1982 xs650 j heritage not cranking

Greetings and salutations. I've had this bike for quite a few years now, but never had the time or the know-how to work on it. I'll try to describe what I have done and what is currently happening.

I updated the fuses to the atc-type because the glass type were constantly blowing. Electrical system is all reading correct resistance and voltage, except the starter cutoff relay which I have removed. I haven't gone any further than just unplugging the relay(yes, I plan for a permanent solution, just not immediately).

As far as the fuel system goes I cleaned out the tank and the carburetors. The carbs are mikuni and are not connected (choke, air/gas mixture screw are actuated on each individual carb) The petcock is set to PRI because I can't figure out where the vacuum tube goes to from the petcock. That brings about my first question - where does the vacuum tube from the petcock connect to?

More importantly, and my final question - I had the bike firing on one cylinder last week. Found out it was a carb issue because I switched the carbs and the opposite cylinder fired right up. I cleaned the carbs out until they were clean enough to eat out of and now the bike won't ignite at all. Nothing was changed in the electrical system and the only thing I did to the carbs was clean them. Does anyone know what could have happened to make my bike decide it doesn't like cleaner carbs?

I really appreciate your help, consideration, and patience.

Welcome to the forum, tdd5024.
(Well, after 1-1/2 years anyways)

Sounds like you have Mikuni VM series carbs on your 1982 SJ?

This is one of those times when I'd pull and read the plugs, see if they're dry or wet, or fouled...

Yes sir, I've been following the posts to fix as many things on my own without bugging you guys.

That's is correct, mikuni vm series carbs.

When the bike was running on one cylinder the running side plug looked fine and the opposite side was wet with fuel.

The petcock vacuum line connected to a brass tube molded into the factory intake manifolds (the other side was capped).

Yes plugs, wet or dry? how's the the spark? Stock TCI iggy yet?
pics always help.

So is petcock vacuum tube unusable?
Plugs are now wet. Spark is good, plugs are newly gapped. Stock TCI is working fine, as far as I know. It could be the thing that went out in the past week, but my gut is telling me it has to do with the carbs. My neighbor mentioned it might be loose carb boots allowing an air leak. I'm going to grab some sealer and throw that on there to see if that changes anything. I would take pics but my phone is off being worked on with HTC.

Don't use sealer. Get new boot gaskets, and when carb boots are warm, tighten the clamps a little more. Use unlit propane torch to find air leak if tightening don't do it.
The bs34's are a good carb, you just have to make them that way.
As far as the ignition is concerned, the later years used a wasted spark, if one side is fireing, so is the other side. (Or trying)You cant check the connection of the plug wire at the coil, but you can unscrew the plug cap from the plug wire. Unscrew that and check the connection there.

Angus, took your advice and bought new. Put them on and I'm still not getting ignition. Somewhat lost on where to go from here. I have some pics below, finally got my phone back!

Plug on left was wet after a few attempts, the right was just getting damp

That right carb looks like its uneven in the carb holder or manifold/boot. The top of the carb appears to be running out of room where it's almost touching the engine. Those boots/manifolds go on one way and can be easily swapped side to side and put on upside down.....especially when you're using individual carbs as opposed to linked carbs. Linked carbs would show you right off if the boots were swapped or upside down. Might look into that.
I'll add that the left carb looks ok, but that right carb ain't straight......

And the battery is fully charged?
How did you test the spark?

A breakthrough! Here is how it all came together. The new carb boots had air inlets coming off of them, so I plugged them with a piece of hose and a screw temporarily. Then as I was scratching my head on what to do next I checked the spark plugs and one side wasn't firing as well as the other. Spent the 5 bucks to replace them both and she fired right up. I'm getting some sputtering and air popping on the left side now. Any recommendations? It sat idling for ten minutes and I rode it around the neighborhood a few times.

If the carb boots in the picture have the barbs on them (air inlet), then they are installed backwards. The barb should be outside.

yeah that angle does look a bit off.

OK, got them switched around. It's still popping air on the left side. And what line do you have going into your barbs Gary?

Working vacuum petcocks.

So that is where the vacuum line from the petcock goes? Is there anything else I need to do to make it work?