spark & coils

[Shawnb]

hello if you have a light spark that intermitent what would cause that.

[Shawnb]

reply

weak coils insuffiecient spark , i got it ,still trying to repair a mess. Thanks for all the help on this site.

[mro]

Not unusual for there to be corrosion in the plug cap/plug wire connection.
Plug wires are long enough to cut ¼ inch or so off the end, clean cap and reinstall.
May not solve your problem but can not hurt it.
If you have not done so yet, not a bad idea to spend a few hours and clean all the electrical connectors and grounds on the bike (including those in the head light bucket and behind fuse block)
Doing so may help prevent some frustration trouble shooting electrical problems.
When I get a “new” XS I remove the seat, tank, side covers and open the head light bucket and clean the connections from one end to the other. Does not hurt to check the ignition switch and handle bar controls either.


mro

[Espiritus]

Wiring mess

My wiring is a total mess. It is wrapped from one end to the other in thick electrical tape. How does one clean wiring? Is this a winter project as I would like to replace all the wiring and redo it? Are the wiring harnesses on ebay worth the money or is it better to do it one lead at a time with all new wiring? I can run wire from one place to another in a house and rewire lights and switches so I am not totally ignorant of wiring, but how compatible is this?

Sorry to add to your thread, but saw where MRO had said to clean your wiring and thought that I would ask just HOW that is done.

Cam

[TopCatGr58]

Hey Cam,

MRO was talking about cleaning the WIRING CONTACTS, the plugs, not the actual wires. IT's the place where the contacts/plugs come together that corrosion can form and cause lots of problems, resistance, intermittent current flow etc.!

Shawn, several factors can affect and cause a weak spark. Aside from corrosion between the cap and wire, there is also a resistor INSIDE The cap, you can measure the resistances, should be between 5k and 8k, any more and you may need to either take the cap apart...unscrews at the spark plug end, resistor segment inside with spring, etc., clean, measure resistor after cleaning, if still too high, replace cap, otherwise put back together.

Didn't check to see what model/year you have, but unless it's an 81, then it has a ballast resistor which provides a reduced amount of voltage to the coils once the engine starts to prevent burning them up, it's bypassed during the starting cranking phase. Poor contacts on the TCI connectors, the solder joints on the TCI itself can cause intermittency. Also, spark plug coils can fail as well, so check the resistances for the primary and secondary sections, ~1.5 ohm Primary, ~15kohm without the plug caps for secondary.

And don't forget the pickup coils, again see tech tips, wires fail, crack, etc., replace as needed.
T.C.