'82 Yamaha 750

[k1ng0fb0r3d0m]

Alright, dad's bike is having some issues. (As if that wasn't obvious since I'm posting here.)

Anyway, it's an '82 Yamaha XV750J bike with 45,972 miles on it. Wouldn't start yesterday at all. He tried again today and got it to fire... and backfire a couple times. Nothing serious, just a couple pops. Started spitting a little white smoke from the tailpipes (and the rest of the exhaust which needs to be replaced), smoke went away for a bit, then came back even worse. Well, I stepped inside for a bit and when I came back inside he had rolled it back towards the house, leaving a trail of oil behind him. Apparently one of hte overflow hoses was pouring oil out of it, and one of the two carbs hoses (believe it was the air intake, the biggest one on it) had popped off. Not ripped, not split, just came off, no damage to the hose. There was oil coating the inside of the hose/tube and it dripped a little down over the engine too. Nothing looks to be damaged, just the hose pouring out oil and the other popping off.

I will throw this in, he has a tendency to leave the petcock on prime instead of on, like you're supposed to. Don't know if that'll have anything to do with it, but who knows.

[Clint]

How long since it ran last or was used regularly? It's normal for some smoking from seepage and all. Did it stay running? Leaving the petcock on prime will often flood the carbs, and if the float valves are leaky it could fill the engine with gas, causing hydrolock.

[k1ng0fb0r3d0m]

It hasn't been too long since it last ran. I can't tell ya exactly when, but no more than a couple/few months ago. It's the wonderful state of Missery so he can ride a few times during the "winter."

Was chatting with a friend over AIM and he suggested to take the spark plugs out and crank the engine over a few times to try to rid the cylinder of excess fuel. If I were to do that, and re-attach the hose of course, you think it'd be safe to try starting her up again?

Oh yeah, it ran for at least a minute or two before she died on us. Not actually sure if she died either, dad might've killed it, I walked inside for a bit and didn't think to ask.

[Clint]

I'd consider changing the oil, too. If it has gas in it....

Keep an extinguisher nearby.

[k1ng0fb0r3d0m]

I tried turning it over without the plugs. Nothing came out, though you could see plenty in one.

I did it one side at a time since the plugs are on opposite sides, when I took the back plug out it actually started.. put it back in, no go.

It started when I first went out and gave it a shot too... no idea.

I have a feeling the back cylinder isn't firing though, after it ran, it was just the front cylinder's exhaust and block that was warm, the back one was cool as could be. Plugs look fine, just got to check and make sure they're getting spark. I feel dumb for asking, and I should know... but how to check for spark? Besides holding it, lol.

Probably should adjust the air/fuel ratio too, but I can't find the screw on either of the carbs. Also going to check the air filter real quick.

[Clint]

Pull the plug and reattach the wire. Lay it next to the block so the spark can ground. Crank the motor. You should be able to see the spark.

Don't do it with gas vapors around!

[k1ng0fb0r3d0m]

Originally Posted by RowdyRed94

Pull the plug and reattach the wire. Lay it next to the block so the spark can ground. Crank the motor. You should be able to see the spark.

Don't do it with gas vapors around!

Well, tried her again after charging up the battery, started up. Yet again though, really low idle and then dies, especially if you twist the throttle at all.

It's getting spark, no idea. Could it be caused by the exhaust? I know it's old and pretty much shot anyway.

EDIT: Also figured that I'd say that when I checked the air filter, there was oil coating practically everything. Filter was fine except for one spot, the bottommost spot, that had oil spots all over it.