1978 kz 650 no spark

can a faulty rectifier cause no spark . the last time i road the bike everything went bright , the low beam burnt out , as did the 1157 taillight bulb .

Did you check fuses? High voltage popping bulbs may have popped a fuse. Check for voltage at the hot side of the coil with the ignition on.

If the regulator fails is can permit excess voltage to pass through the electrical system, and this could blow light bulbs and fuses. As stated, check the fuses. Be sure to test them or simply replace them because they can look ok even if they are damaged. This is because the filament inside the fuse can sometimes separate where it was attached to the metal cap. When this happens the fuse looks ok even though it will not conduct current. After you get the bike up and running test the regulator to ensure it prevents voltage from exceeding 15v. Ed

thanks ed , the fuses have been swapped and i do have a neutral light on . used to be green meant go . I have had this bike for 25 yrs now and has never failed. sat in a barn for six ( cyls were oiled ) , started 5 kicks after that one. this last time it was parked for 4 yrs , i think its jealous that i have been spending more tim on the harley saddle ,as well as another kz 650 cafe like bike.
i have a parts bike that i will start swappin some parts on .
"keep the greasy down"
wyatt

Did you check for battery voltage at the hot side of the coils?

i will , thanks vtec