5 seconds of spark

[Crazcnuk]

I am tinkering on the 78E and have an interesting problem.

Whan I crank it over, I get no spark out of any of the 4 plugs, but whan I stop cranking, 1 and 4 (left coil) buzz with a spark for about 5 seconds?

I tested the TCI, coil primary resistance is 1.6kohm at 34C and the ballast resistor checks out.

The PO has the red/white wire from the solonoid cut and going directly to the fuseblock?

[randy]

Craz,

The red/white is the ballast resistor bypass. it's supposed to have 12v ONLY DURING CRANKING. The PO has set it up to continuously bypass which may have damaged the TCI. The latent firing is usually caused by corrosion buildup on the TCI board, it may have gotten water in it or it may have water in it now. With the cover off and the connectors toward you, check halfway up the board on the right for goop, rust, mold or such and clean it up. Also pull that red/white off the fuse block and connect it back where it belongs. Let us know the results.

[Crazcnuk]

You missed the part about my testing the TCI!

I swapped the TCI with my 80SG and it worked ok in the other bike. I will try moving the red/white wire, although I believe that it is one of the wires comeing from the handle bar switch.

On the solonoid there are the + battery connection, the cable to the starter mortor and two smaller wires, which according to the wiring diagram come from the handle bar switch. The blue/white is still hooked up but the red/white has been cut and is no longer connected to the solonoid, but goes directly to the junction/fuse block.

There is also a red/yellow wire attached with the starter cable.

The handle bar switch is not there, so the PO had the kill switch bypassed and the red/white is live all the time.

Here is the neato 'fuseblock' system... The bright orange wire on the top, far left is the one connected to the red/white wire now.

[MindWebs]

wow....

wow, and i thought i was an idiot.

i don't bypass fuses.

i feel better about myself..

Thank you for sharing!

[Crazcnuk]

He didn't bypass the fuses, you can see all 4 fuse holders in the picture. He used a junction block, then crossed the circuits in and out the same side with the fuses used as jumpers!

Just glad i still have one of the upgraded fuse blocks on hand.

[Crazcnuk]

Ok, got the spark figured out. He cut the red/white wire, at the handlebar switch because it's the kill switch, and won't run if the wires are together.

I have good spark on all 4 now. Just cleaned the carbs, and will put them on tomorrow, and it should be ready to fire up.

[randy]

Ok, got the spark figured out. He cut the red/white wire, at the handlebar switch because it's the kill switch, and won't run if the wires are together.

My man, that is backwards.

[Crazcnuk]

What I meant was there is the red/white coming from the old switch, and the one coming from the harness. They look broken, not cut, so I assumed they should be 'fixed'. When I hooked the two wire ends together, the spark plugs don't spark.

I unhooked, or 'broke' the wire and now I have lots of spark.

The handlebar switch has no wires actually hooked to it, anymore, and there is no starter button. I will be picking up a whole assy as soon as I can.

The PO also found all the missing carb/air cleaner clamps which makes things easier. Should have it running tomorrow, depending on how the gas tank is...

[randy]

I unhooked, or 'broke' the wire and now I have lots of spark.

That's still backwards, it shouldn't have spark with the leads disconnected. Methinks you will find other wiring problems as you get deeper into it, like another splice hidden somewhere.

[Crazcnuk]

I know, but most of it seems to be around his wiring of the fuses. Once I put the new fuseblock and handle bar switch on, it should eliminate about 90% of these issues.

It was the 'backwards' that caught me, I couldn't figure out why I wasn't getting proper spark, so finally i just unplugged that wire, and voila, wierd as it seems.

[Crazcnuk]

Redid the wiring. Topcat's fuseblock, joined the red/white back together, both at the solonoid and at the handlebars, it all works the correct way now.

Had a loose connection behind the guages, had to track down.

The wiring is pretty much back to normal now, cleaned the connectors behind the fuseblock while I wa in there.