1977 xs650 randomly dies

[slayer123]

so i have the thing idling fine. when i give i rev it up the thing sometimes randomly dies. and im not talking it sputters or slowly dies. it just dies. when it does this i will go to kick start it again and it wont fire up. its almost as if someone were to shut the thing off by the key or it has lost spark. but this couldn't be the case because i checked and it has spark. another thing i noticed was when i rev it up and than release the throttle it almost seems like one of the bs38 diaphragms is sticking open slightly because it sometimes will be above idle slightly. i do have a 135 main jet in it and a 27.5 pilot jet in it with some pod filters. i checked the plugs and they were black so i adjusted the idle air screw out a few turns and they seemed to be a bit better. dont know if this matters but its more info. any info helps thanks!

 

[retiredgentleman]

so i have the thing idling fine. when i give i rev it up the thing sometimes randomly dies. and im not talking it sputters or slowly dies. it just dies. when it does this i will go to kick start it again and it wont fire up. its almost as if someone were to shut the thing off by the key or it has lost spark. but this couldn't be the case because i checked and it has spark. another thing i noticed was when i rev it up and than release the throttle it almost seems like one of the bs38 diaphragms is sticking open slightly because it sometimes will be above idle slightly. i do have a 135 main jet in it and a 27.5 pilot jet in it with some pod filters. i checked the plugs and they were black so i adjusted the idle air screw out a few turns and they seemed to be a bit better. dont know if this matters but its more info. any info helps thanks!

Those are not the correct jet sizes for 1977 carbs. "Tech" section has a chart in the "Carbs" section.

 

[slayer123]

i just went to start the thing again and of course it died. i tested it for spark and what do you know i have nothing. the spark was white but than sometimes blue when i tested too. i know a blue spark is good and white spark is not so good. is it possible for coils to lose spark one moment and than have spark another? i do have a new condenser on it with new caps and wires. can my coils be toast because of a bad regulator and rectifier? mine are beat up and not charging my bike. ive been starting my bike on a trickle charger too because of this

 

[5twins]

You can't throw that large a main in that set of carbs without leaning the needles a step. That's why your plugs are black. And even with the needles leaned, a 135 is still probably a bit too much. A 130 or 132.5 would probably be better. If the bike isn't charging, it won't run right, simple as that. The ignition needs a near fully charged battery to function properly. As the battery charge goes down, the ignition will begin acting up and the bike will run worse and worse. When the battery gets too low, it won't run at all.

 

[slayer123]

but i had mine on a charger while it was running? is this still not so good?