection couldn’t be made. No worries, I had the regular connector already. I wired the 3 wires to the proper harness wires, but found that my after-market Lucas taillight with turn signals, the turn signals no longer worked. I have since found that the trouble is that the taillight housing is no longer grounded. Next is to add a ground connection to the taillight/turn signal housing to the ground wire. I hope that works.
Hi Owen. Thanks for the feedback. I’ve tested the BAY15D adapter with a range of different Lucas original and after-market lamps and it is usually a pretty good fit, but I have also come across a few repro lamps where the bulb socket isn’t perhaps as accurate as it could be. It’s rare for the bulb adapter to not fit at all though, at worst it’s usually a little tight. Sometimes the grooves for the pins aren’t as deep as they should be, so filing a little off the pins might help. I used to have a 564 tail light on my bike that I bought in India where the base contacts rotated freely and were a nightmare to align with the bulb, so maybe you have something similar.
Glad you have a solution with the bare wire connections though. You can pick up an earth point fairly easily (usually) on one of the screws on the rear of the lens unit that hold it to the number plate holder / rear mudguard.
Let me know how you get on! Regards, James
Sorry it took so long to get back to you. All sorted out, the taillight housing is now grounded to the ground wire and everything works perfectly. Bright! Shiny! Well worth it!
Glad you got the problem sorted Owen and that you are pleased with the LED light unit 🙂
Hi James
I’ve run into a slight problem. I wanted to find the solution before posting on my Lucas thread on the TRAT forum.
I found that the mounting posts interfere with the back of the light housing. My solution was to grind the surplus threads from them after the nuts were tightened. This still left a problem, as the nuts still held the board off the back. If the backing plate got tightened, it would bend the light board. The fix was a few washers. I can send a pic if I’m not explaining it clearly.
Did I miss something? Everything is installed and the light works fantastic! I just wanted to make sure I wasn’t doing something wrong.
Thanks
Hi Jay. Sorry to hear you’re having problems – I’ve responded to your message fully by email so I can include pictures. In short, it sounds like you may have fitted the mounting posts the wrong way round. They should be attached to the rear backing plate of the light unit using the screws, then the LED board fits over the protruding threads and is secured with the washers and nuts. More info in my email, please let me know how you get on and maybe send me some photos of your setup.
Regards, James
Hi James
I am looking at an Electrex unit which outputs regulated 12V a/c. As your units have the same connections -ve or +ve earth, could they accept a/c?
Steve
Hi Steve. I have never tried them with an A/C supply, but I think they should work just fine. The electronics on the board which control power to the LEDs features a diode bridge arrangement to correct against people making the connections backwards (and also to cater for both positive and negative earth bikes). This setup automatically corrects the input voltage to a D/C current of the correct polarity for the LEDs, and hence will also automatically convert your bikes A/C supply to the required D/C signal. The diodes are over-rated for the low power LEDs so I don’t envisage any problems at all, but as I say, I haven’t actually tested them with an A/C supply. Regards, James
17 caneby street
ashgrove