intermittent and no spark. please help!!

[elm327]

1980 xs eleven special. when bike sits it will not spark. pull plug and check for spark i sometimes get the occasional spark while cranking. iresearched in other threads and have examimed and cleaned connections in wiring. i did by pass the handlebar off and on switch and here is what i get, i just have the 2 off on wires skinned and connected together. if i crank motor and then stop and touch the off on wires togeter i get spark for a few seconds without the motor cranking. im really baffled as sometimes the bike will fire and run like a champ. any input would be so helpful!!

[motoman]

Not having the earlier scoot, I'll throw out something that they had that can cause that issue.......ballast resister. Others will chime in who are more familiar with the earlier 2H7 electrical systems.

[rover]

spark

Sounds like pick-up coil wires. Under the front cover on the left side are the pick-up coils. Due to the partial rotation of the vacuum advance, the wires from the coil can break inside the wire insulation. Pull on them and see if the insulation takes an hour glass shape. If so, you can either solder splice the wires with heat shrink, make new ones with tester leads, or maybe parts and more still has the new pulsar coils. I had this problem with my 79 SF in 1980. Took me almost all summer to find the problem, then told a dealer about it, and we sent word to Yamaha, and they came out with a service bulletin update.