79 1100 xs

I have a Yamaha 1100 XS 1979 Classic.

I need help? Sometimes theres a little spark out of the plugs and then sometimes theres not.

Items I replaced so far is the following:

Ignition Unit.

Complete wiring harness.

I also, tested the Coil wires for current.tested O.K.

I tested the 4 distributor wires for current and I don't get any current from them.

I was told from a shop that I won't get any current from the Distributor wires until

it reached a suretin RPM. Is this true? Or do I need a oeum Meter?

Can someone help me?

Thanks.