Wiring Questions and Problems

so long story short I bought an xj750 from a guy who my friends and I call mad max. I had him make me a cafe racer from a barn find, I’ve done a ton of research and it runs well, buuuuuuut...

His wiring job is “real simple” is how he put it. There’s a headlight that turns on when I flip the dummy switch (no keys in this girl), but I changed the headlight out and it doesn’t work!

I’m a newbie entirely and was wondering if anyone has any advice on how to solve my headlight issue, as well as how to install my tail lights. I have a left and right light for turn signals that aren’t wired in (each has two wires) and my brake light (three wires). I also have a new switch with several wires. I also have a horn I need to install.

I know I’m asking a lot but YouTube is failing me right now.

Help me XJBikes, you’re my only hope!

I’ve included the wiring diagram I’ve sketched (poorly) up.

 

here is the minimum wiring

 

2 indicator set up other photo is 1 indicator bulb set up

 

Note that the minimum wiring diagram is not legal in many areas. Depends on local matriculation laws. Most places require a horn.

Do you still have the control cluster with the horn switch? The factory configuration has the horn(s) get 12V from a brown wire (Signals power from a 10A fuse), and the other side is a pink wire that runs to the horn switch. The switch grounds the pink wire when pressed. The diagram shows it grounding to a black wire, but it may actually be grounding to the handlebars.

 

tbh i have no idea. in fact im so new to electronics im having trouble even reading the diagrams lol. i dont have a control cluster just a bunch of loose wiring really. i dont suppose anyone on the site makes wiring harnesses that i can just purchase? this part of my build is just infuriating and im at the point of just plug and play.

 

The harness isn't your problem at that point. The control cluster I'm talking about is where the horn, turn signal, and high beam switches are. If your bike didn't come with that, you should get one used off of eBay or from a MC scrap yard.

 

the green min wiring has the horn

so do you have the controls? those things with the switches on the handel bars next to the grips?
the 82, XJ 750 maxim controls are unique to the maxim not sure why

this link shows the few bikes for the left control that will work
https://www.partzilla.com/product/y...?ref=cfc5f31b6fac8722097cb87f77abe97186855339

right control is needed from an 82 by partzilla

 

there is always the M unit a little pricey but makes wiring easy.



what do you have for handle bars?

 

ok . what are your goals with the wiring?

bike wiring is simple to do .

 

alright i stepped away for a breather. sinking several days into the bikes mechanical stuff drained me.

ill take a picture of the handlebars in the morning but the controls are aftermarket.

what im trying to do, well, a couple things.

1) wire in the headlight, tail light, and brake light not directly to my battery and so i can use turn signals lol

2) understand what shortcuts the guy who made it did and possibly correct them (because there are odd ones. the tci has a couple wires snipped, but ive been riding the bike)

3) and as an added bonus, install some dummy switches along with the one i have. would love to flip a couple switches to turn on the bike like some airplanes do

 

last minute question as well. making an electronics tray under the seat but there snt a lot of space for the battery. the spot it was originally located was on a little shelf with a rubber strap. i kind of just want to keep it exposed rn but am wondering how i can keep it safe from the rain

 

i should clarify this is a stripped down cafe racer. zero fairings. i do some hobby metal working but my tig is down. i have my spot welder and grinders though!

 

start with a fuse box 4 to 6 positions. you will also need an ignition switch many on ebay if you go oem style. or just a key switch that will handle 20 to 30 amps.

battery positive feeds main fuse then main fuse feeds ignition switch the ignition switch sends power to the other fuses. that is the yamaha way of doing it.

from that base you can start to add circuits and flip switches

autoparts store for this part ask about amps. you can hide it away
Dorman 85936 Conduct Tite Universal Key Starter Switch
https://www.amazon.com/Dorman-85936...ion+switch&qid=1589022691&s=automotive&sr=1-2

 

wait so i have just a toggle switch under the bike that acts as the ignition switch (i like going keyless), is that kosher? total newbie here. and what do you mean fuse box 4 to 6 positions? do you mean something like this?

https://www.revzilla.com/motorcycle/rivco-6-circuit-fuse-block

and what would i get if i wanted to add circuits and flip switches?

im making a milk run to autozone as soon as they open

 

you could use that style box but you would also need an inline fuse for the main fuse from battery to Key or initial power switch

this is what you want to use minimum of for fuses but always nice to have more
https://www.ebay.com/itm/Auto-6-Way...100900?hash=item1eead8e164:g:SpYAAOSw3axeooAQ

 

what yamaha does with its fuse holder is power from battery goes to main fuse then to ignition switch ( or on off switch as you want to do).
then the power feeds back to fuse holder and connects to input of remaining fuses .

if you use the buss style block you linked to you would need a seperate main fuse holder good for 20 to 30 amps. to feed to on off switch then feed back to main line of the buss style fuse. this is equal to jumpering to remaining fuses as yamaha does.

your on/off switch needs to be rated for 20 to 30 amps so it will not burn out.

 

yamaha way



the buss style you linked to would distribute power after on/off switch but require seperate main fuse

 

so from that top 10 amp i should have a second wire going from the first to the second and then another from the second going to the third? also should i have a 30 amp fuse?

thank you so much for your help thus far!

 

yes that is the easy way . yamaha cliped jumpers ion in main harness instead of jumping at box.

second drawing shows how a buss style setup would be done . cleaner in the end as you have no jumpers and connectors to fail , just the feed wire

30 amp fuse is for atari setup so a 20 amp fuse would be good. the fuse is for protecting wiring by blowing before wires melt

 

sorry for the ruff drawings I will make better ones to post as many min wire people will want to see options

most important is 20 to 30 amp on/off switch for main power.
this link will help you
How to Use a Multimeter and Read Schematics and Wiring Diagrams.
and propper guage wire for amps read this link for choosing proper size wire and how to ID wire. you will want to color code or label all wires as well as keep a list of what you use and have hooked to.
http://www.xj4ever.com/catalog/d-4-wiring.html

the wire OD is 2.03mm - 2.19mm (.0799 to .0862"), then it's 20-gauge (20g) AWG or 0.40mm squared (metric size).
NOTE: 20g wire is rated for a maximum load of 11 amps of current at 12VDC.

If the wire OD is 2.26mm - 2.42mm (.0890 to .0953"), then it's 18-gauge (18g) AWG or 0.75mm squared (metric size).
NOTE: 18g wire is rated for a maximum load of 16 amps of current at 12VDC.

If the wire OD is 2.48mm - 2.64mm (.0976 to .1039"), then it's 16-gauge (16g) AWG or 1.25mm squared (metric size).
NOTE: 16g wire is rated for a maximum load of 22 amps of current at 12VDC.

If the wire OD is 2.89mm - 3.05mm (.1138 to .1201"), then it's 14-gauge (14g) AWG or 2.00mm squared (metric size).
NOTE: 14g wire is rated for a maximum load of 32 amps of current at 12VDC.
NOTE: 14g wire is the largest size wire normally found in the wiring harnesses on these bikes. Battery cables and the solenoid-to-starter motor cable are larger, of course, but of all the main harness and accessory wiring, 14-gauge is the largest that you'll find.

If the wire OD is 3.49mm - 3.65mm (.1374 to .1437"), then it's 12-gauge (12g) AWG or 3.00mm squared (metric size).
NOTE: 12g wire is rated for a maximum load of 41 amps of current at 12VDC.

If the wire OD is 4.32mm - 4.48mm (.1701 to .1764"), then it's 10-gauge (10g) AWG or 5.00mm squared (metric size).
NOTE: 10g wire is rated for a maximum load of 55 amps of current at 12VDC.

 

so i wired everything and now i have no spark. my multimeter says the orange and red\white wires coming from my ignition have power. when i press the start button it reads 10.5 volts on the wires. any idea on whats going on?

 

okay im at my wits end. everything was working before i rewired it. the ignition coils were getting power but no spark. it should have worked. best i can guess is not enough power to the ignition coil? maybe i needed to use a different gauge wire here and there? i have no idea on how to guesswork this one. any advice?

checklist-
everything worked before i touched the wiring.
followed minimum wiring guide well i think
ohm tested ignition coil and a okay
cranking power to ignition coil is 10.5v
brown wire from rectifier was 18g wire leading to a 3 way split of inline fuses at 12g i think. the on/off switch i have instead of a key turned on the accessories like the headlight through the fuse so i assumr theres power coming through the regulator?

infact what does the brown wire on the regulator do? what does the red\white wire off the slinoid do? so many questions

 

the red white wire gives power to the solinoid the blue/white wire runs to the starter button when pressed it is ground.

there is a brown wire at regulator that goes to brushes, a second brown wire goes to hot after the key this is to make the alternator work.

 

red/white wire see if you have this from ignition fuse wire runs to input side of kill/run switch then from output side a wire rums to solinoid and a second wire goes to connection on tci with 2 aditional wires running to ignition coils

 

Is the 10.5 volts when the starter is cracking? If it is before the starter is cranking your voltage is dropping to load of fire in the TCI. You either need to charge your battery, or check the connections you've made when crimping wire together.

 

yeah the 10.5 is while the starter is cranking. i just rewired it today, this time i used a 12g wire for the on\off, 10amp fuse, going all the way to the killswitch. still nothing from ignition coils. i did a dc voltage test on the black and red\white wires on the tci and turned on the power and its getting 11.5v. cant think of much else to do.

 

idk, ive been poking at it all day. i can get 10-10.5v cranking going in and out of the ignition coils. but no spark. could i have ruined the tci? thats the only thing i can think of.

 

Took a look at the tci. Noticed what looks like a burned section. Think it could be the problem? It’s on the ignition coil side. If it is the problem, any way to fix it other than buying a new tci?

 

so i said f*** it, hit the tci with my soldering iron, got spark. im going to bundle this beast, order a new tci, and see how well she runs. ive got a suicide run from la to the mojave (100 miles) and fingers crossed i make it. ill post when ive buttoned her up

 

Update, bike buttoned up. Runs really poorly rn. Wild guess is that it’s the tci. I’m ordering a new one and crying.

 

bought a fresh tci off a friend. works fine. now its onto the next problem. think i need to do a round of carb cleaning