XJ750 SECA - Electronics/Dash/Wiring - Bike not starting

Hi guys,

So I stumbled upon these nice forums and have been looking around and learned quite a bit in the past few months. I have bought a 1982 XJ750 SECA and had to rebuild my front brakes because they were sticking. That's all done, brakes are primed and bled and seem to work like a charm. However, to access my master cylinder I had to take apart a few things, including the headlight (which houses all connectors) and the dash console, which I basically unplugged and removed.

Now I put everything back together. Most connectors are unique, so all these were put back properly, however I did have a few trial and errors with single-wire connections, some were lost behind, i tried figuring shit out, and I turned the key ON to test things out while two were interchanged and 2 were not connected together. (I'm colorblind and those dark-green vs dark-brown vs grey wires are aweful).

So anyways, might have maybe possibly shorted something, i don't know. After reconnecting everyhting properly, still have a few odd problems:

- My dashboard has all those LCD (old calculator-type) displays for BATT, OIL, STND, etc. They used to flash once or twice and then turn off (then logically only the ones that have some type of error would light up). Now however they all stay on whenever I turn the bike on and stay there forever.

- The bike's engine won't start. I bypassed the big starter switch next to the battery, and it kinda "tries" to start (battery is full, starter solenoid is ok) but will not actually run (so maybe problem with the spark plug/gas injectors/air mixer things - I know nothing about how that works)? I also checked conductivity with the small starter switch on the handlebar and it is alright. I have been studying wiring diagrams for a few days and really have no idea what the heck is going on.

Is there a possible root cause? Could I have done damage to the onboard dash chip/computer?
The bike was fine before that - only sticking front break.

I can try to give any other information, I just dont want to overload either and scare people off.
Any suggestions are appreciated. I do have a multimeter with me and have been trying to figure out stuff, but really i know only highschool level electronics. P=UI and resistances are in Ohms and this and that.

Thanks a lot!
Nick

 

I haven't had mine apart in a while, but I recall that two of the larger white connectors are interchangeable. One of them is for the systems monitor. Double check that.
The engine won't start without the systems monitor being hooked up correctly.

 

Hi,
There is a relay which allows the starter to energise which relies on a neutral or the clutch being pulled and the run switch being on.
Pretty sure the sidestand switch comes into play also so... I would check all of those connections and then go further into your circuit diagram.
Sucks to be colour blind with all the damn colours in the harness but unless you cross black (negative) into some positive in the harness you shouldn't short anything out.
Don't forget that the plugs are a HUGE issue when it comes down to electrical issues on these bikes. Damn old (30 years+) and damn corroded depending on the geographical location.
Get that multimeter out and trace each connection before and after the plugs if nothing simple works.
Basic troubleshooting.
Good luck!

PS: (I replaced quite a few plugs/connectors from the copper inside the wires being corroded away. Give the wire a bit of a pull and if the wire is gone it will feel stretchy.)