Motorcycle Repair: GL650 Starting Problem, matchbox size, size boxes

Question
Starter turns engine over.  Rather than starting, the engine gives periodic
backfires.  Shop has checked all the likely suspects; petcock, CDI, timing and
believes problem is "electrical in the ignition system".  What would you check
next?  Thanks.

Answer
Are the compression readings ok?
Does it have spark?
Are the plugs black (rich) or tan (ok), white (lean)?
Does it have CDI?, the 650's usually don't.
They have transistorized ignition,
two little matchbox size boxes behind the battery.
If it is CDI, I suspect the stator is bad
or shorted out.
If it is not CDI, I suspect the pulse generator
in the engine side cover.
If it has spark and
if it is a fuel problem, the bike should fire
if you spray some wd40 in the intake.
Make sure you check all the simple things first,
like spark plugs, gas, battery etc.