Is this making sense

Ok got the Sporty back together and put a few miles on her. Noticed that if I pull the choke/enricher while she is warm she runs like a bat out of hell. Takes fuel, no hickups or backfires. The vibration will cause the choke to return to the closed position and at about the half way in mark she starts coughing a bit and getting sluggish. Does it make sense that my main jet is too small or the needle is too low? If I were to give the needle a notch more room or go to a larger jet, wouldn't that be the same as adding more fuel through the enricher circuit? AND yes for those that recall this is what brought me to BT in the first place LOL. Full circle now huh LOL.

Could be an intake air leak. With your engine warmed up and idling, spray a little quick start, WD-40,brake cleaner,or a guy told me this but I never tried it,he used a propane torch unlit.Spray around the intake manifold and carb/manifold mount. careful not to let any go in thru the carb itself. If the idle changes when you do this means you have an air leak. Try that first before gettin into the carb

Assuming that by "just put back together" you mean no changes to the existing setup (carb, cams, etc.) then I'd 2nd what "Lucifer" said about an intake manifold leak. Could be where the manifold meets either or both heads; could be the seal where the carb meets the intake manifold, but any intake leak would cause the engine to run better with the enrichener pulled out.

I don't understand why you'd use the enricher when the engine is warm anyway, unless it's just for a test. Doesn't it risk ruining the spark plugs?

Does it run OK when not pulled out. My Sporty just takes a looooong time to warm up. If I push in the enricher too soon it starts stalling. Good luck.

All the gaskets are new (well from when I started fighting this but no miles or hours on them). The intake had no leaks at the jugs prior to the redo and was not removed from the bike during the redo. This was a sick puppy when I got it and I fought it for a long time before I could keep it running. Atleast now I can ride it, it is just annoying, and wrong I am sure.

I have totally rebuilt this carb, added the EZJust screw, and fiddled with the jets a billion times now. I put it back to factory specs and started from there. By adjusting the needle height (main jet) I got it to this point, which when I parked her I was happy to be on it at all. Now with a long trip coming up I want it "right" not ridable.

Pulling the choke while she was hot was a case of WTF I have tried everything else. That is when I discovered she ran 100% better with the choke out. As for fouling plugs, hang those I will ruin a dozen sets of plugs if that is what it takes to figure this thing out LOL. That is a CHEAP price to pay to get ol girl where she needs to be. The really bad part is it don't really appear the plugs are too far from spec when pulled :witsend: . Now that I REALLY don't understand.

OH Yeah I didn't change the petcock, it is all factory and the vacuum line is hooked up and has no signs of damage.

I appreciate the replies and help, and will go looking for leaks again.

Thanks Chuck, basically you are saying I was making sense then LOL. I REALLY didn't want to tear into that carb again before I made sure I wasn't just being goofy LOL.

Baseline for an 883 is 42 slow, 165 main & 2.5 turns out on the idle mixture screw & if you have to go much more than 1/4 turn either way, something's wrong. Intake leak or to big a slow jet are common reasons.

Up thru '03, the stock needle was usually the cause of the "carb farts" & the infamous N65C from a 1988 XL1200 is a great replacement, but from what I've seen, the needle that comes in '04-up Sportsters works fine as-is, although a few have shimmed it with a brass washer.

Yes, the '04-up bikes have the newer XB style heads, but the 883's have the same combustion chambers & valve sizes as earlier models, so although the baseline for a 1200 changed, it did not for an 883.

It's possible you might need a larger main, but get the low end right 1st, as the main has virtually nothing to do with gettting the bike to start easily, idle right & run around town.

Thanks Art. Interesting facts there. I love learning more about my bike.

Mine is an 05 so it falls into 04-up. I was thinking I had a 45 idle jet but it well may be a 42 (long time since I fought this problem). Now if I am following you correctly, if I have a 42 idle I should bump that up a step before going to the main. Only thing is the bike runs average and idles very well right now. It is when starting to pull a small grade or accel that it hangs up. That was why I was headed toward the main circuit.

Oh yeah more info for ya. It does have SE AC, and Vance Hines slipon exhaust. No crossover pipe. I didn't do this either that is how she came. Pics of her in the project section. Thanks Again

I am thinking s s here but if your pulling a hill and it is starting to give you problems say rolling in to the throttle at about 2000 to 2500 rpms your intermidiate jet if sluggish the jet is to large if it spits or strves then it is to small, checking the main is done at around 65 70 mph 3500 rpms roughly and if you have it breathing better then you will need to account for that so needless to say my opinion rests at the intermidiate range jetting

Did you take the petcock out of the tank and make sure it doesn't have any crap around it slowing down the fuel flow and starving it a bit ?

2nd point 1st & then I'm going to jump on the carb jetting deal with both feet. H-D didn't eliminate the crossover pipe on Sportsters as of '04, they just moved it so you don't see it running across under the carb. Aftermarket slip-ons that I'm aware of retained the crossover too - look up under the bike & see if there isn't a small pipe from front muff to rear, which is also part of the mounting.

Now then, as much as I love "old school", people (especially H-D dealers) set carbs based on settings from 20 years ago, treating the symptom(s), not the problem(s). If you were to see dyno charts with the air/fuel mixture graphed (not all dynos have the equip.), you'd see a spike in the A/F ratio where the carb goes way lean - that's where the "carb farts" come from.

The old way to deal with that was to go up on the slow jet (typically 42 to 45) & that turns the spike into a bump. The "seat of the pants dyno" says the problem is fixed but it's not & now the engine is running too rich in the lower rpm range. Adjust the idle mixture screw while the engine's running & get basically no change - that usually says the slow jet is too big.

The needle is the controlling factor & as it raises with more throttle, there's a transition as the main jet comes into the equation. That transition is the problem & putting in a bigger slow jet just masks it.

Many years ago somebody came up with the idea of using the needle from a 1998 XL1200 (N65C it's called) as a replacement for the stock one & if you look carefully, the taper is different. It's a bit longer too, but the point is it makes the transition sooner & faster. And more smoothly - look @ dyno charts - you'll never get a flat line on the A/F ratio, but the spike is gone & even the bump is gone - whole different ballgame.

Some use the NOKK needle for earlier models with good results, but the '04-'06 Sportsters seem to run fine with the stock (different) needle, sometimes with a shim. Unless there have been serious changes made to the engine (head work, cams, etc.), throw that old "you need a bigger slow jet" BS out the window. That's just a "Band-Aid" for the symptom while ignoring the problem.

Once you have the lower rpm range dialed in, you can see what the main jet needs to be - typically one size up from what the bike came with from the factory. Now here's something most H-D dealers don't know - you can get 1/2 size main jets too - for example, when tweaking an 883, if a 165 is a bit lean but a 170 is a bit rich - get a 167.5 & split the difference.

If you do have to go up from a 42 slow - and I'd bet you don't, you don't have to jump straight to a 45 as there is also a 43 & a 44 made. But the guy @ the dealership may look @ you like you came from Mars ;-)}

However, several HondaYamaKawaZuki bikes use the same basic CV carb we do & often you can find carb parts @ one of those dealers easier & for less $$$. H-D didn't make the carb - they bought it & just because you see "Genuine H-D" on something doesn't mean H-D made it.

Or that only H-D dealer can work on it -- most are 20 years behind when it comes to setting a carb up right.

- Art

Dang it Art why couldn't you have joined last August . This is some fantastic information and could have saved me a lot of trial and more error.

Ok, fill in information for you guys. The crossover on the exhaust is GONE. Exhaust has been off from jugs out. No crossover at all.

The carb has been apart a million times (thought of using velcro to put it together last time). I have cleaned it as well as I can. Have washed down every little piece and used my airbrush to shoot acetone through all the ports until it flowed clear. I would have to say it is completely clean. All new internals (gaskets, seals and all). This carb is as close to factory clean as any used carb could ever get.

I appreciate everyone's help and input. Sooner or later we will get this little piglet running like she should. Thanks again.

It starts and idles fine. Without load (in N) it takes gas fine, but during riding conditions it likes to cough and spit a bit. Actually had folks tell me "That's a sporty for ya" I don't buy that BS at all. I know it has to be better than that from factory and if HD can make it better then so can I LOL.

Go back to the baseline. The crossover in the exhaust being removed isn't good, but there's so little "overlap" in the stock cams, it's not a big deal. Start with a 42 slow, 165 main, 2.5 turns out on the idle mixture screw, the stock needle & no shim(s).

That should put you pretty darn close. Get the engine warmed up & go for a ride. If you get the "carb farts" & you know for a fact there's no intake leak, try adjusting the mixture screw while the engine's running & see how far you have to go for the engine to settle into the "sweet spot" - shouldn't be more than about 1/4 turn either way.

If that doesn't smooth things out, get a couple 10-cent brass washers from the hardware store & start with one on the needle - raising it up .010". Some folks have found they needed 2, but that's rare & only adjust one thing @ a time, or you won't know what did what. As mentioned, the "carb farts" come from the transition the needle controls & throwing bigger jets in just masks the real problem.

Scroll down a bit on this page:
CV Carburetor Modifications
to see a pretty good diagram of a CV carb & which circuit does what.

And if you're still having fits getting the rascal to work right, see if you have a local shop with a dyno - which has the air/fuel ratio "sniffer" attachment & a qualified operator. The dyno charts won't tell you everything you need to know, but they'll sure point out where the problem is & as mentioned, you'll probably see a spike in the A/F ratio somewhere in the 2500 rpm range.

Also, while most dyno tests are done by whacking the throttle wide open around 2000 rpm & holding it open to redline then snapping it shut, you don't have to do that & it doesn't tell you what's going on while you're running down the road @ part throttle. But the operator can run the bike thru the gears & hold a steady rpm as you do when actually out riding.

The A/F chart will tell you more than anything else - spike lean @ 2500 rpm, dip rich @ 4000 rpm & so on - I've seen it 100 times. As mentioned, you'll not get a flat line from idle to redline, but you can get pretty darn close & the needle has more to do with it than any other individual part.

- Art

If it starts and idles good, not vacume leak at intake seals. Wont idle for squat if leaking at intake seals. My 97 FLHT was always cold start, fart back then once warmed up run like scalded chicken. Has slip on straight pipes with baffels in place. I wound up drilling out idle screw port and re calibrating carb. Kit came with good directions and selection of jets and needles as well as needle shims. Patience and lots of plug reading, riding bike. Stock cam, will run up to 6000 now pulling good. Still had the need to be warm to take a lot of throttle but idled better cold. My stock ignition sensor just died. Not bad, 11 years. Changing to single fire, hotter coil, better intake breather, mild Andrews cam. Hotter plugs, good wires. We shall see. The re cal helped cold start, bumped up one size on idle jet, changed needle shape and tapers sooner, mid range much better and throttle response. One size up on main jet. It took much tinkering and walking away. It could be better, but untill other changes finished, Ill stick to where I was before Ignition died. LOL ( :roflmao: I blew carb off intake one time and singed hair on my face, freaked my wife out, had apart so many times, tired late, cranked one time to many without mount plate on carb and was gaging throttle trying to start sitting on my rolling seat eye level, Ka Boom, Cables only thing that saved my teeth. Funny as hell.:roflmao: ) I suspect I had weak spark for some time. Just a hunch but the having to be hot to run good in Florida is just not correct, that was stock from dealer. Dealer never helped. Oh we cant change factory(pollution idle) setting on carb. I also suspect spark curve now also. Wifes 1998 Dyna Low Rider Bone stock ran like sewing machine from day one, still does. Hum. WD 40 does work good to check vacume leaks as several others stated with red tube on spray. Burnt my intake seals idling in Daytona one year in traffic. 1 pinch past idle and it would smooth right out. Tried the WD trick suggested, sure nuff. Anybody played with the Accel programable Module. Im all ears.
Thanks JP