1981 Yamaha XJ650 Maxim starts then quits.

[SlayerJohn]

I am calling out and pleading with the smart ones out there to help me out. Some good sound advice would be appreciated. I get my bike running, and then four minutes later, it stops. And it has to sit for hours before it can restart again. I replaced and then checked the sparkplugs, replaced the corner connectors from the ignition wires to the plugs, and spent 500 bucks getting the carbs fixed. Still, as I let it run for four minutes, it seems to dwindle down and bog out and then won't restart. I rechecked the sparkplugs, they're fine. I even get a shock when I check the ignition wires, so those are ok obviously. Could it be the solenoids underneath the gas tank? Wires? Please help this poor 4 wheel driver out? I need to get out and ride. Thanks for reading this too.

[storysunfolding]

Try it with the gas cap off and report back.

[totalmotorcycle]

I had a 82' Seca, same engine and electronics. Do storysunfolding's suggestion also check to see if you have gas flow in your gas line. 4 minutes of idle (or revving) might just use up the gas in the gas line (get a clear gas line between the carbs and the petcock so you can see what's happening) and your not getting more into the carbs. Also it might be your fuel petcock if that's the case. OR if you have a fuel filter, try taking it out and see if it's gummed up.

If not the above two, there are a few electrical items I could suggest testing next. Is this is "new" bike for you? Have you had it running in the past on the road? If so, did this "just happen" now or was it a slow deteriorating condition over time?

Mike

[SlayerJohn]

Thank you for the info, I will do that after work tomorrow, go buy a couple clear gas lines. There are two gas lines from the petcock. The one bottom gasline flows freely, and then there is a skinnier nipple that goes out to somewhere else. Do I need to put clear ones on both? I will do that anyhow, so I can see what's happening. There is nothing open right now, I will go to the motorcycle shop and ask for some clear hoses after work tomorrow. Also, regarding past usage and deterioration, I was riding the bike last summer, but then I had a petcock leak, I sealed the leak myself but it was not the greatest job, but it stopped the leak, and then a month later, maybe less, it started doing this. Could it be I could just have to replace the petcock?

[Johnj]

Did you remove the petcock when you sealed the tank?

[totalmotorcycle]

Quick post --

You don't need to buy a clear line for the skinny one, it's the vaccum line from the petcock to the engine block. If you had petcock issues then buying a $4 clear line will show you if the gas if flowing. When you get back try the simplest things first, then the cheapest next, etc..

Remember the triangle:

Fuel, Spark and Air in the proper mixture.

Mike

[Deadlever]

... I was riding the bike last summer, but then I had a petcock leak, I sealed the leak myself but it was not the greatest job, but it stopped the leak, and then a month later, maybe less, it started doing this. Could it be I could just have to replace the petcock?

I'd start there: You may have sealed your line or the vacuum shutoff while repairing the petcock leak. On the Maxim, you can switch the petcock to bypass the vacuum line in order to fill the float bowls (positioned pointing to the rear). Try running it that way. If it runs, then you have a vacuum line problem, not a delivery problem.

Sorry about all the money spent so far, but Administrator is correct: start cheap and then work your way out of the problem.

[SlayerJohn]

Well, I got some clear line, wasn't the perfect size, saw that it wasn't filling properly with fuel, tried running it, ran good then stopped abruptly all of a sudden. Did this three times. Then I was frustrated and decided to give up on the bike, and I reconnected the normal fuel line and vacuum hose, started it up with a charge, and then all of a sudden, it was running good. And kept running, and kept running. I think I had a vacuum leak. Could that have been possible? Anyways, I just got back from my third ride heehee. Glad to back on two wheels once again. Whatever I did, it must have been reconnected more properly or something. I can't say for sure, but it runs great. The idle wont go down below about 1,800 RPM for some reason. I don't mind running at high idle, at least it runs. I turn the idle screw back and no response, but I'm afraid to break it down now that it's running. Signed: One very happy rider once again! John.