Just wanted to pick that tuner's brain of yours. On my 1200R, I have installed the SE A/C, Khrome Werks slip-ons and initially went to a 44 pilot and the '88 needle.
Also installed the EZ-Just mixture screw. Couldn't tell much in the way of difference in idle when trying to adjust the mixture. Assuming the pilot was too rich, I went back down to the 42. That opened up the mixture adjustment some, but not what I am used to on other bikes. Bike seemed real rich at transition-if it were a 2 stroke, I'd say it was 4-stroking. Main jet is stock 180. I am at sea level. I replaced the EZ-Just with the stock idle screw...I decided to look at the spring, washer and 0-ring, which I hadn't before. They came out: spring, 0-ring, then washer-backwards on the last two. Don't know if I could have flipped them when installing the EZ-Just or not. I set them in correct order on the stock screw. Mixture seemed more easy to adjust. Blipping the throttle yields clouds of smoke...too rich. The bike actually runs very well down the road, but mileage is atrocious...30-35 mpg! I have not messed with the float at all (nor did I check it). I thought the enrichener might be stuck on, but there is some slack in the cable when it is closed-I checked the metal ferule and the cable is seated correctly in it-but I didn't actually remove the enrichener from the carb body. Going down the road, crusing at about 70 mph, I am right at the transition area in the carb...the throttle is barely cracked. The bike accelerates crisply...it just doesn't like the transition area at all...just kinda 'blubbers' there...again, sounds too rich to me. Gonna go back to square one and put the stock needle back in, hoping that it makes a difference and clears up the transition without giving me back my carb farts.
I have a hard time visualizing that something in that narrow a range, involving primarily the pilot circuit, can so drastically affect mileage without some gross fuel-dumping going on.
Hoping you can share some wisdom and help me from having to re-invent the wheel!

Thanks!
Kim

I had the "blubber" problem at the low speed transition with a 45. I put in a 48 and it went away. A 46 also keeps the bluuber away but then I run lean, white tip plugs. Don't know if this helps but that was my expeience.


By the way Stevo, that avatar gives bad thoughts :p . I want one but for some odd reason I don't think the wife would approve. :frownthre

Well, I'm not Stevo ... IMO, if you use the thinner 88 needle, or any other aftermarket thin needle, you need to dump that 180 main jet and install a 170.

Why ... Stock, the 04-05 bikes run too lean at idle and partial throttle acceleration ... but too rich a wide open throttle (WOT). Steady cruise air/fuel mixture is about the only thing that is right from the factory.

1. You fixed the lean condition at idle with the 45 pilot jet. Set the idle mixture screw to 2 1/2 turns.

2. You fixed the part throttle lean condition (during normal acceleration) with a thinner needle.

3. You are too rich at WOT due to the big 180 main jet. Install a 170 and you will run much better and gain HP at WOT. The 170 jet will also lean out the cruise fuel/air mixture (non-accelerating) and get your mileage back.

Drill the slide hole: On the bottom of the slide are two holes. The center hole is for the jet needle. Don't mess with it. The second hole is off-center. This is the vacuum port. This hole needs to be drilled out just slightly to 1/8".

Leave the stock slide spring in the carb.

Make sure there are no vacuum leaks, and make sure the slide spring diaphram is fully seated in the groove prior to installing the car's top cover.

Note: After the carb is all put back together ... with your finger, move the slide fully up. Make sure it falls back down freely. Just make sure the slide/needle assy. are not jammed.

Just my opinion, but a change in pilot jets [will not] effect your overall fuel mileage to the extent you have. The pilot jet alone is not causing your very poor mileage problem.

Steve may be of more help ... But I think if you make these changes on your 1200 Stage 1, you will be right in the ballpark.

Enjoy, :)
Ron

BTW, I would love to have my bike painted yellow pearl. May just get it repainted one of these days. I fell in love with at color when a friend of mine bought a brand new 98 1200 "Sport". It was all yellow and black (even the pipes were black). Bike looked like a bumble bee going down the road ... It was very very nice. Just looked FAST!

Oh ya ...

Once it is running good, making good power, and getting normal fuel mileage, put the bike on the rollers (dyno) and you can confirm correct fuel/air ratios and make slight changes if nessesary by shimming the needle.

DO NOT DRILL THE HOLE OUT TO 1/8"


I'll explain later when I get up...(just got back from a concert and it's 3.21 AM and I'm drunk) and go thru the rest

Okay, just came back in after tinkerin' and taking a short (3 mile) ride. Took the carb down. With the slide out, I was able to see and check the enrichener valve...it is fine. I checked the float height...it, too is fine. I swapped the 42 pilot for a 45 and changed back to the stock needle. I had already gone back to the stock mixture screw. Two turns out. I checked the float bowl drain screw, just to be sure I hadn't Homer'd it (hell, the fuel had to be goin' SOMEWHERE!). Fortunately, it was fine and not leaking. No holes in the diaphragm. Accelerator pump is okay. Cranked it up and set up about a 1400 rpm idle with the throttle friction control. Pushed the enrichener in to half immediately and all the way in after 30 seconds. Waited until the rear rocker was warm and then released the throttle screw. Idled about 900. Took great hunks (okay maybe yankin' it to half open) of throttle without any hesitation...and without any black smoke. This is an improvement. Going down the road at about 25 mph...yanking the throttle produced an immediate response. Didn't do any high speed stuff yet as it started to rain. Mayhaps tomorrow will bring some sunshine and I can do a 'loop' or two then get back to all. Ron, I may think about the 170 main, especially if I go back to the 88 needle. I have a sneaking suspicion that the 88 needle is just rich enough off idle to have caused my problems. My areas of difficulties were far enough down throttle that I don't think the main jet was actually involved. I was, literally, just cruising with a EG Classic at about 70 mph. But my throttle position at that speed in 5th was just 'off idle' and I was turning 3250 rpm. The bike had run great to my seat-of-the pants yesterday with the only glitch being in the transition from the pilot to the needle-where I found myself...a LOT.
Thanks, Ron, Barry and Stevo (hope the head's not hurtin' too much :D )

BTW, Ron...I will try to post some pics of my scoot. The Yellow Pearl, to me, is a very complimentary color for the bike. But please...PLEASE...if you want a yellow pearl bike-don't paint over your excellent silver paint job!!! Buy a set of tin on ebay...puhleeze!!


Kim

I'm interested to hear why Stevo doesn't like to drill the slide. I do mine and have no complaints.

OK ...the heads not hurting BUT it's not real clear yet either and I'm goin stuntin in an hour or 2 and I've gotta do a set of 883 heads this arvo.


What needle does it have stock???? ie: what are the letters on it..

The 88 sporty needle says N65C

Theres not much difference between the N65C and some of the later series that are in the twin cams.
To give an example an N8EA has the same straight portion diameter and just past the straight and only differs about a thou at most of the points from there.
The N86 series and NOK series are 0.108" dia where the N8EA and N65C are 0.107" on the straight portion

I'm not familiar with the EZ pilot screw so I can't offer anything there.

Part of your problem is that you did a few things all directed at one area..this stacks up and gives too much.


Most of what Ron said I agree with.
There ia a relationship between the needle and the main jet and different needle will often require a different main BUT I test not just change for the sake of it.
Hold the bike at a constant speed in 4th or 5th at about 5500 rpm then roll off the throttle just a touch.
If it accelerates it's often a sign of too lean.
It should just slow slightly.

the best way to test is down a drag strip and use the trap speed.

A slightly rich main is not really a problem and it's better than a lean one.
You also have to take into account what the air is like and add or subtract a correction factor.


I've found that on 95% + of HD's all that is need is to go up one or 2 sizes on the pilot and sometimes a needle raise of up to 0.050".
Rarely do I need to change mains if the stock needle that came on that bike is still in there.

To give an idea my 98 1200S has

stock main
stock spring
slide drilled a couple of number sizes up and modded
stock needle raised about 0.025"
48 pilot
pilot screw about 1 1/2 - 2 turns

This combo ran 11's consistently and has been on many other bikes for testing a base line...It's currently on a Suzuki Intruder that I'm fitting a HD cv to.....although there is heaps that needs to change on it :frownone




Hey Crim I have my slide drilled out too BUT not to 1/8".... I've found this to be too much on most mildly modified bikes.

I go up a couple of number drill sizes from standard on modded bikes but it's still usually a few sizes under 1/8"

If the slide is drilled too much then it raises too quickly under acceleration.
This can be beneficial if the motor can spin up quick enough and the acc pump is a bit small for the motor in question BUT on most mildly modded motors it will be too much and cause the bike to bog

Once the rest of the tuning is spot on then you can sneak up on the slide hole by trying a number drill size or 2 at a time but be careful as ya can't put the material back in and slides aren't cheap.

Vacuum hole size is really the last thing ya should be tuning.....when everything else is right THEN have a go.

And it's beter off being a touch small than too big




OK that's enough for now...now I HAVE got a headache :shhhh

Stevo, the 88 needle is in fact the N65C. The stock needle is, I believe, N4NN. Right now I have the N4NN needle and 45 pilot. The bike was going seriously rich right off idle with a 42 pilot and the N65C needle. Mixture screw didn't seem to help out very much (?) with the latter setup. Will try to throw a leg over tomorrow.

Thanks again all!

Kim

G'day Kim
I havn't had any 04's in yet

and I havn't seen any N4 series needles yet...so I don't know their size or shape.

Do you have a pair of vernier calipers????

Stevo .. I just recommended drilling the vacuum port in the slide because I told him to use a stock slide spring. Most of the carb kits out there (ie: DynoJet) have you not only drill the hole in the slide, but also use there lighter spring ... That combo does make the slide open too fast for a street bike in most cases. It will give stumbling and carb farts under normal driving.

In my case, I have found that drilling the slide, but using the stock spring quickens up the slide a little, but not excessively. I guess you could do about the same thing by [not] drilling the slide and just using a lighter spring (if ya had one).

That's all I was recommending.

Under WOT, that needle is completely out of the main jet (it's then out of the picture) ... I still don't think he needs anything bigger than a 170 main.

In my opinion, Kim is also too rich at partial throttle when he uses that thin needle [and] the 180 jet. That's why he states it runs better with the stock thicker needle and his 180 jet.

I don't have the experience that folks like Shu, Crim and Stevo have in regards to Harleys, but I am still convinced that the thinner 88 needle and the smaller 170 jet combo will give him good results ... lightly richer in the partial throttle acceleration than the stock setup, a slightly leaner & cleaner constant cruise, and not Pig Rich at WOT like the stock setup (his carb came stock with a 180 jet)

Hey ... Ya got to experiment, but you still need a good start point.

Ron,

ahhh springs

By changing the stock spring to a lighter one the slide will actually sit higher for all throttle openings, so it will be richer at all constant throttle positions as well as rise quicker.

Changing the vacuum hole only changes the RATE of opening ...NOT costant throttle slide position.

I have my CV on a suzuki at the moment on a manifold I made up for the job....it appears on initial testing (it's only been on a couple of days) that there is more manifold vacuum than on the HD's and I will need a stronger spring to compensate.

A cv carb is good carb design that is put together by engineers with a LOT more experiance than what we have....the trick is to work out what consraints that the engineers had to work with ie: EPA requirements.
Often all that is required is to just remove these restrictions.

I'm finding the same thing in late model EFI bikes too. They tend to be lean where they are required to pass EPA tests and rich up the top.

also fuel/air ratio requirements are different for differing conditions.

for example a good all round carb/injection system would have differing air/fuel ratios for differing parts of the circuit

1/2 - WOT 12.5:1 - max power - acceleration
1/4 - 1/2 13.5:1 - piston and valve saver in the twisties
1/8 - 1/4 14.5:1 - perfect for highways, good fuel economy
Idle- 1/8 12.0:1 - no spitting, coughing or stumbling at light throttle starts

By changing the stock spring to a lighter one the slide will actually sit higher for all throttle openings, so it will be richer at all constant throttle positions as well as rise quicker.

Changing the vacuum hole only changes the RATE of opening ...NOT costant throttle slide position.
Good info! ...

I can tell you ... My 04 Sporty [did not] like the light DynoJet spring at all. Went back to the stock spring / drilled slide combo, and everthing was right with the world again.

This was with a 170 main, 45 pilot and DynoJets needle on my 1200.

1/2 - WOT 12.5:1 - max power - acceleration
1/4 - 1/2 13.5:1 - piston and valve saver in the twisties
1/8 - 1/4 14.5:1 - perfect for highways, good fuel economy
Idle- 1/8 12.0:1 - no spitting, coughing or stumbling at light throttle starts

Exactly!

To see how much main jet changes affect air fuel ratios, please look at this dyno sheet on JT's website. In this two run comparison, the main jets are a 190 and 165! Dropping the main jet from 190 to 165 caused a 2 point leaner air fuel ratio. This will give you an idea of the effect of the main jet.

http://www.jtcentral.net/xl/XL_thunderheaders.htm

Tune your idle mixture first...before changing the jet of anything! If your idle mixture ends up being 1.5 to 3.5 turns out then you most likely have the correct slow jet. I prefer a slow jet that yields around a 2 to 2.5 out mixture setting.

Next, set your main jet. The way Stevo suggested is a good way, if you have a back road where you can do this safely. The lower the gear you are in the more difficult it is to feel what he described because the gear will be trying to slow you down. However, 5500 in fourth gear on most Sportster's is about 100 mph!! So, be careful if you chose to try this. If not, in many cases the stock main jet is typically plenty since it is not regulated by the EPA! So leave it alone for now (unless you are using a DynoJet kit which gives you a pretty good starting point, then follow their directions).

The midrange is where we spend most of our time (1/8 to 3/4 throttle). There are a lot of this that effect the midrange. Needle, slide weight, slide spring pressure, and many other variables in the slide design. If you are choosing to run the stock needle, then most likely you will need to shim it since this is regulated by the EPA! And therefore it is typically a little lean. In most cases a .02 to .05" shim is all that is needed. Start with a .025 washer and see how that feels, then add another waasher and see if that feels any better. Settle on the one that gives you a smooth feel when cruising and yet pulls strong through the midrange. Again, if you are using a kit, follow the directions.

After you think you have it set close, spend the money and have it put on the dyno. First have them let the bike idle and check your idle mixture air fuel ratio's. Next, have them do several 2000rpm to redline pulls. This will show you how the carb transitions. Then have the operator do some steady speed holds at say 2200, 3400, and 4000rpms. This will show you the air fuel ratios when the bike is cruising around at steady speeds. Once you have all that information, you can make whatever changes you need to get as close as possible to the ratio's that Stevo posted above.

It is possible, but can be tricky to really dial one in if you are not real good at being able to 'feel' what the engine is telling you. If you find yourself not being able to 'feel' what the engine wants, then save yourself the aggrevation and put it on the dyno like described above and make sure it is correct. It may be the best $30 to $100 you have spent.

I know this is dated pre'04 sportster's, but the concept is fine, just don't follow the quoted jet sizes.

http://www.sportster.org/tech/carb/rejetting.html

Linky no Worky



Does now..fixed it... :shhhh

G'day ....These numbers are just a guide....but they give a good starting point

1/2 - WOT 12.5:1 - max power - acceleration
1/4 - 1/2 13.5:1 - piston and valve saver in the twisties
1/8 - 1/4 14.5:1 - perfect for highways, good fuel economy
Idle- 1/8 12.0:1 - no spitting, coughing or stumbling at light throttle starts
__________________

G'day Kim
I havn't had any 04's in yet

and I havn't seen any N4 series needles yet...so I don't know their size or shape.

Do you have a pair of vernier calipers????
__________________



Sure do, as well as a set of mics. The N4NN needle is in the bike now and today I ride!(sunny and in the 70s). I will pull it out and take some measurements asap for any who would like to know(let me know at what lengths you'd like it measured). I do appreciate the measurements on the N65C...I could visually tell(although my peepers may have been playing tricks;) ) it was thinner in the parallel section. You were spot on, as was Ron regarding too many variables at once. I felt that I needed a richer setting down low and I am surprised that I allowed myself to get caught up in the "brand new bike...let's break out the wrenches" syndrome, lol! I didn't even crank it up after changing the mufflers and A/C :frownthre . Just tore into the carb and started changing stuff. Yeah, I KNOW better...but, see, I was EXCITED-finally another bike after my only real dry spell (15 yrs)! So excited that I forgot the golden rule of troubleshooting: Only change ONE thing at a time-and evaluate the effects of THAT change, first, before changing ANYTHING else...

Shu, thanks for your input, as well-good info. I have already read Maurice's article.

Kim

G'day Kim

WHen measuring needles. I put a known needle against the unknown one and use a vernier caliper to measure.
This gives me a plus or minus at a particular point, which is really all ya need at the end of the day.

Here's a chart if I can get it to work. You can add to it if you wish.



http://www.iqconnect.net.au/~stevo/CVNeedles.xls

Stevo-will add to it as soon as I take the needle out. I have apparently hit upon 'the' combination. Went for a loop today-beautiful weather! I was using the 45 pilot and the N4NN needle. Idle screw was out 2 1/4 turns. The transition from idle to just 'off-idle' was seamless. No more 'blubbering'. Any roll-on...from idle anywhere on up...was immediate with no hesitation or flat spot. The entire throttle range was linear. And, for immediate gratification, I turned just over 50 mpg (same loop that I had gotten 30 mpg before)!
Methinks Samantha is happy now!

Thanks to all for your insight!

Kim