1977 yamaha xs 650 no spark?

[slayer123]

i just rebuilt the top end on my 650 and was ready to start the engine. i hooked up the battery to ground on the starter, and the positive wire to the brown wires on the two coils, and the left coils orange wire to the grey wire on the left points, the right coils orange wire to the orange wire on the right points, and then connected both black wires from the condenser to the left and right coil wires too. i have a link of the wiring diagram i used to start it minus the stator and the rectifier. i didnt hook up the stator or rectifier so the battery wasnt being charged. i had spark, it was blue. so i finnaly kicked the thing over and it was running good and i was trying to tune the carbs on it then the on/ off switch i wired to it bumped the frame and started sparking and the starter engaged. nothing got damaged but now i have no spark at all. i did notice the battery was at about 9 volts today too. and i did notice when i pulled the throttle the thing would rev up but than after a while when i pulled the throttle the thing would bog down and back fire. did i fry something? when i use the test light on the coils it lights up along with the condensor too. i do have an extra set of points and am going to hook up the regulator and stator too. any advice? i bet it is something simple! Thanks!

 

[gggGary]

Coils HATE being left on, did it sit for a while with juice flowing while not running? That'll burn points too.

 

[slayer123]

not more than maybe 20-30 minutes unless i left it on longer and didnt realize it. what does it do to the points? turn them into complete duds? i had the thing running for about ten minutes at a time too.do you think my coils are messed up too?

 

[gggGary]

A minute or two can fry them. Here's the excerpts from the manual, the components are easy to test. You don't need the fancy spark gap tester.



Check high tension leads also. I have found bad condensers on XS650s several times, Condensers tend to die from old age, there's a reason the old car tuneup kits always included new condensers..... Carefully check high tension leads and plug caps also.

 

[XSLeo]

Also most ignitions don't like dead batteries. At 9 volts your battery is dead. Charge it.
Use a good motorcycle type charger. A car charger has to much current. It can over heat your battery and warp the plates. One of those cheap trickle chargers can charge at too high a voltage and boil the water out.
A good motorcycle charger has 1.5 to 2 amp charge rate as well as a computer chip the constantly monitors the battery voltage. It starts with the full rated charge, when it reaches about 13.5 volts the current drops to around .1 amps. This maintains the charge at the 13.5 volts. Any charger that goes over 13.8 volts boils the water.
It seems I often overdo talking about chargers, but I think more batteries have been ruined by using the wrong chargers than any other reason.
And for a $20 Schumacher Charger from Wal Mart will prevent it. Look in the battery section. It's the small one that has the motorcycle on the box.
Leo