Carb problems

Hello all I just purchased my first Harley a few weeks ago. its a 05 sportster 1200C

I seem to be having some trouble with coughing and outright backfiring through the carb during off idle accel

I adjusted the idle mixture screw out 1/2 then a full turn.

Then re-jetted from 45 to 48 due to the advice of the group,multiple post on the net and the dealer recommendation having a lean condition


She still coughs
and now the plugs are black its embarassing and now completely stalls sometimes.

The idle screw doesn't seem to have much effect on the idle even when fully closed no stumbling.

I have heard its carb related or a symptoms of the dual firing ignition of the evo.

it has stock mufflers with the baffels punched out.. I was told it had a SE air cleaner and appears to have SE air cleaner but upon inspection all parts have Harley part numbers.

1. Could somebody tell me if SE cleaners have HD part no.
2. What could be the problem?
-- do I need to pull the carb and blow air through the idle circuit
-- close the main butterfly to allow more idle sensitivity
-- up the idle to prevent backfire and put the 45 back in.

zwhitr

Baseline is to (gently) run the screw all the way in & back out 2.5 turns. Shouldn't have to go more than 1/4 turn either way from there to hit the ideal spot. Only adjust when the engine's fully warmed up.

The 45 was to big to start with - you should be using the 42 the bike came with & I have never seen a Sportster engine that needed more, except for ones extensively modified with professional head work, larger valves, aftermarket cams, etc. Going up on the slow jet is a Band-Aid for the "carb farts" that's over 20 years old & treats the symptom rather than the problem.

That's because the slow jet is way too big.

Your ignition is single-fire - H-D changed the Sportsters from dual to single back in 2000.

Can't say for sure about the part numbers as the SE air-cleaner setup is different as of '04 & mine are for older models, but what I do know is that the 1st '04-up models had a paper filter that got holes in it quick (nobody has figured out why) & it's been replaced with a K&N reusable filter. And the backing plate is completely different from stock - it's just a flat piece of aluminum as opposed to a molded plastic piece that the "ham can" seals up to.

Sportster carb tuning is not rocket science, but you've got gimmicks on the market like the DynoJet, Yost Power Tube & Thunderslide kits. Only place you'll find those in a good tuner's shop is in the trash can. If you've got any of that stuff, toss it & go back with stock parts. The cause of the "carb farts" on Sportsters thru 2003 was almost always the needle, but the one that comes in '04-'06 models seems to work fine.

"kenfuzed" has a carb kit that looks good & I'll get around to playing with one of these days, but for a basically stock '05 Sportster, go back to the 42 slow, set your idle mixture @ 2.5 turns out & fine-tune from there, then see what main the engine likes. Prior to '04, a 175 main was baseline for a 1200, but the newer models came with larger mains & for some reason, not consistent. The '04-up 1200's have the XB heads which flow better than any previous version & also have the W grind cams which previously came in only the 1200S "Sport" model, so you'll probably need a 180 & maybe a 185. But jets are cheap & easy to change.

Riding down the road you're on the needle most of the time & you're not all the way on the main until full throttle @ higher rpms, so you want to get the idle, off-idle & lower rpm range tuned right 1st. Then let the engine tell you which main it wants.

:rant:
Dang, and here I was thinking that the Yost was good stuff only having used a ton or two of them. Always thought I was a pretty good tuner to boot..... guess I was wrong and now I know what a "good" tuner does with these "gimmick" parts..

Bob Yost has designed, tested and modified CV carbs for years. He has more knowledge of the CV than most "tuners" could ever learn. I worked with Yost products from about 1995 until I closed shop in 2005 and although he copied some of my products I still would use the power tube in a second. I would enjoy listening to you and Bob having a conversation about his parts being a gimmick and junk. I corrected many lean pop problems with a simple idle mix adjustment or jumping to a larger pilot when needed and still stayed within the idle emissions test in AZ. As for DJ, the Thunderslide kit was a miss but they have some good kits out there. Yes, a good tuner can make runs on a dyno or do plug chops (man I did a lot of those before I got the dyno) and with the ability to read plugs and know what the engine should be doing get the jetting spot on. But the average DIY? it will be a long, frustrating weekend.

In the nearly thirteen years of running DP the knowledgeable vs. the rookie do it yourselfers was about 500:1 or better. That was, is and will be the purpose of tuning kits and even the PC's and Techlusions and other products that allow EFI to be tweaked by hand. I know many tool and die makers, craftsman, pilots, engineers, architects etc, etc, etc that are outstanding in their fields but might as well go stand in a field when it comes to reading a plug or doing plug chops but they have the desire to learn and do things themselves. To lump all of these kits and devices into a class of "gimmicks" is doing a dis-service to those that are honest and have developed good products and provide great support for customers. Are there junk kits out there? Sure, CCI had the Rev-Tech clone of the DJ kits and they were a walking turd fest.

Art, those comments were very uncharacteristic of you and I believe they were biased and unfounded. Your information and posts are without exception informative and spot on and always balanced. So I was surprised at this comment.
:cheers:
BTW, I did speak to Bob about the copying my CCP products and he explained he thought I was gone entirely. So, I have no issues with him at all as he always shot square with me.

I apologize for that CD, but I have to say what I've experienced & FWIW, my background is in automotive technology & mechanical engineering. I always wanted a Sportster & hadn't had a Harley in years since the 1947 Knucklehead that was my 1st bike, riding mostly Yamahas in the interim. After I got the '95 Sportster I saw the carb kits & was lucky to find 2 great independent shops owned by guys with 40 years H-D experience & learned from them. This works, that doesn't & here's why. One shop I go to for things I don't have the equipment to do myself has a little website: ECS ENGINEERING Although Pro Nitro Harley drag bike parts come from there, you'll see a lot of stock or close to stock bikes in the shop too & the only place you'll find gimmick carb kits is in the trash can.

Then I joined the Sportster List Race Team, putting together a 167 HP Sportster-based engine for Land-Speed-Record runs & working with guys running the Production classes. All team bikes set records @ Bonneville & we won the 2002 ECTA Championship too. I've got a substantially modifed S&S "Super D" carb on my race engine, but run stock CV carbs on the street bikes with the infamous N65C needle & jetted for the application. The bikes in the Production classes ran stock carbs, as required by the rules. You can change the needle & jets, but you won't find any of the gimmick carb kits on those bikes, including the "Hugger" Sportster that ran 146.976 mph @ Bonneville.

On the way out, we dyno-tuned @ Nallin Racing Head Service in Colorado & those guys run primarily Buells, but they do know Sportsters & Big Twins too. You will not find any of the carb kits out there either. They like Mikuni carbs for the classes that allow them, but with stock parts, will get a CV to work great. One of these days I'll get the kit "kenfuzed" has to play with, but my little 883 "girl's bike" will pull the front tire shifting into 2nd gear & will dust BT's. 883>1200 makes 95 HP @ the rear wheel with a stock CV carb - N65C needle & different main jet from stock, but no aftermarket parts. Simply put, if the DynoJet, Yost or Thunderslide kits actually worked, we'd use them - but they don't & both the dyno & the time-slips from the track say so.

Yes, you can say the track & the street are 2 different things & they are, but @ Maxton, North Carolina, you start from a dead stop & have 1 mile to run on a concrete runway where WWII glider pilots were trained. The Army Golden Knights parachute team sometimes uses that track too. Then you've got 9/10ths of a mile to slow down before you run off into a field. Unlike a drag race, it doesn't matter how long it takes you to get to the finish line, it just matters how fast you're going when you get there. But obviously the better start you get, the faster you'll be going @ the finish line & such things as the "carb farts" are intolerable. Every trick in the book has been tried there & you will not find DynoJet, Yost or Thunderslide kits on the winning bikes.

Track record for a "naked" Sportster is 180.025 mph (my engine) & overall, a tick over 250 mph on a turbocharged Suzuki Hyabusa. There is the slight possiblity that we've learned a thing or 2

art jr is the man for sportster carbs and pipes, has got all the stuff dialed in, thanks for your tech support and knowledge, learned alot from ya about my sporty thanks to you, just thought I'd throw one out to ya, since no one else does.

What about checkin your enricher(choke cable) if its not seated right you will run a severe rich condition, and can cause stalling at idle and performance will suck up or 3/4 throttle, and still not perform as good as it can.

I don't know about all that carb stuff, since mine has always run well except at high alititude (until I got it adjusted when I moved to CO).

Anyway, Screaming Eagle is an H-D brand, so I wouldn't expect anything other than an H-D part number.

I don't think the 45 is too big just look at plugs with the 45's in.


I attached a few pics of my plugs both after i jetted to the 48 and then again after i reverted back to the original 45

What does that mean?

Does mine being an 05 fire both plugs alternately or both at the same time reguardless of the compression stroke every time the piston is TDC

I did not see any numbers on the needle but I attached some picture for your review


Alright I don't want to cause a big feud.

Then what seems to be the problem I have an 05?

How do these compare to SE or cycle shack.

eBay Motors: NEW SLASH DOWN SLIP-ON MUFFLERS 04-08 HARLEY SPORTSTER (item 370070145496 end time Jul-25-08 07:51:37 PDT)

Single fire ignition fires the the plug in the cylinder that is on its compression stroke.
The plugs on the left are still too rich and the "needle" pic looks like the enricher valve,(sry,idle adj screw, too many Canadian pops last night) not the needle jet. The needle jet is in the vacuum piston and raises and lowers with it. You can see it it the mouth of the carb.
I would set it up the way Art suggests since he and CD are way into the upper level in knowledge an experience.
kenfuzed also has carb kits that I hear are very good and would work well for you.

Way too rich on both & your bike came from the factory with a 42 slow jet. With the additives in today's gasolines, the ceramic insulator on the plugs should be white or no more than a light tan in color & if you see a black ring around the end of the threaded section, you’re running too rich. The main appears to be a 180 & that should be the baseline for your bike, although you may want to try a 175 & a 185 – I would, but only after getting the low end dialed in.

Yours only fires the plugs near the end of the compression stroke & there is no "wasted spark" on the exhaust stroke as with the older "dual-fire" ignitions. The firing order on a Harley is 315-405 in terms of flywheel rotation so we're dealing with an "odd-fire" engine & that's why Harleys sound like they do.

The needle I was referring to is the one that goes down thru the center of the carb & you have to take the top cover off to get to. Raise the slide up with your finger & you'll see the taper on that needle, which regulates how much fuel can come out of the main jet. But as mentioned, the stock needle that comes on '04-'06 Sportsters seems to work fine so you should not need to mess with that. On earlier models, the "carb farts" came from the fact that the stock needle wasn't shaped right & the transition phase didn't work right. You can see it on dyno charts where a "sniffer" was used in the exhaust & the air/fuel ratio is graphed - the A/F ratio spikes way lean for a moment, usually in the 2500 rpm range.

1st thing is you're way too rich on the low end. Get a 42 slow jet & set the idle mixture screw @ 2.5 turns out. Don't mess with the needle or the main jet until you get the idle, off-idle & low rpm range working right, which should not be difficult. Just get the engine warmed up & tweak the idle mixture & idle speed screws. And if you don't have the factory service manual for your bike, go get one - it has good diagrams as to how the carb works & is very helpful for any service work you do - far better than Clymer, etc. manuals. But here's one diagram you can refer to as well - scroll down a little bit:
CV Carburetor Modifications

Art, then we disagree. You have your experiences, I have mine and I installed, many, many power tubes, tweaked and tuned a few hot rod HD on my own dyno a "few" times. I never said that the kits were the end all or be all. I said and still say that the kits were aimed at the majority of do it yourself types that have little or no tuning skills but want to learn. I went the light spring, 1/8" hole and the right jets a bunch also. Spent a few years going fast 1/4 mile at a time and built one hell of a very light weight 110 hp / 103 ft lb FXR that would put you on your ass in a heartbeat. Got sick before I really got to wring it out but it was wicked quick. It handled like a wicked fast FXR and was really fun in the twisties.

The point being is that in your opinion thay are gimmicks and in my experience in both working with DJ and Yost on products and selling a lot of these kits is that they work and are not by any means gimmicks.

Now, I ain't got a degree in engineering but if you wanna go fast over a runway try doing 500kts at 500' and go vertical to 25k and do an immelman and hang in the harness looking down at Tampa. Then try pulling 7.5 G's playing with other F16's over the gulf of Mexico. Now that will put some hair in the right places.

I think that if you checked it out you'd find that more than a few on this board have gone fast both on the ground and in the air. Speed is fun and it don't matter if it is straight, curved or in the air.

Now, I am gonna go fishin' I forgot I don't need to worry 'bout running this board anymore. :witsend: :roflmao:

Yup!
I learned a thing or two and I don't even have a carb.
I sometimes wish I did cause it may be easier that dicking around with this PC.

I just love Carbs, so much to talk about, so many different ways to get them to work.
But it is all a fine line. The site Art recommended is a great site, I have used there advise lots of times. I Don't care for Thunderslides they are to light and the needle is not quite right, I have one laying around some place, I just can't through any thing away. I have never had a yost tube so can't say about it. I am not taking sides but i'd stay with the HD parts when possible.
A shop manual is a must for any owner and read from front to back.
For the last four years or so I have been using a couple of the carbs that Ken modified. Of course I have had to tweak them a little, One is on a 90 Evo and the other is on an 05 TC neither are completely stock. Both get 50 plus mile per gallon. We live in Colorado at 6,000 ft and usually only go up in altitude from here, except for when we go on vacation or to Sturgis, only if we go to sea level do I ever change the main jet. I generally listen to what Ken has to say and adjust from there.
Just my 2 cents worth
Old School
DW

Your standard carb operates on four circuits. Idle, off idle or about 1/4 throttle, midrange 1/4 to 1/2 throttle, and highrange, 3/4 to full throttle. Other than accelleration, most of your riding is at about the 1/4 throttle position. Full throttle is where you obtain your max horsepower.

When tuning your carb start with the low end circuit, idle and the 1/4 throttle position. General rule of thumb with the A/F mixture screw is, less than 1 1/2 tuns out, the pilot jet is to large. More than 2 1/2 turns out, pilot jet is to small. Remember, the pilot jet is feeding fuel during all four phase of the carbs operation.

Next go to the full throttle position, if necessary, make your adjustments here with the main jet, don't want to loose any of that horsepower. Now go to the midrange and make your adjustments with the main jet needle. If you set the midrange by changing the main jet, you will sacrifice performance at full throttle. And of course this is all JMHO

I took the 48 back and got a 42 it seems to have plenty power just doesn't idle as well too low.. before i would pull the enrichner to start and then push back in now it starts to stumble when out and when I push back in it begins to lope

I cleaned it prior to picture

I am not sure why you think its not harley it has the little symbol stamped on it. I have a N4NN needle I checked everything I saw no clips or slots.

Do you have a picture of the DJ kit to know what is am looking at.


Do any of you recommend doing the slide modification step 3

CV Carburetor Modifications



Thanks all for your help.

looking in to exhaust system cycle shack or SE II (300 bucks ouch) has any body seen the cycle shack knock offs on ebay


eBay Motors: NEW SLASH DOWN SLIP-ON MUFFLERS 04-08 HARLEY SPORTSTER (item 370070145496 end time Jul-25-08 04:24:03 PDT)

Just set your idle mixture screw @ 2.5 turns out for a baseline & raise the idle speed as necessary. Once the engine's fully warmed up, you shouldn't need to adjust more than 1/4 either way in the mixture screw until you hit the "sweet spot". And the idle speed will rise as the engine warms up, so adjustments made before the engine is completely warmed up will be off.

I sure don't.

I don't pay any attention to e-Bay & buy nothing online (don't use credit cards) but you can surely find SE, Cycle Shack, KromeWerks slip-ons for a lot less than $300. Do you have an indy shop nearby? Or a catalog like J&P Cycles, Dennis Kirk, V-Twin (free for the asking)??