Always rich/I hate carbs

[Ken Talbot]

Yes, I think you will want to drill our the airbox nipples and connect a couple of breather lines. When you said you did not have the breathers hoses connected, what did you do with the two upper nipples between the carbs?

[Snow]

Originally posted by Ken Talbot
what did you do with the two upper nipples between the carbs?

I just have the hoses pointing up towards the tank, hooked up only onto the upper T-fittings on the carbs, the other ends not connected.

[fusionking]

T-Connecters maybe?

I do know one thing, you can swap the t-connectors for fuel and vent and it'll flood over. It will go together that way but they are not the same. BTDT

[Ken Talbot]

Okay, so the hoses were probably venting the way they should have been, even if they were not connected to an airbox.

When you were working on it, did you try tipping the carbs upside-down, with the floats and float valves in place, and try blowing on the fuel supply lines to verify that the fuel flow was being shut off when the floats were "up"?

[Snow]

No, as obvious a check as that sounds, I have not done the blow check - I'll do that first chance I get.

[fusionking]

Vent tee's(the short ones)

What I was tryin' to say if you put the fuel t's where the vent ones go they are too wide and they are blocked off. On mine it caused it to flood over and I was pullin' my hair out for awhile. With your floats set so low it may cause a rich condition instead. Just a suggestion if you don't find yur problem and you tear em back down don't forget this!!! I am sure this happens a LOT. They gotta vent. Idle screws tight and still too rich means something quite significant wouldn't you guys say? Also if I remember right this only blocks venting on 2 out of 4 carbs.

[stevec5000]

Check the float height with tubing!

I just replaced my leaky float valves with new ones from partsnmore.com and had a similar problem with it being too rich. With the float height adjusted to spec, when I turned on the gas it overflowed and came gushing out of the carbs all over the place. After a lot of headscratching I found the new needle valves have a weaker spring under the little plunger. The floats would go all the way up and hit the top of the chamber when fuel was turned on without closing the needle valves all the way. I had to adjust the tang on the floats quite a bit to get the needle valve to close all the way before the floats hit the top of the chamber. Check by pushing the floats down to see that they don't hit the top of the chamber. Instead of measuring the float height, use the clear tubing test to check the fuel height in the float bowl. It should be 3mm below the gasket seam at the top.

[Snow]

I got my carb kits from motorcyclecarbs.com btw - I checked the float valves/needles last night at the level I had set the floats (very low/lean, actually way out of spec) and they sealed just fine when flipped upside down and I tried to blow air in (hate the taste of gas).

So, then I reset the floats to factory spec height of 25.7mm (or close as I could get) and then tested the valves again - still holding just fine.

Then I swapped the 45 pilots (these are 78 carbs) with my other nearly new 42.5 pilots and put the carbs back on the bike.

Now she doesn't smoke at idle, but does when you hit the throttle. I have just come up with the brilliant idea of swapping my needle jets (no sarcasm, really) with ones that are known good from an 80/81 set of carbs I have torn apart. They are different I know, but I figure since all the years use the same needles the worst that could happen is that it won't work right.

So, that is what I am doing after work today. Oh, and I am picking up some new plugs as mine are completely black, but dry.

[Snow]

Well, that definately did not work. Ran super rich, so I pulled my 137's and put in 112.5's I had...that was waaayy too lean and idled at 5500rpm...

Suggestions whule I go to dinner break?

[skids]

I hope you drilled out the airbox nipples and installed the hoses during the test. Try going back to using the original jet needles and slides. Make sure the main air jet is clean. That is the one in the inlet bell at 4 o'clock. Go down a couple of sizes in the main jets and use the 42.5 pilots. At least that is what I would try... BUT maybe you have been through that iteration already.

Originally posted by Snow
Well, that definately did not work. Ran super rich, so I pulled my 137's and put in 112.5's I had...that was waaayy too lean and idled at 5500rpm...

Suggestions whule I go to dinner break?

[Snow]

Alright, I decided to take skid's advice last night. Spent several hours (yeah, I'm slow) and had the carbs set back like 78's except the pilot jet set to 42.5. Also, drilled out the airbox nipples - they apparently weren't filled brass as I thought, they actually were hollow brass tubes filled with some glue type material, hopefully they are not more airjets...

I also did the pickup coil wire fix with liquide electrical tape just to make sure - a few months ago, I managed to put my left cover on with the wires protruding and just taped everything up after verifying all wires still were connected...yeah, I know, dumb.

So, after all that work, I tried to start her and wouldn't you know it - the battery went dead...argh! So, put her on the 1amp charger last night and gonna go see if she'll start today.

[Snow]

When it rains, its pours...the story of my and everyone else's lives.

Today, I redid my pickup coil wire fix. Today and yesterday I noticed that my spark has been erratic at best. Finally, while on the phone to my brother that helped me strip the bike to frame and rebuild it (and put a big bore kit in recently), he suggested I try unplugging the emergency shutoff switch. Back during the rebuild, I had inadvertantly put the switch in upside down...needless to say, we had no spark and it took us a couple hours to track down the problem.

well, I unplugged it and voila! I have consistent good spark again! Now, if only my battery wasn't dead from several days of trying to make it run :/

[Snow]

The bike ran, not well, but ran after doing all of that - then I decided that the only fuel metering jets left that haven't been replaced are the emulsion tubes. So, to test a theory of wether they might be worn out of spec (could happen within 5,000 miles according to factory-pro), I lowered my jet needles as far as they would go (highest clip positon).

Now she is running almost perfectly from idle-6000 rpm (aside from still smoking some) after syncing and re-colortuning. I think I may need to throw a larger main jet back in b/c I have MAC 4-2 exhaust and K&N stock-type filter and she just runs out of steam right around 6,000 rpm. I've got 140's and 145's I can try.

So, I believe I need to replace my needle jets (emulsion tubes) so I have contacted factory pro and am working on getting them sample needle jet for both 78/79 and 80/81 carbs.

Once they have the samples, they can make new needle jets for whoever wants them.

[skids]

The emulsion tubes are fairly rugged. I suppose they could wear out, but I don't know how. The jet that feeds them is the pressed-in main air jet in the inlet bell of the carb. Those things could get plugged and cause a rich condition...

Take a peek at the bottom schematic:
http://home.earthlink.net/~sidskids/carbs.gif

It is like the analogy of the hole in the side of the soda straw. Well, the main air jet supplies the air to the emulsion tube. If it is plugged, you get more "soda" and less foam. I am not sure if this makes sense, but it seems to.

Originally posted by Snow
So, I believe I need to replace my needle jets (emulsion tubes) so I have contacted factory pro and am working on getting them sample needle jet for both 78/79 and 80/81 carbs.

Once they have the samples, they can make new needle jets for whoever wants them.

[Snow]

How would I make sure the main air jets are all clear? Do I need to get a special carb cleaning wire kit?