Help, 86 500 idle

Ok, I have cleaned the carbs a few times and ran techron through a few tanks of gas. I can get the bike to idle off the choke, at around 1300-1500 rpm's BUT when I geto it here, I shut the bike off and tried to start it back up with no luck, On or off the choke. So I had to screw the idle screw back out for it to start back up.

But whith the screw in this position, the bike will not idle off the choke. The choke needs to be about 1/4 to 1/2 way cut off and I can get it to "Idle" around 3K rpms.

Any ideas? do I need to take them out and clean again?

thanks in advance!

 

So use the idle adjustment screw to boost up idle speed when engine is cold, and use it later to lower idle on a hot engine.....that's normal on some bikes!!

I always crank screw in about 3/4 turn everytime after starting and bring choke back to zero as soon as possible.....try it.

 

Did you sync the carbs after they were reinstalled? It sounds like that could be your problem.

 

I seem to have found a happy medium. I got it to start with the choke on, and while it's warm the idle will roam from 1,500 to 3,00 rpm's. So I think I have an air leak or the jets are not fully clen yet. I will leave it like it is and run a few tanks of gas to see if the idle hangs around the high side. hopefully after riding it more, the idle will stay on the high side all the time and I can lower the idle screw to the correct idle rpm's

 

I drove it into work today. The idle stayed steady except for ~3 dips. Other than that it would hold at 3K rpms. I lowered the idle just a bit ( ~2200 ) and it seemes to be holding. I am now leaning toward the cloged main jets working the debris free slowly.....

I made a home made sync tool ( tube / yardstick / motor oil ) and everything looked ok....after the idle gets steady again I will recheck.

 

Put a phillips screwdriver on all 8 clamp bands securing carbs to engine and tighten up any that are loose, since an air leak there can cause your symptoms.....

Have you run some Sea Foam through??

 

It's not the main jets you're after, but the pilot jets (or slow speed circuit). They're the smallest jets in the carb and the most difficult to clean. If you have a jet cleaning tool, use that. If not, pull a strand of wire from it's sheathing and use that. Be very careful not to altar the size of the hole at all. As always, synch when reassembled. It helps to remove the idle mixture screw as well if you haven't already.

 

Ya I tried using tooth brush bristles to glean out the holes, But i guess they did get clogged again. It looks like I will take it all off again and reclean this weekend.

 

As was said before, use a piece of copper wire from a multistrand cable. The copper is softer than the brass and will not enlarge the jet holes.

 

Yeah, I'm not sure if I've seen a tooth brush with bristles long enough to go through a pilot jet, but I'haven't seen everything.

 

i think a copper wire is too weak and suggest steel wire and think it won't enlarge hole if used carefully.....

can you see light through the slow jets?? you need to!!

a toothbrush is useless, exceept on teeth, of course.

 

I was able to see light through the holes. And I blasted cleaner through the ends. But I definitly think they are clogged again. On my ride back home the exhaust started poping again ( lean condition ) and this went away after the last cleaning.

I was thinking about using those little "pipe cleaners" you can get for kids craft time and seeing if the fuzz and wire could fit through the jets to clean them out. Stick the pipe cleaner in one end and pull it out the other, then blast it with cleaner again...

 

If the jets are getting clogged again, what's the condition of your tank/fuel filter? I bet trash/rust from the tank is getting past your fuel filter - or clogging it up.

Use berryman's cleaner to dip your carbs & jets. Make sure they are clear with copper wire. I spray WD-40 into each jet and verify that spray is coming out of every orifice (wear safety glasses).

Also, make sure all your lines are gas lines. I had some rubber hoses laying around that I was sure were gas lines - Nope!

The hose disintegrated from the inside because of the gas. The tiny rubber pieces clogged the fuel filter and caused the bike to stall. And caused the #1 carb float to hang when parked - flooding the combustion chamber with gas - gas leaked into the crankase and even came out the sides of the #1 carb boots.

 

The idle circuit orifices are in the carb body such that you'll never be able to see light through them anyway. Are you sure that you are focusing your attention in the right places? You'll want to remove the idle mixture screws completely and make sure the cleaner and air flows freely through those passages.

 

IT's running perfect! I took off the carbs again.....and 2 of the 4 idle jets were plugged. I re-cleaned all 4 with the help of 24/28 gauge wire. Then I sprayed through all the fuel paths I could find. Upon re-assembaly I made sure that the boots sealed the carbs well.

Once they were back on it started right up, and I was able to put it on idle within about 5 min.....I also placed a fuel filter in line from the tank to the carbs. I checked it after I got it running and a few 1-2mm Gum type objects were in the filter. I am assuming this was the culpret after the other cleanings. But now replacing the fuel filter will be 100X easier than re-cleaning the carbs again....

THANKS to everyone that helped, and offered ideas!

 

Idle Screw

Hi,

Do you know where the idle screw is located on the 84-86 VF500? I cant seem to find mine and my idle is too low, around 800 RPM. It will usually die at stop lights, or I have to hold the throttle open. Any help would be appreciated!

 

It's right in the middle of the carb rack and points toward the front. You have to reach through the side just above the cam cover and just behind the radiator. It's kind of pain, I guess Japanese dudes have smaller hands.