Won't start, I'm stumped...

[drsfmd]

This started a couple of weeks ago, as I was on my way home from getting new tires installed. Most of the first few paragraphs probably isn't relevant, but I'm putting it in in case someone picks up on something I missed.

As I was riding home, the bike sprung a leak in a radiator hose, and would spray out under higher RPMs, so I took it very easy coming home. I changed the hose that weekend, and all seemed well. I did NOT overheat the bike, and only needed a few ounces of antifreeze to top it off (though I changed it all when I changed the hose).

I took a test ride to make sure the new hose was not leaking, and the bike stalled a couple of times. It started right back up each time, but as soon as I would come to a stop in neutral, it would stall. Pulled it apart when I got home, and discovered that the air box had come off of the carbs. I reinstalled, and tightened it all down, and it started right up and ran fine, but I didn't have time for a test ride.

Last week I started it up, and it ran awful-- wouldn't idle and kept stalling. Eventually I got it to run a bit, but it wouldn't rev-- then suddenly it was running fine. I chalked it up to a bit of water in the gas or something similar.

Yesterday, I tried to start it up, and it would start, but would not rev at all. It would immediately stall if I didn't keep it at full or near full throttle. It would not run above 1k rpm, even at full throttle.

Today, I went to the garage with some time to work on it, and couldn't even get it started... it just turns and turn without firing (and a very occasional backfire).

- I swapped in a new voltage regulator (which didn't make a whole lot of sense, but I had one handy).
- I checked all fuses
- I pulled a plug and check for spark... yes, I have spark, but it's a yellow spark, not bright blue like I would expect.
- It's getting fuel
- a new AGM battery is fully charged and spinning the motor over plenty fast.
- stator checks out ok with an ohmmeter. Obviously I can't check output when I can't get it to run... but it should run without a stator at all if the battery is strong, right?
- Fuel pump is working.

At a loss for what to look at next, and I'd welcome any suggestions you guys might have.

[et_miller_87]

I would start looking into that weak spark first. Yellow spark is obviously a sign its weak. May have some excessive moisture from your leak could be causing a short. Investigate the plug wires and coils for corrosion or moisture is where I would begin

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[drsfmd]

I would start looking into that weak spark first. Yellow spark is obviously a sign its weak. May have some excessive moisture from your leak could be causing a short. Investigate the plug wires and coils for corrosion or moisture is where I would begin

My local auto parts place didn't have the plugs I needed, but I plan to order them in the morning-- it's cheap medicine... the plugs were a little sooty, and they only have a few hundred miles on them. I knew it was running a little rich-- it might be more than a little bit too rich, but I don't know why that would cause non-starting issues. The wires are good as near as I can tell. I see no evidence of corrosion, but beyond that I wouldn't know how to check the coils (and they wouldn't both fail at once, would they?)

[et_miller_87]

I wouldn't be surprised to hear they both failed if they got wet while your hose was leaking. I see a couple things though, you had a good running engine, stuff got wet, it runs like poo now. Weak spark, chances are it isn't the plugs. It's more likely to be electrical since you said there is sufficient fuel. Rule of thumb , when you fix something, and it starts doing something odd, go back through everything you did before. Its likely it may have been caused by a recent repair. We're all guilty of something like this happening. It could be as simple as a connector is not seated all the way. It's a very tight fit down in there and could be simple as that. But since it did spray water, id feel like it's worth a second look and a deeper inspection, if it were my bike anyhow.

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[drsfmd]

I really doubt the coils got wet, but I'll pull it apart anyway. The leak was on the other side, down low, and pointed towards the ground (ie: sprayed on the headers).

I should also point out, despite the fully charged battery, the horn is behaving as though I'm attempting to use it with a dead battery -- you can hear the horn *try* to make a noise, but it doesn't-- just a little noise from the diaphram in the horn.

In the next few days I'll really dig in and see if I can find any burnt wires or connectors too. A cursory glance didn't show any issues there, but most of the harness is wrapped in electrical tape (or whatever that black covering is)

[et_miller_87]

Well I guess I should of asked which hose! I assumed it was the top one. Could just be a scrappy connection in there somewhere. Happy hunting

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[drsfmd]

I found a post at another site that suggested that the analog igniter was a POS. I went out to the garage, and have confirmed that mine has the digital ignitor-- despite being an 89. So I guess it got swapped out at some point. Plugs are part of an Amazon order that went in this morning, and I'm hoping to get lucky and find a burnt wire or connector before that package arrives. Any thoughts on the horn not working? It's always worked up til now. I guess I'll have to find a schematic online, and see if anything related to the ignition includes the horn wiring-- that might help me narrow down where to look.

[drsfmd]

Another possibility I found... apparently the failure of the kickstand switch can cause this. I'm going to bypass it and see where it gets me.

[et_miller_87]

Howd that turn out?

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[drsfmd]

I didn't get to it today. It was in the 90s with high humidity, and I only had a little time after work before I had to go deal with an issue at one of my apartments. Maybe tomorrow...

[et_miller_87]

I didn't get to it today. It was in the 90s with high humidity, and I only had a little time after work before I had to go deal with an issue at one of my apartments. Maybe tomorrow...

Man that sucks. Down south somewhere? Weekends are the paradise for troubleshooting

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[drsfmd]

Man that sucks. Down south somewhere? Weekends are the paradise for troubleshooting

Believe it or not, New York. We get the "best" of both worlds... it's got the heat and humidity of the south in the summer, and the brutal cold and snow of Alaska in the winter. Those two weeks of spring and two weeks of fall are absolutely glorious though!

[et_miller_87]

That is rather suprising to hear. Well hope you get to it soon.

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[drsfmd]

It's running.

I changed the plugs, and discovered that one of the hard plastic boots for the spark plugs (cylinder 2 to be specific) had cracked, and was shorting out. I need to find a replacement boot for it, which may end up being another online order, as the local auto parts places only have angled boots.

The plugs were very fouled-- so I'm going to need to adjust the mixture to lean it out a bit. I've already got the gas tank out-- and I'd really prefer not to take the carbs out unless absolutely necessary. I haven't fooled with those fuel mix screws before, and the factory manual doesn't cover them at all. Any advice (or even better, a tutorial) from someone who has actually done this already?

[et_miller_87]

YouTube is your friend. There were a couple videos on there that are very helpful when it comes to adjustments.

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