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Discussion Starter · #1 ·
I'm trying to help a friend who's got a 2000 or 2001 Heritage Softail that complains how gutless it is power wise & gets pretty low gas mileage, probably in the low to mid 30's range. It's stock 88" with true dual pipes & SE air filter.
He's also getting carb backfires now since it's gotten cooler so I know it's running lean on the slow jet. I had the same issues when I first got my FXDL so I have an idea what we are going to be doing to fix his problem.

So he comes over, we pull off his a/c cover & it has raw gas pooled on the bottom edge. HMMM? Then we pull the A/C off, more raw gas. About a teaspoon or two. His mixture screw is out 1 3/4 turns. I pull the float bowl & I replaced his 45 slow jet w/ a 48.

I expect him to have a dealer installed Dynojet kit, but when I pulled the main jet & emulsion tube it doesn' look the same as I remember mine. The emulsion tube seems to look different & you need a special tool to get the 185 main jet out. I seem to remember the emulsion tube I had as being a hex that you could hold onto & use a screwdriver to remove the main jet. Check out the pic & help me figure out what I've got here.

I pulled the top cover & it has an adjustable needle w/ the c-clip on the 4th groove from the top. We moved it up to the 3rd groove to lean out the top end a little.

Put it all back together adjust the idle srew at 2 turns out & take it out for a spin. Definite improved power. All is looking good. Get back to house & out of curiosity pull the A/C cover to check for raw gas & sure enough. There is raw gas coming thru the hole the a/c cover screws into on the filter.

All that typing to get to this: Why isn't the gas getting sucked into the carb all the way & getting burnt & what can I do to fix it? Is this jet kit all Dynojet parts or a mismatch of Dynojet & stock or other mfr. carb. parts? Could his true dual pipes be a cause?

Also he has a puke tube w/ a filter on the end & a breather cross-over so nothing is being vented into the backing plate.

Sorry for the long post trying to give all the info up front.
 

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Get rid of the needle and the #48 jet, the #48 is to much with a stock motor especialy with i/m screw 2 turns out. I can't view the photo but a dealer could tell you if it's a sock imulsion tube. Check to see if the slide has been drilled to 1/8" this can somtimes create a lean condition with the slide shooting up to quick also check slide spring to oem. A good base setup to try would be a #45-(#46 aftermarket jet), stock needle w/ 2 shims, stock tube, slide, spring and a oem 190 main. Gas problem sounds like the needle may not be seating well or a sticky float. The sportster needle is another option but I would shim the stock needle first. IMO the Dynojet sucks in the tunning and mileage department, sounds like thats what you have at 30 mpg..
 

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I always ask what is your elevation where you live before I give jet reccomendations. I see your in AZ, however I am familiar with most states and I know that there is a huge difference between valley and up north in elevation, so where are you located? Most likely, ( but not defineately ) you have a dynojet tuner kit in the carb. Most people confuse it with the dynojet Thunderslide kit, not the same. The tuner kit doesn't include the slide etc. Anyway the tuner kit will come with the different emulsion tube and different jets that are smaller where they screw into the emulsion tube. So you can use it, or change the emulsion tube and the main jet back. However, I don't believe that is your problem. The first thing I would do is check your float level. If you don't know how to properly do this, get some help, though its not hard. If your float is set correctly, make sure your carb is venting properly. Also clean your air cleaner. Next I would check to see how your idle screw is set. Is your butterfly adjusted properly? Have you opened or closed it off to compensate for another problem? Keep in mind that too much gas washes the oil off the cylinder walls and helps wear piston rings. Which brings up the question of compression, valve sealing, and ignition timing which could be causing this also. But again, I think its carb and carb adjustment. Let us know.
 

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Jeff S. said:
I always ask what is your elevation where you live before I give jet reccomendations. I see your in AZ, however I am familiar with most states and I know that there is a huge difference between valley and up north in elevation, so where are you located? Most likely, ( but not defineately ) you have a dynojet tuner kit in the carb. Most people confuse it with the dynojet Thunderslide kit, not the same. The tuner kit doesn't include the slide etc. Anyway the tuner kit will come with the different emulsion tube and different jets that are smaller where they screw into the emulsion tube. So you can use it, or change the emulsion tube and the main jet back. However, I don't believe that is your problem. The first thing I would do is check your float level. If you don't know how to properly do this, get some help, though its not hard. If your float is set correctly, make sure your carb is venting properly. Also clean your air cleaner. Next I would check to see how your idle screw is set. Is your butterfly adjusted properly? Have you opened or closed it off to compensate for another problem? Keep in mind that too much gas washes the oil off the cylinder walls and helps wear piston rings. Which brings up the question of compression, valve sealing, and ignition timing which could be causing this also. But again, I think its carb and carb adjustment. Let us know.


What does the slide look like ,,,, my stock glide started this hickup thing in cold weather ,,,,, when we got into the carb ,, the ears on the slide were worn really bad causeing a lean condition.... new slide ,, problem fixed. The bike had 44k on it .......rat
 

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Az,
The emulsion tube and needle you have pictured look like Dynojet parts. You have to hold the emulsion tube with pliers to remove the main jet. The stock tube has flats for a wrench.
 

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Discussion Starter · #6 · (Edited)
Thanks for the replies. Jeff I'm in Phoenix (a valley) & you're right about the tuner's kit as opposed to the Thunderslide kit. I'm sure this tuner's kit was installed at the dealership the bike was bought from. With the 185 main & 48 slow I think my jettings are good. Before I went to a 95" w/ 44cv carb on my own bike these were the same mods I had to make to my 40cv carb w/ the 88" & it ran real good.

My main concern with my friend's bike is the accumulation of raw gas not being sucked thru the carb & into the engine & the cause of it. I wanted to try & verify the parts in the carb were truly from dynojet's kit since from memory the emulsion tube looked different. I've never seen a stock 40 CV needle & emulsion tube. The Dynojet kit is a good kit IF it is set-up right which when it is installed at a dealership the generic set-up is always used. BTW the slide was not drilled.

One thing I didn't mention previously was when we pulled off the breather crossover it had a lot of thick oily, gritty gunk in it. I don't know where the gritty stuff came from. Also the filter on the end of the puke tube was full of oil. I'm wondering if the heads are not breathing properly & if that could be why gas is not being pulled thru the carb properly.

This bike was bought used from a dealership & has 27k miles on it. I suspect it may have been sitting awhile before it came into the dealerships hands.
 

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Az,
Try turning your i/m all the way in and 2-3 turns out and see if you get much of an rpm change if not much change try the 45 or 46 pilot. If your deadset on a 48 in a stock motor with i/m 2 turns out be prepared for carbon build up in your motor and sooty pipes and plugs. The majority of all riding is done in the needle circuit which is why I would suggest shimming the stock needle two shims or the sportster needle with the smaller pilots. I have yet to see a well tuned dynojet kit that got acceptable mileage or an increase in power worth the tradeoff. The dynojet being good if set up right is a big IF at best. The techs I know and myself like to toss them in the dumpster. There are alot of good tuners in Phoenix I would make a few calls about your friends jetting and see what they suggest for a simple 88" stage one. Harley tech talk would also be a good place to post your jet and gas questions.
 

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Lets concentrate on the gas around the filter and in the carb. We know that the difference in pressure from the piston decending is drawn through the venturi of the carb and pulls the gas in. So its either being pulled in and not allowed to pass the throttle plate, being pulled in and the reversion in the intake manifold is pushing it back at low speeds and shut down because of incorrect throttle plate setting, bad timing, worn rings or valves, or incorrectly set valves, or the float level is too high, and or the carb is not venting.
Because of the year and mileage of the bike I tend to believe that you dont have a timing issue, and the odds that those valves are that bad, again, not likely. Reversion in the intake is part of the vtwin design just like push rod motors ticking in the vavle train. So I guess in a long winded way I am trying to say I think its in the carb.
I really didn't use that many of those kits as most of my people just wanted performance carbs. The clip on the needle being set so low, which raises it up, seems wrong, however, again I only set a very few of those kits a long time ago. One question I forgot to ask is how is this bike being ridden? My experience shows that a mild TC, ( 95" 203's exhaust, SE module, SE A/C ) will pull on the average of 38 to 44 mpg. I know people say they get much more, and I sure would like to run a AFR meter on those bikes, as I feel they are lean. However I also know if you take that above bike scenerio and run it at 80mph consistently like I do, ( talking staying at that speed or above for many miles ) the bikes tend to run around 32 mpg.
So again how is the bike being ridden? Now if the float is missadjusted, or the bike is way over jetted, and or the butterfly is missadjusted, upon shut down you will get fuel puddling in the carb at shut down. Also float valve seat. If its not shutting off fuel because of pitting, hardening, etc, it too will allow fuel to bypass into the carb also, ( while running if you have vacume petcock, anytime if you have non vacume )
The jetting for your area sounds within the range, however the larger jet you installed in conjuction with that needle so high really increases fuel. It allows much more fuel to pass the needle jet during the idle/slow speed and transistion period. This with a missadusted carb could allow excessive fuel to be drawn up on shut down and the reversion would push it back past the throttle plate onto the AC as you have spoke of. There is a possibility that the needle was set so high to compensate for the 45 slow jet.

Did the bike ever run ok? After you make sure the float is not set wrong, and its seating the float properly, leave that 48 in and try dropping that needle( raise the clip ) and see how it runs. Let us know how its being ridden also.
 

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Discussion Starter · #9 ·
Jeff S. said:
Lets concentrate on the gas around the filter and in the carb. We know that the difference in pressure from the piston decending is drawn through the venturi of the carb and pulls the gas in. So its either being pulled in and not allowed to pass the throttle plate, being pulled in and the reversion in the intake manifold is pushing it back at low speeds and shut down because of incorrect throttle plate setting, bad timing, worn rings or valves, or incorrectly set valves, or the float level is too high, and or the carb is not venting.
Because of the year and mileage of the bike I tend to believe that you dont have a timing issue, and the odds that those valves are that bad, again, not likely. Reversion in the intake is part of the vtwin design just like push rod motors ticking in the vavle train. So I guess in a long winded way I am trying to say I think its in the carb.
I really didn't use that many of those kits as most of my people just wanted performance carbs. The clip on the needle being set so low, which raises it up, seems wrong, however, again I only set a very few of those kits a long time ago. One question I forgot to ask is how is this bike being ridden? My experience shows that a mild TC, ( 95" 203's exhaust, SE module, SE A/C ) will pull on the average of 38 to 44 mpg. I know people say they get much more, and I sure would like to run a AFR meter on those bikes, as I feel they are lean. However I also know if you take that above bike scenerio and run it at 80mph consistently like I do, ( talking staying at that speed or above for many miles ) the bikes tend to run around 32 mpg.
So again how is the bike being ridden? Now if the float is missadjusted, or the bike is way over jetted, and or the butterfly is missadjusted, upon shut down you will get fuel puddling in the carb at shut down. Also float valve seat. If its not shutting off fuel because of pitting, hardening, etc, it too will allow fuel to bypass into the carb also, ( while running if you have vacume petcock, anytime if you have non vacume )
The jetting for your area sounds within the range, however the larger jet you installed in conjuction with that needle so high really increases fuel. It allows much more fuel to pass the needle jet during the idle/slow speed and transistion period. This with a missadusted carb could allow excessive fuel to be drawn up on shut down and the reversion would push it back past the throttle plate onto the AC as you have spoke of. There is a possibility that the needle was set so high to compensate for the 45 slow jet.

Did the bike ever run ok? After you make sure the float is not set wrong, and its seating the float properly, leave that 48 in and try dropping that needle( raise the clip ) and see how it runs. Let us know how its being ridden also.
A little misunderstanding maybe. My friend's bike is a stock 88" Heritage that has Samson true duals, SE air filter & Dynojet kit (not Thunderslide kit). So a basic stage 1 upgrade. The needle c-clip was set in the 4th groove from the top, I raised the c-clip up one groove thereby dropping the needle & leaning out the circuit.

The bike ran O.K. but sluggish & weak get up & go. This bike was purchased last Sept. & my buddy has complained from day one how gutless it is. As it got colder here in Phx. & air density increased he started getting frequent carb farts when taking off thus the 48 slow jet.

My friend rides pretty mellow when alone or w/ his wife. When he rides w/ me we ride a lot more aggressively. Highway cruising generally around 75-80 mph.

I've never messed w/ the float before, but I've got a co-worker that can probably take a look at it for us.

Jeff, what do you mean by "the carb venting"?
 

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The float bowl must vent or it wont allow the fuel to properly move from the bowl into the venturi. It is mostly vented by a passage on the left side that terminates in that hole on the left side of the carb opening. Notice when you put the backing plate of the AC on the carb there are 4 holes, only 3 are threaded and used, the 4th is the vent hole. I got what you were saying about the clip. Your right, moving the clip up one moves where the tapered portion of the needle is, and therefore can change the fuel ratio during periods of carb operation. Once you get to a certain level it makes no difference. I think you may want to go another groove up. Again you are correct that as the temp dropped ( if it ever does around Phoenix ) the molecules condense and therefore if you were already on the edge of jetting, it could require a larger jet. About 20 degrees is an average jet change. Believe it or not, a bike that runs too lean will also use too much gas because the engine has to work more to produce the same results. If you really just want to try something different, get a stock emulsion tube, jet and probably a couple of shimss, a 185/190 main jet and a 46 or 48 slow jet. Double check the float. Turn the idle mixture screw out 2 turns and start and warm up the bike. When its warmed up set the idle with the throttle plate to 1K rpm. Then fine tune the idle mixture. Re-adjust the throttle plate and see how it runs. I still think its in the carb. And it may have never been set up right.
 

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Discussion Starter · #11 ·
We went for a ride tonight avg. about 90 mph. Yes we really do ride that fast, it's fun. I was riding my 95" FXDL My friend riding his 88" Heritage. His bike is running much better than it ever has since he's had it as far as performance goes. We gassed up at the same time. After about 75 miles I had a little over a 1/2 a tank & he was little under 1/2 a tank. He is pushing a heavier bike & a windshield too though.

We're going to check the float & then also pull the rocker boxes to check the condition of the filter elements in the breathers. I'm thinking the elements in the breathers may be all gunked up & deteriorating which would account for the gritty gunk in the breather crossover. I'm wondering if the head aren't breathing properly if that could cause the reversion issue w/ the gas accumulating in the a/c filter.
 

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Ok, I'll consider anything once. Only a fool is not willing to look at all suggestions before making a decision. Here is my opinon on reversion and breather valves. Lets say that the breather valves were deriorated by 50%, and it was causing blockage, as opposed to running too free which is usually the case. So what could happen? The quick answer is excessive crank case pressure. Where does the crank case pressure go. Usually up and out the breather valves, when that is not possible it usually goes to the cam compartment vent and over to the oil bag. On TC's it would launch the oil dipstick unless you have a digital temp that will usually hold it. After that it really only has 2 other places to go. The crank seal and into the primary and then vent through the mainshaft and then past the trans vent. If that was happening you would lose engine oil, your primary would be overfilled. The other would be for it to go past worn piston rings. This could happen, however those rings would have to be real bad, you would know it. And if the bike was too have valves soooo bad as to allow crank case pressure to over come combustion pressure and pass the valves, well it just isn't going to happen. So I think I would stick to the carb.
 

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AS well that is right there when they used metal and plastic breathers. If they are plastic they could be warped?? Seen that a few times.
Dave you ride fast yea right I am ALWAYS hsve to wait for you to catch up. Heck that was with me riding two up, :hystria:

What are you and wife doing this weekend?? Want to come out for dinner
 

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Discussion Starter · #14 ·
I agree on sticking with the carb Jeff. Thanks for the explanation of the breathing issue.

HDWRENCH said:
Dave you ride fast yea right I am ALWAYS hsve to wait for you to catch up. Heck that was with me riding two up, :hystria:

What are you and wife doing this weekend?? Want to come out for dinner
Now Mister Wrench, you do realize I gave you a head start don't you?! :harhar:
I'll give you a call about the dinner invite.
Thanks.
 
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