weak, intermittent spark

[thewiz]

Ok ... Only had a couple of hours to work on it today, but my G has a very weak and only occasional spark. Engine cranks but does not start. Found a 'no start' check list on this site and started through it. Fuse block and main fuse good. Cuz it was easy to do, swapped out TCI, and coils from my running F, unplugged the tip over switch so far .... no help, still weak spark. Think I need to clean TCI connectors and run stop switch and associated connectors, check ballast resistor, check plug caps and wire resistance next .... but what the heck could keep this beaaahhhhccchhhh from producin' a healthy blue spark?

[randy]

thewiz;

1. Is your plug gap correct and are the plugs clean?

2. Cut 1/4" off of each plug wire and re-install the caps. Sometimes there is corrosion there.

3. Check the pickup coil gap, should be .7mm. You'll have to remove the timing plate to get a feeler guage in there and replace the center bolt with a few washers to keep the rotor on. Then use the rear wheel with the motor in gear to rotate the crank into position for each pickup

[pggg]

OK the sparks coming from the coils, hopefully they're getting the full 6 or 12 volts with no bad earth, and putting out 20 or 30,000 volts, btw I've run an XS11 - stock coils no ballast resistor, people will tell ya the coils will burn out, but mine ran fine for years, eventually ditched the plug cap resistors too, still don't understand what they're supposed to do but swear the bike ran better without them, people will again tell ya the black box will burn out if you try that but no worries there either.

[planedick]

Coils...

Try changing the coils with a known good pair. Sometimes the wires go bad.

[thewiz]

Uhhh .... Dick...

.... swapped out TCI, and coils from my running F ...

Uhh ... Dick, did this already , thank you. Got the stuff off the one I bought from Ernie which WAS running when I shut it off after the last time I rode it

Ok, Randy .... I'll be all over most of that, soon as I get off this confuser and onto the slab outside where the action is , thank you very much.

Pggg .... Thx, .... put a test light on the coil primaries and watched light go dim when it switched back to 6V after a few revs. Will get out the multimeter and check actual voltages and resistances next, I guess. Interesting about the no ballast resistor, too .... Resistor caps were probably used for radio noise suppression.

[Dragonrider]

Hate to suggest the basic...but did you check the voltage at the battery? Should be 12.6 or so fully charged. A lost/weak cell can get you voltage too low to get good spark, but still have plenty of current to turn the engine over.

When cranking it should not drop below 12.

Also, check the ground cable...especially where it attaches to the engine...

[skids]

Yes, check the battery. However, I think 12 volts as a load test on an xs11 battery is a bit high. (maybe 10v?)

Originally posted by Dragonrider


When cranking it should not drop below 12.

[thewiz]

Yepper, I had charged and checked the batt voltage then load tested at the very beginning. Read full charge on the machine and held a load well BUT I didn't crank it with the load tester hooked up. I have suspected the battery all along. Think I'm gonna' watch the Volt meter while cranking to note the voltages and then maybe even swap the batt out for the new one in my SF ... hopefully I'll have it sussed out and runnin' by tonight. Thanks everyone ...