Carburator

[mattie]

I'm having problems with trying to keep my 1986 vt700c shadow running. It sat for a couple of years without running, and I took the carbs apart and cleaned everything. It does start but only idles on choke once I take off choke it dies..Any help would be great thanks. Mattie

[nrburkett]

have you tried running some seafoam through it?

[mattie]

Never heard of seafoam.. I changed the plugs completely cleaned the carb, changed all fluids,fuel filter etc. I can somewhat keep it running off choke with the throttle at full but is erratic. aroun 1500-2000 rpm but real rough. when choked it runs smooth around 800-1000 rpm?

[MarkC]

When you took the carbs apart its sounds like you missed something in the pilot circuit. The pilot circuit is the smallest of teh fuel/air ciruits, its the hardest to clean out. And any time I have ran across your problem, the solution has been in the pilot ciruit.
MarkC

[mattie]

The pilot circuit,I will have to look that up. I'm just a backyard mechanic when I have time, My next question would be given the symptoms does it sound like the issues are in the carbs? And should I get a rebuild kit and or a jet kit also?

[mattie]

Cant seem to find were the pilot circut is located, some help would be great.

[oldbike]

The pilot jet is the smaller of the removable jets in the float chamber. Make sure air can pass through the jet, hold it up to the light and you should see the tiny hole. If not either rod it out with a small wire or get new ones, and spray the passages in the carb with carb cleaner. Make sure to wear glasses during the spraying, it burns the eyes badly (prior experience). I had to do the same with mine.

[mattie]

I really thought I cleaned that tiny jet out, I did clean the carbs twice! both of them and still had the same erratic idle. I was very tho row in cleaning and brushing w/ tooth brush. Thank you for the info and will clean and rebuild kit.. any other info would be great guys..

[Easy Rider 2]

Originally Posted by mattie

I really thought I cleaned that tiny jet out, I did clean the carbs twice! both of them and still had the same erratic idle.

Before you tear the carbs apart yet a third time, you might want to inspect for a vacume leak. Are the boots going into the engine tight and not split or cracked? Vacume line to petcock connected and air filters in place?

The carbs may be WAY out of sync. now too.

[tubes_rock]

MarkC is right on (not that we ever doubt that!) when he said it was your pilot circuit.

When you took the carbs apart, did you notice a screw on each carb (on the outward-facing side of each) that when unscrewed is a needle valve?

If you don't see them, then it's because they're capped over. Honda set them and capped then at the factory to prevent you from tinkering with them. The downside is that they need to be tinkered with right now.

Fear not, you don't have to take the carbs off the bike. Again. Those suckers are a pain to get off this model!

I'll PM Lang, who had a great picture of the small cap that you need to pull off each carb to get to the screw. Hopefully he's around has still has the great picture that he took that shows where it is.

You can pull those caps off easy enough. Get a small (#6) self-tapping sheet metal screw. Not the kind that had it's own built-in drill bit at the end, just the regular kind that looks like a wood screw.

Take a 1/16 or 3/32" drill bit, and wrap a few wraps of masking tape 1/8" from the point. Use a small nail to center-punch the cap on each carb, to prevent your drill bit from walking, and drill a hole in the cap. The masking tape will prevent you from drilling too far.

Now, screw that sheet metal screw into the cap just enough to get it grab well, and pull it out. The cap should pop out, revealing the pilot air screw.

Unscrew the screw from each carb, and while protecting the engine from any spray, use the straw from a can of carb cleaner to clean the hole out good, and clean the screw. There's an o-ring, a spring and a small steel washer in that hole, so gently take them out before going to town with the cleaning. if you loose those, you're sunk without buying a $50 rebuilt kit.

Now, turn the screw back in until it gently seats in each carb. Then back it out 3.25 turns.

If you're bike doesn't run like a scalded cat now, you're probably looking at pulling the carbs off again and really cleaning them good.

--Justin