What can stay, what can go? Cafe racer wiring.

Hi guys,

Tore the harness out of the '81 to rebuild it after installing a PAMCO ignition and Hugh's PMA, and I had a couple of questions about what can stay and what can go.

I've scanned the forums and there's so many great diagrams there, some super simple, others much less so, but I haven't found one that matches my proposed setup.

Basically I plan to run a gel battery, electric start, head, tail and turn signals and a block of four blade fuses.

So nothing much out of the ordinary really, I just want to take out anything I don't need.

So the signal canceller is out, old alternator connections, amd ignitor unit.
Do I really need the reserve lighting unit?
And do I need to keep the safety relays if I'm running the starter?

Anything else you guys can think to ditch to keep my new harness nice and clean?

Thanks in advance guys.
And Merry Christmas!

I would reccomend using the safety relay, it protects the gears between the starter and engine from damage from the starter running after the engine starts. To do this you need to attach a yellow wire to one of the wires from the pma stator and run it to the safety relay.
On an 81 the safety relay also turns the headlight on after the engine starts. This can or can not be used. Having the headlight off while using the starter will help the bike start better.
You can just use a headlight on/off switch to do the same thing.
Any of the other devices, such as the light checker, RLU, self canceler, can be left out.
I like this diagram. It shows the basic points and seperate reg and rec of the early models. It also has the later TCI and combo reg/rec in boxes. It also has the electric starter in a box.
This will help you wire in the starter.
Use everything from the main fuse out. Wire in your PMA in as described in most of the PMA diagrams.
Your Pamco just wires in after the engine stop switch.
Wiring isn't nearly as hard as most think. Just remeber that electricity travels in circles. it flows from ther bsattery to a switch to control a device and back to the battery on the ground. If it can't get back to the battery thye device won't work.
Leo

Thanks Leo!

Great advice, great diagram.
I was mid away through photo shopping out the circuits on a colourised full wiring diagram!

I'll let you know how I go.

Thanks mate, and merry Christmas, if that's your thing!

Checking back!

Merry Xmas all!
Hope you're all as stuffed full of food and beer as i am.

Thought I'd post that photoshopped wiring diagram, which reflects the harness I've just finish putting together.

Can't test it out 'til later tomorrow, so I'm hoping for some critique in the meantime, if anyone's got the time, so my heart doesn't get broken tomorrow when she won't go!

You'll see i've swapped the connections (and names) on the ALTERNATOR and IGNITION to reflect the updated parts, and I've knocked off stuff I didn't feel i needed, including the reed switch.

Love to hear what you think.
Hope I haven't cocked it up too badly.

Thanks in advance, guys.
Enjoy the leftovers!

Looks ok. The reed switch in the speedo was used by the turn signal canceler to read distance. Deleting it and the canceler is good, they were ok when new but can and do get irratic after 30+ years.
Most people that simplify the wiring also delete the RLU. When the low beam blows out the RLU turns the highbeam on and lights the warning light to let you know the low beam is out. To delete the RLU you hook the blue/black wire from the safety relay to the yellow/blue from the dimmer switch. If rewiring just don't add all the other wiring from the RLU to the dimmer switch.
This will disable the headlight warning light on the dash and let you use it as a warning light for the charging system. I don't recall the "how to" on that. I didn't figure it out. A search will find it or maybe who ever did will read this and tell you how.
One more thing, If you replace the turn signals with most after market or led bulbs the stock flasher won't work. It needs the current draw of the stock size bulbs, 27 watts, most of the after market use 23 watt bulbs.
Using LED's for the turns your indicater won't work right. With the stock bulbs drawing as much current as they do the stock indicater works fine. With the low draw of LED's the indicater crossfeds power to both sides and all four signals flash. A bit of rewire using diodes will fix that. A search on That will get the 'How to"
Leo

Hey Leo,

How's it going?

Bit of an update for you, and a question.

Got the bike up and running, goes great! But I had to set it up a little different to how I planned due to a lack of mounting space for the extra bits.

So at the moment, i'm running kick-only with the harness i made from the diagram, plus the flasher relay (which I forgot to leave in the diagram). The RLU, safety relay and starter are just unplugged.

The bike works fine with the simple setup, with a couple exceptions.

Firstly, no headlight.
I'm wondering if
I've got one connector in the headlight bucket with nothing plugged in, that I can't locate on the wiring diagram. It's two wires (black and black/yellow) with a green connector and they seem to route to the headlight switch (or at least something in the left controls). Any ideas what that might be?

Secondly, the safety relay - from the original setup, I've got the two mounted relays which account for all the wires in the diagram, then there's a third, separate relay, which I deleted from the setup. It fed in four wires - light blue, black, and two red/whites. Is this the headlight cutoff you mentioned? And could this be the reason for no headlight?

Thirdly, a most concerningly, I seemed to have bypassed the key entirely. As soon as I hook up the battery I've got power, and I can actually kick and run the bike without a key in the ignition. I think this might be because of the brown wire I've got hooked up to the main red coming from the reg/rec. Thoughts?

I really appreciate your help on this one, Leo.
I'm pretty pleased with my progress so far, considering I hardly knew a thing before I started! Couldn't have done it without the help. So cheers!

Speak to you soon.

-A

#1 With the RLU unplugged you need to put a jumper in the plug from the yellow/blue to the blue/black wire. This sends the power from the safety relay to the dimmer switch, bypassing the RLU.
That extra wire plug hooked to a switch on the clutch lever. On the 81's, a one year thing, to use the electric start you had to have the clutch pulled in and the transmission in neutral before the starter would work. On my 81 the wire plug in the headlight bucket has a jumper wire in it. So I have to have it in neutral before it starts.
#2 the extra relay you have is not a headlight cut relay. The XS650 used the safety relay to control the headlight. There was no headlight cutoff relay. I went back and reread this thread, I never mentioned a headlight cutoff relay.
That relay is a starting circuit cut relay and worked with the clutch switch and neutral light to stop the starter from working unless the bike was in neutral and the clutch was pulled in.
The two red/white wires, one carried power from the safety relay to the start circuit cut relay, the other carried power to the starter relay. The sky blue wire carried power from the neutral light, the yellow/black sent the power from the sky blue wire to the clutch lever switch were when the lever was pulled it sent this power to ground on the black wire. This tripped the starter cut relay so power could flow from one red/white wire to the other red/white wire.
I think most of the diagrams list the same one for both the 80 and 81. This is wrong the 81 had this starter cut relay that worked with the clutch and neutral light. In 82 they used the starter cut relay, along with a sidestand relay and switch.
#3 I looked a bit closer at your diagram. Guess I didn't look close enough the first time. The red from the reg/rec should go straight to the battery, then hook a red wire from the battery through a 20 amp fuse to the main switch. The brown wire to the red wire from the reg/rec should not be there. This is why you are bypassing the switch. Also the way you have it wired power from the battery goes to the main switch and bypasses the 20 amp fuse, it does nothing that way.
Leo

Leo, you're a legend!

I've updated the diagram based on your comments. Could you have a look and tell me if it will do the trick? I'm a pretty visual person.



If you're ever in Sydney, Australia, the beers are on me.

Cheers!

Ok, I looked closer this time. Now your power source is fused before it gets to your system. The battery and the PMA are the power source. when the bike isn't running the battery supplies the power, once it's running the battery is still supplying the power but the PMA is adding enough power to run the bike and charge the battery.
I bet your key works now.
Now lets do a bit of a walk through. Power from the battery and PMA is routed through the main fuse to the main switch. Very good, from the switch power flows on the blue/yellow to blue to power the tail lights and licence plate light.
Power also flows out from the switch on the brown wire to power the neutral light and the 3 ten amp fuses, From the fuse on the brown to power the brake light switches and horn.
At the fuses power flows out on a red/white wire that goes to power the ignition and to the safety relay, or SR. From the SR the red/white goes to the starter relay, blue/white to the start button. So far so good.
From the fuses a red/yellow wire to the SR, this is power to light the headlight. When the SR trips it sends this power out on the blue/black wire to the gauge lights and the RLU. Under normal conditions the RLU send power out on the blue/yellow wire to the dimmer switch, from the dimmer to high opr low beam. If the low beam blows the RLU sends power out on the yellow wire to light the high beam even if the dimmer switch is in low beam. It also send power to the headlight failure light.
This part I would delete, The RLU just chuck it. Use a jumper from the blue/yellow to the blue/black. This sends power straight from the SR to the dimmer switch.
The RLU is ok if it works, but often they short inside and either you get no headlight or just high beam. As much as you have simplified the rest of the wiring, why keep the RLU?
I juist noticed you have left out the turn signal flasher. But you mentioned that earlier.o real problem there, just add a brown wire from the brown wire already in your diagram, some where close to where you are mounting the flasher unit. Hook it to the positive side of the flasher, a brown/white to the negitive side then hook the brown/white to the brown/white of the turn signal switch.
As far as the rest of the wiring it looks good. Power to the horn on brown, pink to button. power to neutral light on brown, Sky blue to switch.
One thing on the turns, Are you using the stock lights? If so the single bulb indicater will work fine. If you use LED turns then it won't work. The single bulb indicater light will let all four turns light at the same time. You will need to use a pair of diodes. Hook one diode to the dark green wire from the turn signal, one diode to the Chocolate wire from the other turn signal. The othe ends of the diodes hook together and hook to one lead of the indicater bulb, the other bulb lead to ground. The diodes will prevent power from crossing ove to the opposite side, yet let the indicater flash for both sides.
If I'm ever in the land down under I'll be sure to look you up. I would love to take a year off and visit Austrailia and New Zeland. Maybe if I win the lottery I'll be down.
Leo