The bike seems to be running very rich even though I haven't changed anything lately. I rebuilt the carb around 6 months ago and it ran great using the stock .50 slow jet and 170 main jet.

After a few months it got sluggish and I isolated the problem to air intake at the manifold compliance fitting by spraying wd40 where the carb mounts up, and had the engine speed increase. So I applied locktite and tightened it to spec, and it ran great once again.

Now a few months later it is really hard starting and running poorly at idle. I check the idle adjustments and the idle-mixture setting and I find that I need to adjust the idle-mixture screw until it is at the max and loosing resistance from the spring. The engine speed increased the whole time. Next I ordered the .52 slow jet. In the meantime I found that one of the spark plug wires looked bad, it was corroded on the conductor that sits on the rear plug. I replaced the wires, checked the plugs...they were fouled, replaced them too. Did the electrical checks for the coil, ignition module and stator, they all check good.

I install the new .52 jet and same thing, the engine speed increases through the whole range and it runs best when it is beyond the resistance of the spring. I took it for a ride and it feels good there but it looks like I still need to go up a jet size or two to hopefully get in range of the spring load. (or more?)

I am wondering if there is a different problem I am compensating for that I need to find. Does that point to something clogged in the carb, or anybody have any other ideas?

 

Those compliance fittings were not so great from the factory. Mine (87) cracked at under 15,000 miles. Replacements seem to hold up much better. If those are the originals, you might consider replacing them. At least get a bright flashlight and take off whatever you have to and inspect them very carefully, as well as the hose clamps holding all that stuff. They will crack on the backside (shifter side) and are bad to leak at the flange where they bolt to the head.

Also, considering you were sorta "there" already and from your symptoms, make sure your VOES is working. It's easy to break the ground wire at the terminal end. That could also cause the symptoms you mentioned.

Remember - it was running good as it was setup before, so changing the setup probably isn't the remedy for it's not running right now...

 

Thanks for the suggestions. Yes, many years I had the compliance fitting replaced with the upgrade that was available at the time. I sprayed the area with WD40 today but it didn't change the engine rpms so I think I am ok there.

As for the VOES, the ground wire seems solid. I haven't followed the other wire back...it goes to the ignition module, doesn't it? I'll need to check that out. The vaccuum hose seemed solid on the voes side but a little loose fitting at the carb. So I picked up some new hose from the automotive store. I'll put it on in the a.m. and see what it does.

 

Yes, the other end goes to the module and is connected under the tank.

Hopefully the hose will take care of it. You can check VOES operation by starting it and warm until it will idle, then pinch the voes to manifold hose. May take 2-3 seconds, but the engine should slow to about half of normal idle rpms.

 

my 85 was running poorly last summer. it just didn't want to run right. it seemed sluggish. i did a lot of ignition parts replacement. it ended up being the ignition circuit breaker that was starting to go south. i changed that and everything was fine. if i remember correctly the breakers are 15 amp. there are 3 breakers on the 85. ignition, lights and accessories. i replaced all 3 of them. there is also a main breaker so that makes 4 breakers total. i don't remember what the amps for the main breaker is. if they never were replaced i would change all 4 of them.i got them at an auto parts store. about $8 each.

 

their are seals on the butterfly shaft that are not replacable,sounds like yours are going south.
kirby

 

First off, I guess I should correct the title to this thread...it seems that if the bike runs better by opening up the a/f screw then it must be running lean and I am enrichening as I open the screw. "RUNNING LEAN"

Anyway, I checked the VOES connections and replaced the vaccuum hose but it didn't change anything. Also checked and cleaned electrical connections from the battery, through the solenoid, starter switch and breakers, though I did not replace the breakers yet. Also, retightened the carb mounting bolts. The bike still runs the same, running best when the idle mixture needle is past the tension of the spring.

I decided to open up the carb and remove the slow jet to blow compressed air through just in case there was any blockage. I think I made a slight mistake of removing the mixture needle and spring first because I guess there is supposed to be a washer and o-ring seated at the bottom and I am not sure if I blew them out. Bummer.
I might meed to remove the carb to check it out unless I find some better way.

 

CV or an S&S your next step Those chock springs were also a big problem HD never had replacements

 

do yourself a favor and replace the carb,CV`s are good carbs and their a dime a dozen.the best thing i can say about a butterfly kehin is "they will work"
kirby

 

Uhhhh...

I wasn't thinking or paying attention, else I've lapsed into a coma and it has been a number of years since I had my hands on one, but if memory serves me, the stock carb (butterfly 84 - 89) doesn't have an idle mixture screw adjustment.

So let's start over and tell us exactly which screw you're turning and positively identify the carb....