86 Maxim (Idle Issues)

When I start my bike (86 XJ700) on choke it starts good and sounds normal, however as the bike warms up the idle goes down and it stalls out, and if I let the choke off it will stall unless I sit there and rev the bike like a mad man.

I tried to adjust the idle screw up on the carb when it's warming up and it seems to be perfect but after riding it a couple of miles I have to readjust the idle screw back down cause the bike will start to idle at around 3500. After I adjust the screw back down the bike performs perfectly until I shut it off for 20 minutes or so, then I have to repeat the entire choke and idle screw process all over.

I can not seem to get this bike to sit at a happy idle.

Also, this morning I noticed that pipes one and two were relatively cold compared to three and four which were blistering hot.

I am going to put new plugs in it, but I feel like something more might be going on.

I recently had the carbs off and washed them in an ultrasonic cleaner and rebuilt them, nothing was touched on the rails so I would assume everything is still in sync just fine.

If anyone can provide some advice I really appreciate it.

 

You "washed them in an ultrasonic cleaner", without stripping them off the rack?
Something doesn't sound right there?

 

Yes I washed the emulsion tubes, jets and the float bowls in the ultrasonic cleaner and washed the rest of the parts outside of the ultrasonic cleaner and replaced the float bowl gaskets, needles and seats.

 

New to you bike? Do you know the history and has it been synced recently? Valves checked for proper clearance? Did you pay special attention to those tiny enrichment jets in the float bowl that are so crucial for cold starting?

 

Doesn'tnsound like starting enrichment is a problem. I suspect the tiny passages from the idle jet to the mixture screw and transition holes may be blocked - carbs out and spray cleaner through them to test is the only answer I fear.
Edit to ask - have you checked the float levels, or now they are on, the fuel level?

 

It was my father's bike, it ran good and then he parked it for about 10 years in a garage, during that time the fuel leaked out. I took the carbs off and changed the oil and air filter, cleaned the gas tank and changed the petcock and fuel meter. I am changing the plugs in it tomorrow but all the pipes are warming up evenly. All of the jets have been cleaned and the little holes in the float bowls were clogged but i got them clean to the point I could blow air through them and run acetone through them and shine light through them, it's kind of a blind spot. I have not checked the valves yet as I just finally got it running yesterday. I was able to ride it and when I adjust the idle to around 1.2k the engines sounds perfect.

Thank you for that tip, it is very well possible, and I also feared pulling the carbs back off. I have not checked the float levels with fuel, but I did measure the floats and they were at factory setting. After 10 years of sitting it's gonna take patience and TLC.

I will post back with a video after I get the front tire back on it to see if that might help.