79 850G - No spark

[Goose]

Well, I'm sitting at work stewing over this. Probably a waste of time since I can't look at the bike to answer my own questions. I guess I just like to torture myself... ](*,)

Any way, this bike ran three days ago. Before cash changed hands. Of course. Now, the starter turns fine, I've charged the battery (off the bike), checked all connections, pulled plugs (normal, but wet), layed one and four on against the head - no spark.

Started the procedure to set points. Clymer says that, with the ignition on, manually opening the points should result in a spark. Not on 1 & 4. 2 & 3 only gets a weak spark between my screw driver and the crankend as I lift the arm of the point.

Questions: Should there be +12 vdc on the black and white wires of the condensors all the time with the ignition switched on? This would be a good place to start with the multimeter.

Also, is there a continuity check for the coils? Can't see them both going bad at the same time, but who knows...

Last question, since I don't have a schematic in front of me, is there a direct relationship between power (or ground) to the ignition circuit AND the regulator/rectifier circuit?

I always thought that the RR just controlled voltage coming out of the stator and charging the battery...

Thanks. I'll try and focus on my work now... :sad:

[mark]

Stuff to try in no particular order.

1. Check your ground at the battery box, the one at the front. Make sure the connection is completely cleaned. Check and clean all your electrical connections.

2. Check voltage from the battery to the orange wires going to both your coils. Shouldn't have more than about a 1 volt drop at the most.

3. Test your spark plug caps. You have 5 ohm caps its easy to check.

4. Make sure your plug cap connection to the wires are good. Unscrew them, and cut maybe 1/4" off the end of the wire with a good wire cutter and the screw the cap back in.

5. Try new plugs with your test. If your plugs have been wet fouled from a flooded engine etc, sometimes they won't fire after that. Makes no sense, but its true......have new spark plugs on hand.

6. Clean your starter button, on/off button.

7. Make sure your battery is in good condition.

8. Make sure your points are not pitted and adjusted correctly. I'll get you a good set of instructions for that after a bit.

9. Don't be afraid to get a new Dyna S ignition . I messed with my points ignition for a year, struggled with weak spark the whole time and finally just went that route. Best move I ever made.

[mark]

http://www.thegsresources.com/_forum/printthread.php?t=88522

Heres a great set of instruction for setting your points. Go down about 4 posts.

Since I have a Dyna S, I can't remember the specs for stock coils. Maybe someone else will chime in with those.

[Goose]

Thanks!

Appreciate the info, Mark.

What's a Dyna S Ignition do for me? Eliminates points and condensors?

[mark]

Appreciate the info, Mark.

What's a Dyna S Ignition do for me? Eliminates points and condensors?

Yes and better spark, reliability. Automotive type plug wires that can be replaced with ease. 3 ohm instead of 5 ohm coils. In my case the coils tested O.K., but the spark plug wires were really worn out and cracked, the wiring from the points condensers up through the back of the engine was bad and frayed.

Nothing against points ignition and done right they're fine, I just tried everything I could think of and never got the good spark I wanted. Subtracting the cost of points, condensors and maybe new coils from the price of a new ignition, it didn't seem like that much extra money for something better.

Check it out here.

http://www.z1enterprises.com/

[SqDancerLynn1]

I would check spark plugs for fouling. Check for 12V at coils with the points blocked open. The 850 will run on two cyl -not very well, so having both coils fail at the same time is remote. Make sure the petcock is working.
If your 850 has the original coils- REPLACE THEM. Use the new style dyna 3 ohm coils & use a balast resistor- from a mid 70's Mopar to work with your points system. My 79GS 850 has 41K miles, yes it still has the point system. So it is not mandatory to go to a Dyna ign.

[Goose]

Check for 12V at coils with the points blocked open.

Hmmm. That's a tasty bit of troubleshooting advice... It's been so long since I worked on a points type ign that I would have forgot about breaking the circuit to get an accurate voltage reading... Thanks, Lynn!

Check it out here.
http://www.z1enterprises.com/

Thanks for the link, Mark!

Before I go further, I've got this itching suspicion that I need to check my main ground...

[Goose]

It Is Alive!!!

And guess what? It was the freakin' main ground at the back of the engine!

What did it was, when I was cleaning corrosion off the battery with baking powder and water, a lot of it dripped down onto the ground and opened the connection. It was probably about half way there anyway, since the drain hose from the battery wasn't hooked up and that port on the battery was directly above the ground connection...

It was too late to ride it last night. I'll be hopping on for a ride directly after work today!