xj650 ignition circuit problems

Hi all, wondering if the power of the internet will be able to shed any light on my problem

its something I have never come across, so Im a little stumped

I have an XJ650 engine thats been removed from a complete bike (bought as a spares wreck) with the intention of giving it a new life in a one of frame etc

I first wanted to fire it up and check that it was at least half decent before I went any further

crank the engine over and no spark, ok Im hardly surprised, the wiring loom is hideous

so I strip it back to the bare minimum and wire it with new wire

I have the CDI unit, into this is plugged the wires from the pickups, both pickup coils are reading as fine with a DVM.

the other plug has a live feed that also feeds the live of the coils, an earth, and the 2 trigger wires that go to the coils.

spin the motor over and no sparks?

ok lets go thru it again, I try from the furthest point, ie at the pickups, if I use an allen key or similar to fool the pickup into thinking that a piece of metal is passing the pickup then I get sparks at the plugs, ok so that seems to work fine.

if you rotate the allen key while its laid across the pickup, then I can get a constant flurry of big sparks at the plugs, so the coils and the cdi are working

crank the engine over and nothing, nadda zip

Im confused LOL.

I even went as far as turning the engine over on the crank with a cordless power driver to eliminate the starter motor as possibly doing something funny or drawing too much current

the rotor has been swapped out for a different one, still no difference

the wiring is as above so theres no starter lockout, no switches etc. and I have prooved that the system as a whole works, as I can get big sparks at the plugs laid on the head by using a metallic object on the pickups

HELP please

 

I know you said that one of the plugs feeds an earth, but are the coils earth wired to the frame from the loom? You know, that wire with the metal ring coming from the loom that bolts to the coils and frame.
Long shot maybe i know, but i'm thinking that you could have been the earth when you held the allen key and passed it over the pick ups.

 

Hi thanks for taking the time to reply, Im no stranger to engines, been building bikes for nearly 20 years, but never seen anything like this LOL

I have 2 engines sat on the bench, so decided that they are easy to work on and dont want to mess with any of the running bikes

so I have engine 1, put all the wiring on it as described above, and nothing, nadda zilch when its cranked over

I swap the pickups, rotor, coils and cdi to the other engine, and I get a flurry of sparks when that engines cranked over

tried swapping the starters just in case they are doing something silly and no change

Im totally baffled.

the good thing is that at least I know that one of the motors can be got up and running on the bench, but I just dont understand how moving all the electrics from one engine to another it doesnt work??

 

I was wiring up a newly re-built FJ engine and was getting nowhere until i wired in the neutral light and oil level light and then it fired up.
Could it be something similar?
It seemed like it was completing the circuit to make it fire.

 

Okay so these may be stupid questions, but do you have your coils reversed? Are you sparking 2/3 when you should be sparking 1/2?

What compression results are you getting?

Valve clearances?

What condition is your carb rack in?

 

I suspect FJ1100 is right in that you're doing something significant inadvertently. Have you done the tests with someone else watching, or asked someone else to do them while you watch. Sometimes hese tests just don't seem to be repeatable...

 

With the Power ON.

See if you have +12V at the Terminal FOR the Yellow/Black Wire at the BOX.
IF you find +12V Showing ::> Ground the Circuit.

If there is NOT +12V at that Terminal, ... you have to Supply +12V to the Safety Circuit Terminal ::> Black/White Tracer

 

thanks guys,

I dont have that extra wire on the box of mine, think thats only a USA version??

its still totally bonkers, I literally have a tiny standalone loom wired up that I can pick up and move

in the end I put the motors side by side on the bench

spin over one with the ignition setup on that, and I get sparks fromthe plugs laid on the head

plug in the pickups from the other motor, move the plugs over to that engine, and nothing, swap over the picks, nothing, swap over the rotor, nothing, even swapped over starter motors, and nothing

Im no stranger to bikes, been building stuff for nigh on 20 years or so, and the wiring up is my favourite part, its what Im best at.

but this has confused the living daylights out of me LOL

will just go with the good engine for now

 

Look at the Mill with NO Sparks.

At the 10 O'Clock Position on the Left Side Shift Cover is a Small Metal Cable Guide.
It prevents the Pigtail of the Ignition Pickups from slipping down the Case and being entangled in the Shift Lever or your Foot.

Insure that that wire has not been "Pinched" in any way that would Ground or Sever the Wire caught between the Case Cover and Lower-end.