G1 Suddenly Stopped Firing

[Palomino]

I have a 1979 Yamaha G1. The other day I was driving along and it just stopped running and now it won't start. I was going up hill, but not sure this matters or not.

I checked the sticky (but have not tested voltages yet). Here is what I have done:

1. Replaced seals on both sides (actually did this when it began to lose power last year).
2. Replace the spark plug. It is getting gas because the new plug comes out wet, but no charring so I don't think it is getting spark.
2. Replaced the coil
3. Did the $20 CDI replacement.

I have a guy that can test voltages, etc. but he is busy doing engine work he makes his living doing, so I am looking for ideas that I can check myself.

1. He suggested the key switch, but it still appears to work in both directions. The buzzer does not always sound in reverse, but when I tap the buzzer, it does work.

2. The pedal switch. The cart turns over in both directions, just won't start. Is there a separate kill switch or is this just on/off?

Any insights are appreciated. I am trying to get a few more years out of this cart. It also has some sentimental value.

[Lochlin]

Since your starter is spinning in both directions rules out a lot of stuff. You know your key switch is good, pedal switch is good, solenoids are good, starter is good, and associated wiring is good.

I bet your CDI went bad. Like anything else, those are all made in China now and they get taken out pretty easily by a voltage spike. It could be that your voltage regulator is acting up and allowing spikes. I would replace both and see what you have.

[Palomino]

Thanks.

I was having issues with the spark plug wire coming loose and that might have been what took out the CDI. I did try the $20 DIY CDI solution. Pretty sure I got it right, but I am not a electrical engineer.

I also checked the fuses.

Is there a quick test for the CDI and/or voltage regulator?

[Lochlin]

Originally Posted by Palomino

Is there a quick test for the CDI and/or voltage regulator?

Unfortunately, not really. The test for a CDI pretty much is "if the replacement works then the old one was bad" Actually, I think there are a couple of exotic tests that involve measuring resistance patterns when the timing magnets are in certain positions but I have never understood them much let alone had any luck with them. Maybe someone else has more info on it.

VRs are a little different. Their output can be measured and adjusted to make sure they are charging the battery correctly. In theory, I don't think that the VR should even be able to impact a CDI but I know it happens as I have experienced it. I have a non-G1 that kept blowing CDIs, I tried everything and just couldn't get it to stop blowing them. I eventually replaced the VR because I had tried everything else I could thinhk of. Everything has been good since.

You may just want to swap out your CDI as that's cheaper then take it from there.

[Palomino]

What role does the ignition relay play in the starting sequence and do those go bad as well?

[Lochlin]

Originally Posted by Palomino

What role does the ignition relay play in the starting sequence and do those go bad as well?

Funny you said that. I had that very thing happen to me a couple of months ago regarding the relay giving me fits.

According to spicyunicorn, one of the forums' experts, those relays intended to delay allowing the starter to turn for a second or two after the gas pedal was pushed to assure that the cart wasn't shifted too quickly to and from F and R. On my cart, the thing would run awesome until that relay got hot (either from engine heat or current going through it). Once hot the relay would not close and the cart wouldn't start until the cart cooled.

Personally, I don't think that this is related to your issue as your starter is turning so the relay is closing as it should. If that relay was an issue then your starter wouldn't turn at all. It can't hurt to jump the relay, though. Just cut the white wires on either side of it and join them together. Leave everything else as is.

[Palomino]

Hey, I just wanted to reply back that I followed the electrical tests outlined in another thread here on the forum and figured it out.

That test said something was up with the Pulsar magneto so I checked the wiring first and sure enough, there was a broken wire.

I jumped that wire and it fired right up.