only idles on choke

[TexinMaine]

Have a 78 that has been sitting for a while. 3 of the needle jets were stuck. Tore carb apart, cleqned everything with carb cleener and blew dry with compressed air, diaphragms were in good shape and was careful aligning them when I put carbs back together. Did the bench sync by adjusting the butterflies to dissect the first little hole on the intake. Got it back on the bike and it will start on full choke and will even increase idle as it warms up but as soon as I touch throttle or take off choke it dies. Sorry if this is old news but tablet for some reason will not let me do a search. Thanks in advance.

Tex

[natemoen]

Going to have to do some more cleaning and pay special attention to the idle circuit.

[Meista007]

Have a 78 that has been sitting for a while. 3 of the needle jets were stuck. Tore carb apart, cleqned everything with carb cleener and blew dry with compressed air, diaphragms were in good shape and was careful aligning them when I put carbs back together. Did the bench sync by adjusting the butterflies to dissect the first little hole on the intake. Got it back on the bike and it will start on full choke and will even increase idle as it warms up but as soon as I touch throttle or take off choke it dies. Sorry if this is old news but tablet for some reason will not let me do a search. Thanks in advance.

Tex

I'm no expert on the carb issue but I have solved the searching from a tablet issue!
You have to click search then go into Advanced Search.

That should solve one of your issues...

[jetmechmarty]

+1. You have failed to get the carburetors clean. The idle circuits are not functioning. In warm weather, you should be able to close the choke almost immediately.

[motoman]

Going to have to do some more cleaning and pay special attention to the idle circuit.

+1.......Nate's dead-on. I would seriously consider inspecting down inside each pilot jet with a magnifying glass and good light,DAMHIK. ALSO, make sure that tiny atomizing hole in bottom of pilot jets is open.
FWIW, if you didn't remove the emulsion tubes before cleaning carbs, your efforts were wasted from the get-go.

[TexinMaine]

Ha! So it turns out that my problems were of my own doing. I was rereading about carb syncing and discovered I had mistakingly used the idler screw as part of the adjustment and the idle turned completely off. So 5 or6 turns and now it idles at about 1100 rpm. Now it still seems to run a bit rough and as I give it throttle will backfire a bit, so will vacuum syncing the carbs help solve this problem? Lol, after a short ride it also appears that I have no rear brakes which will be the next project once I get it running smooth.

[D0wn5h1ft]

Ha! So it turns out that my problems were of my own doing. I was rereading about carb syncing and discovered I had mistakingly used the idler screw as part of the adjustment and the idle turned completely off. So 5 or6 turns and now it idles at about 1100 rpm. Now it still seems to run a bit rough and as I give it throttle will backfire a bit, so will vacuum syncing the carbs help solve this problem? Lol, after a short ride it also appears that I have no rear brakes which will be the next project once I get it running smooth.

5 or 6 turns out is WAY too much. From what I understand, the idle mixture screws saturate at around 4 turns out. You're waaayyy too rich and that's where the back firing comes from. You have unspent gas in your exhaust that keeps detonating from the heat. If you have an open exhaust (striaght pipes or just a couple of baffles) you'll see it shooting flames out of the back

Turn those idle mixtures screws all the way in (DO NOT tighten them down, just so they're seated and "zeroed" out) and then turn them out 3 turns. It will run pretty good at this setting and gives you a starting point. The only way to get them perfect is by doing a plug reading and dial them in from there. After this is done (and only after) do a vacuum sync. Otherwise you'll be chasing your tail and have to re-sync after every idle mixture screw setting change.

Normal idle screw setting are between 2-4 turns out with 2 and 4 being extremes. I believe mine is set comfortably at 3-1/2 turns out because I like it to be a little rich at idle to keep things cool in traffic.

[donebysunday]

As D0wn5h1ft said do not turn those idle screws in tight, put some oil down in there and turn them back and forth until they turn freely. It's then easier to feel them lightly bottom out, LIGHTLY ! 3 1/2 turns out from lightly seated is what mine are set at.

[TexinMaine]

There is just the one knob thing on the back. Perhaps I used the wrong term for it? It is on the side closest to the air box.

[D0wn5h1ft]

Ah, got confused. I haven't her the idle adjustment referred to in numbers of turns before so I thought you were talking about your idle mixture. Even so, those idle mixture screws are still most likely your problem. What did you set them to when you got them "unstuck"?

[TexinMaine]

I had read about a "bench sync" and adjusted the butterflies so that they bisected the first air intake hole.

[TexinMaine]

Sorry I forgot to mention a Thank You to Meista007 for the search tip on my tablet.

[cajun31]

Go back through the cleaning process

Read this thread a few times .... http://www.xs11.com/forum/showthread.php?t=36017 then dismantle the carbs and do a thorough cleaning.

I say read the thread several times to make sure you understand where each part is. That way when someone tells you something else to check you will know what they are talking about. I too believe that part of your problem is the idle mixture screws, however from your responses I am not sure you knew where they were exactly. Be careful when messing with them. If you over tighten them when turning them in you can over do it and the tips break off. That too can be fixed, however it is a bit more of a bear and you then have the problem of needing new screws. there is also a small spring and a rubber o ring down in there.

[donebysunday]

cajun31, there is also a small spring and a rubber o ring down in there.

As well as a tiny washer, the spring goes on first next the washer and the O-ring. The O-ring develops a shape to it, look close the beveled side goes on towards the carb the flat side towards the washer.
I made a tiny bend in a paper clip then cut it off and filed it until it had just enough to catch onto the O-ring and washer which normally end up staying in the carb.
If you find you need/want to inspect these work in a deep pan so as not to loose these parts.
I lost one O-ring and washer and made my own then found on another set the PO did not have them in there, I made some more. If you find you have cracked or lost parts I can explain how to make them.

[mack]

Pilot Tower

As soon as the enrichement plunger is pushed in it opens the pilot tower circuit which feeds both the idled and pilot circuits. That tower is plugged in probably all the carbs. As stated you need to clean those carbs properly.
When completed, turn the idle screws out three turns and bench sync with a bread tie or the smallest diameter guitar string. This will get it close enough to start and idle. From there you can sync it and ride a few miles then check your plugs. Adjust the idles to your plugs and re-sync. Then ride that dude like you stole it!