Intermittent Starting issue

[BillyC]

Hi. I just had a problem with my 85 Shadow 700.

So I was riding it and then I parked at a friends house. When I went back to start it, it wouldn't start. The battery almost died, it was cranking and cranking, but it wouldn't even attempt to fire.

Then at the last minute there was a LOUD LOUD pop, I almost dropped the bike it was so loud, I thought it was a gunshot! Not kidding! Sounded EXACTLY like one! And then the engine finally started. It ran just fine, and I drove it home.

When I got home I shut it off, and tried to re start it. It did the same thing. Wouldn't even try to start. I kept trying until the battery finally died. So I connected the charger to it and let it charge a little. I tried again and it cranked for a little while, and then an even louder backfire! Right now my left ear drum may be busted, I can't hear out of it very clearly it was SO SO loud! Just like a cannon or bomb, no kidding! Then if finally started up and ran fine without a problem.

I shut it off and instantly tried to start it again. It just wouldn't start, and I tried and the battery died and I gave up for the night, as I'm tired and don't feel great.

So where should I start? I'm thinking MAYBE its getting flooded? Weird thing is it doesn't even hesitate for feel abnormal in any way when its running. Its just restarting. It did this once a while back, but I've never had issues since.

Do you think the engine is getting flooded? Or is it a spark issue? Loose connecter? Valve issue? Carb issue? I KNOW it has good compression, air isn't an issue, so its got to be Fuel or spark. Oh and it SOMETIMES fires up without issue now, not always though.

ANY ideas will be very appreciated.

I'm gonna go and try again tomorrow and probably pull the whole thing apart if it continues to do this.

I just want some starter ideas. Now I can't ride it anywhere, as I will fear it doing this once again when I restart it.

[ernie12b]

sounds like the hard to start warm problem. check the plugs, wires, battery, air filter if that is all ok the coils tend to get weaker when hot this is a sign they are starting to fail.

[BillyC]

Thanks for the reply ernie. I'll definitely check all these.

One thought I have though it don't these bikes have 2 ignition coils? These have 2 CDIs, 4 Spark Plugs+ wires, so I think 2 ignition coils.

Thats the only thing that makes me wonder. Because if I take one spark plug off each cylinder, it will still run fine! Its weird, but I think this design is for better reliability and spark or something.

But I'll definitely check this out.

The carbs have recently been cleaned, the batteries good, the air filter is good, and the wires seem okay.

The only real weird thing is that it has to be both cylinders. These bikes have 2 carburetors. The bike WILL start on one cylinder. Therefor if flooding is the issue, both cylinders must be flooding. I was thinking a leaking float valve or stuck open float, but the chances of both doing it at the same time is extremely low.

Any thoughts?

[BillyC]

Its still doing the same thing.

It was hard to start cold this time though. I had to connect it to the charger and crank it and crank it. It finially fired up and ran perfectly. This time no backfire [But I had my ear protection on this time incase!]

Once running it ran fine. Took it for a little ride and no issues the whole time, runs great. Took it back home, shut if off and tried to restart. Engine failed to start again.

I seem to smell a slight whiff of gas, but I believe there may be a small leak around where the fuel line connects to the petcock on the reserve tank. I DON'T think this is related though, its a slight leak and I will be replacing the hose today. But more importantly is the engine's issue.

I am THINKING its flooding, but I'm not sure.

Maybe its a spark issue. The plugs look fine to me. I am going to go and do a spark test on both sides, just see if theres a clean spark.

[93gc40]

Could just be a weak battery...... Or dirty run/stop switch or starter switch?

[ernie12b]

my 500 will not run unless all 4 spark plugs are working. not sure about the 700. is the choke adjusted properly? low battery or bad connections can cause this also. do you have a fuel pump?

[TheDogofWar]

+1 on the battery and coils. Backfire can be a sign of late ignition and most certainly is possible with a weak ignition.

[BillyC]

93gc40 could be. It did seem that the starter needs to spin a decent speed to get it to run. Thats why it seems to start better with the charger. It may be the switch as well.

ernie thats weird my 700 runs fine without all four plugs. It'll even run with 2 plugs, or on one cylinder or any of those combos as long as theres a plug!

I tested the spark today. It appears to be okay. But I only tested it for a little bit. It did the same thing today again! I start it, it runs great, shut it off and instantly it won't even try! I am starting to think its got to do with spark, but I'm not sure. I am going over the wiring anyways so I'm going to check out all connections.

And ernie yes I do have a Fuel Pump. When I first got the bike the original pump had failed, so I have replaced it. It works, and I know its always working as I have clear fuel lines and I can see the fuel going through.

And what do you mean about the choke being adjusted properly? Is it adjustable? I am pretty sure they work, and I know not to use them much or it will flood.

TheDogofWar hmm yea I am starting to lean towards spark.

It is pretty weird. I am going to go check a few little things tonight. Any other ideas? Thanks so much for the help so far everyone.

[BillyC]

I am now almost certain that it is the ignition/spark.

Today I was trying to restart it and when I pushed the Starter button all that happened was the headlight dimmed. The Starter motor wouldn't even try to turn and there was no sound. It kept doing this for a while, wouldn't even TRY to start. Then I kept hitting the back brake and moving the kickstand around wondering if there is some sort of a switch. Eventually after about 10 minutes it started to try to start. But it wouldn't, just kept backfiring and not even attempting to start, almost like its out of gas. But its got plenty of gas, the carbs have recently been cleaned very well, there are no air leaks, the fuel pump definitely works, sure beats me.

I am wondering what I should look for. See I ain't real good with electrical systems. I can work on mechanical parts but I don't have lots of experience on ignition and wiring.

As far as I know, it seems like it would be unlikely to be the CDI or Coils. WHAT are the chances both would fail at the exact same time? NOt very high IMO. Not that they haven't failed, just seems less likely.



So what you guys think? I really need help, I need a reliable highway bike right now. All I have is a couple of Scooters and a bunch of project bikes that are being restored to get me around. I can't even drive this thing to the gas station right now, I don't trust it and I can't count on it getting me to anywhere.

I know its probably simple, no big deal. I know its a Honda and its reliable as anything, just right now the electrical system is sucky. Also the taillight is out, the brake light works and I tried to work on the electrical system today. The PO tried to rewire it and failed. Its all screwed up. I got most of it working, but thats another issue I think I can figure out.

So what would be a few things to look at?

[Inferno]

It really sounds like a bad electrical connection between the battery and the rest of the bike. Check the battery cables for any and all corrosion. Make sure the thick cables are good all the way to where they connect to the frame and starter solenoid.

Contrary to popular belief, even though the ends of the cables can be fine, the rest of the cable can deteriorate.