84 1200A no spark

[Tory]

A friend called with trouble,
His 84 aspy lost spark just out of the blue.
He was riding last night with no trouble.Stopped twice for gas and such
The first time it started hard, the second time it did not start at all, no spark.
On a 1200 where should we began to look?
Is this a common gremlin with them?

 

[dan filipi]

I'd start by checking if power is reaching the coils.

There is a wire common to each coil, I think it's black which goes to the resistor first.
There should be 12 Volts before the resistor.
I can't say what it should be after the resistor, maybe someone else knows.

 

[backlander]

Tory you should have 12v on the blk/whi wires to the primary side of the coils. If you do, with a test light, check the blu/yel and the yel/blu to the coils by turning the engine over, the test light should pulse on and off on each wire. That means the pulse generators are working. If they don't, backtrack those wires to ECM. IF they are good, it means a ground is lost somewhere or the ECM is bad. There's a test procedure with pictures of where the connectors are located in the Electrical Troubleshooting manual in the gallery. Just remember not to hook up a volt/ohm meter to the ECM because it's transistorized and will harm it.

 

[Tory]

This thing has an ECM?
No wonder I like my 1100
O thought it was odd he lost both.Could.it be a fuse?

 

[backlander]

Yes, it is a 10 amp fuse #4 which odd as it may seem, is the last fuse in the box towards the seat. They aren't numbered in order for some reason.