82 XJ500 Quit running (Fuel issue?)

Hello everyone,

I've been working on my 1982 XJ550 for the last couple of months. This is my first time working on something like this, and I definitely wouldn't consider myself mechanically inclined, so please forgive my shortcomings. The good news is that she's alive and running! Or, well, she was for three days...

We had a nice stretch of weather last week, so after I got it running, I was excited and drove it around to test it, making sure everything was working since I've done a lot of work on it. I was happy it was running. The first day was awesome; the bike felt great, nothing out of the blue. The second day felt great too, though I noticed a low-volume burble/popping noise when decelerating. I didn't think too much of it until after the bike stopped running. I checked the plugs, and they are sooty and black, so I believe it's running rich.

On the third day, I was at a stop sign close to my house when I noticed a slow increase in idle RPM, from 1.5 to around 2.5/3K (air leak?). When I got home, the bike dropped to low RPMs, stuttered a bit, and died. It wouldn't start back up. It will start with starter fluid, but it's not starting on its own gas, and I cannot figure out why. It was running fine the day before.

I've taken the carbs out again and cleaned them to be sure. There are no crimps in the fuel lines, and fuel is getting to the carb bowls. (I just cleaned the tank and filled it with fresh gas.) The plugs are basically brand new, but I cleaned them off. I'm going to get new ones. Can someone confirm the correct plugs for an '82 550 Maxim, please?

Any help would be appreciated because I am stumped.

Thank you!

 

That does sound like running out of fuel, much like when going from on to needing to switch to reserve, so yes running out of gas. Or a venting issue on the gas cap, which will also inhibit fuel flow

So if you have plenty of fuel in the tank then check the vacuum petcock is functioning correctly , the fuel filter (if external) is not clogged and is the correct type, and the gas cap is venting properly

And a good description of "cleaned carbs" is always helpful so others are not guessing to what level that was done

 

Cleaned the tank?? Does that mean the tank had stuff in it? Rust or other stuff? Did yo up a in-line fuel filter between the tank and the carbs? If not, next time please do so. We work so hard at cleaning them carbs and a simple in-line filter will really help out keeping them clean.

The three day effect as I call it seems to come from fuel issue to the carbs. If a bike has been sitting for a time and had some type of dried fuel in the tank, lines carbs or all of them. The new fuel will get in there and with movement brake up the old nasty stuff and it will find it's way to the carbs. The jets and passages in the carbs are so small and that little one in the bottom of the float gets dirty or plugged all the time.

If you are taking the time to removed the carbs and going over them again, pls put a filter on the fuel line, might not have to take them off as often.

 

Thanks for the reply!

Sorry I was rushing when writing and didn't explain better, Yes the tank was honestly pretty good shape when i got it but the fuel was old and tank still did have minor debris/crud in it so its been flushed out and is looking great now. My apologies again but I forgot to mention I did install a fuel filter on the bike the first time i took the carbs out and all the fuel lines are new, so when it was running the whole "circuit" was clean (Fresh fuel In Flushed/Clean Tank -> New Fuel lines -> New Fuel Filter -> Clean Carbs (Church of clean). Since then I've taken the carbs out again for a cleaning but had no luck firing up when i re-installed them. Will be pulling the carbs and going over them again cause I can't think what else would be causing it.

Thanks again

 

Go back to the basics. Make sure you have good spark to all the plugs. Take a look at the plug wire ends as they go into the caps. A lot of times they turn green and will not make good contact. Most of us just chop a small part off the end of the plug wires (making sure the will still reach) and this normally will removed the green.

Good battery? Make sure you keep up with the battery, good charging system is working like it should. I know, hard to check now that it is not running like it should. I keep a spare car battery around with jumper cables for these jobs. That way the little bike battery I don't really have to worry about going dead or not having enough power to make good spark.

Keep up with it and do your trouble shooting. Have you checked and cleaned all the fuses yet? Most replace the OEM fuse holder with a newer micro blade type and then you will not have to worry about them buss fuses any longer.