[cjb]

I am trying to fix an ignition problem with my 1977 Yamaha XS 650 motorcycle. There is no spark at the plugs.

[ashdad]

Try new wires then check the coils under the tank.
Also try http://www.650motorcycles.com/ for all sorts of info on your bike

[void]

Change your sys. To 1980 elec. Ign.
Its apain, but it ends there [if you do it right the first time.]

[xs650 chopper]

You may also want to check out www.xs650chopper.com Use a voltmeter and check each component. Work your way through the systems one component at a time.