Total ? failure

[Big T]

There I was, on my way to the Western States Rally, coming down Mt Hood, passing a semi, when my bike just stopped running.

I managed to finish the pass and get pulled over

I tried the starter, it turned over, but no fire

Then, the starter stopped working

The 5 of us tore into the bike and found

12V+ at battery
12V+ at both sides of the fuses
12V+ at the solenoid
12V+ at the coils
Dash lights on
Headlight out

Pulled a plug, no spark - somehow, the starter was working again. We managed to blow a fuse (lights) along the way

The battery finally ran down, we gave up, they split, I called AAA and got the bike home

After partially charging the battery, I have dash lights, the starter turns over
I swapped out the ignition switch for a spare. I have checked the coils as yet

So, my current plan is

1. Take battery in to be tested once it's charged. How much shoulld it drop when I hit the starter button? 1-2 V?
2. Check the kill switch (it's 100 degrees in my garage, I'm cooling off)

Now, you ask, Have I made any electrical changes recently? Yep, did the coil relay mod a week ago. The 12V at the coils shows it is working.

This is my 78 GS 1000 with a Dyna S. How do I check the Dyna S?
2 year old gel battery
No spark, no headlight

[BassCliff]

Hi,

12v at the coils but no spark? Sounds like the igniter, or whatever the Dyna S uses for an igniter.

Anyway, here's a link to their Dyna S Ignition System Testing PDF file:

http://www.dynaonline.com/skins/downloads/instruct/DynaSTSG.pdf

If the above doesn't work, here's a link to the download page. It's the first file under the "Dyna S" section.

http://www.dynatekuk.com/downloads.html

Sorry I couldn't be of more help.


Thank you for your indulgence,

BassCliff

[duaneage]

FWIW I would undo the coil relay mod, and do a wiggle test as well. Power up with a battery charger capable of delivering 10 amps and start wiggling wires until you find a bad connection or a fuse pops. Dio this with the engine off.

[Big T]

The mod's coming off later

I followed the Dyna S tests and got 12V at the trigger wires no matter where I set the magnet - so the Dyna's dead?

I pulled out my spare and mounted it. Temp wired it and still nothing. Checked the power wire and there is no power. So I wire it to a 12V source and POW - all the accumulated gas in one muffler went off,lots of spark

So I hooked everything up and - no spark

Pulled the tank again and checked for 12V - yep, 12V except at the Dyna power wire - rewired that and the bike started up. Put the tank back on - it started, ran for a minute, died and no starter !!!!!!!

I had to come in and shower - it's too effing dark and hot right now

[almarconi]

Is it possible that a wire is pinched under the tank causing a short?

Check your ground connections and check for pinched connectors.

[simon kuether]

[QUOTE=almarconi;1243005]Is it possible that a wire is pinched under the tank causing a short?

Had that happen to me .

Cheers , Simon .

[Nessism]

Sounds like a bad power lead, feeding both the ignition and the head lamp. How about tracing it backwards to see what could be going wrong? I've heard of old fuses being fussy too so you might want to replace them all with fresh in case you have never done so before.

[Big T]

Thanks for all your replies

It was the relay - I tore it off, fixed the wires back to stock, some solder, heat shrink and tape later - 1,800 miles down to Reno and back

Logically, I can't account for what happened. There's no reason the relay mod should affect the spark, or power feeds, or any of the other things that went bad.

All I know is that it worked.

[Matchless]

Unless the relay mod was not done correctly and there were poor connections somewhere or the relay itself failed, but you measured 12 volts on the coils?? Same wire feeds 12v to the igniter...

[duaneage]

You are not the first person to have a problem like this, someone else got stranded by a bad relay.

[UncleMike]

You are not the first person to have a problem like this, someone else got stranded by a bad relay.

Damn. I was just about to do this mod, too.

Now I'm having second thoughts ...

[almarconi]

Damn. I was just about to do this mod, too.

Now I'm having second thoughts ...

You can still do the mod, its a worthwhile mod. Just carry a spare relay if it makes you feel better.

[lucabond]

I did the coil relay mod and had my RR go and put out 50 volts which blew my relay. If I had a spare relay since i used a plug to install it i would just had to unplug the bad 1 and plug in a good 1 to replace it. That would have taken care of the bad relay and in my case had I just cut the red output wire from the RR I could have made it back home on the battery.
The moral of the story, how often would an RR go and take out the relay but adding a spare relay to your tool kit is cheap insurance.

[Big T]

Unless the relay mod was not done correctly and there were poor connections somewhere or the relay itself failed, but you measured 12 volts on the coils?? Same wire feeds 12v to the igniter...

No igniter, Dyna S has separate power lead

[Big T]

Damn. I was just about to do this mod, too.

Now I'm having second thoughts ...

I think it's a material issue

I've had a horn relay for over 20 years - I used a Hella headlamp relay for halogen lights (pretty new back in 82). It's about a 3/4" cube with a mounting bracket, perfect for bikes

The relay I got from Napa is much bigger and mounted by the socket. The relay would pop out under hard acceleration, and I think it shorted somewhere inside.

I'll search for something more suitable and try again come November, or when I get the Fridge up and running