Is my Harley to be no more?

Discussion in 'The Garage' started by Bedger1, Feb 6, 2019.

  1. Bedger1

    Bedger1 n00b

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    When I was growing up my father always rode a Harley-Davidson so its no surprise that after he passed away I found myself purchasing my own a Harley-Davidson FXS 1340 (1982) to remind me of his fun loving, biker spirit. My bike has recently started to let of a lot of black smoke and I'm starting to worry this might be the first sign of my H-D coming to an end, I was planning to visit a local Halfords to pick up some cleaning supplies in case something is burning inside the exhaust and was just wondering is a mainstream store like this would be any good or if there are any products you recommend to do a quick clean at home before taking it a specialist garage that will certainly cost a lot more!
    #1
  2. Maccoul

    Maccoul Bam Bam

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    Sounds more likely you have some carb issues. Black smoke is fuel, blue is oil in most cases. So you might need to have your carb cleaned and rebuilt.
    #2
  3. Bedger1

    Bedger1 n00b

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    Would a carb issue be something I could deal with at home or is it better to take to the garage?
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  4. filmfan

    filmfan Long timer

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    Fundamentally, the black smoke is an indication that the carburetor is feeding the engine too much fuel.
    You can deal with it at home if you have the tools, some knowledge of how carburetors work and experience in taking things apart and putting them back together helps. How much of a learning experience are you up for?
    There are multiple possibilities for what could be causing your problem. For example, it could be as simple as the choke not operating correctly. It could be as complicated as multiple internal parts not working correctly because of dirt or fuel deposits or mis-adjustments. Taking stuff apart is easy, the hard part is knowing what's what when you have things in pieces.
    #4
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  5. Sidecar Jockey

    Sidecar Jockey Bike Doctor

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    I agree with the other posters. The black smoke is because the bike is running too rich, which is almost always a carburetor issue.

    My 1978 Shovelhead vibrates a lot, and after ~500-ish miles it'll have vibrated the pilot mixture screw on the carburetor out. I'll know it's time to re-set the pilot mixture screw because the bike either gets hard to start, or it starts blowing black smoke.

    Check you pilot screw adjustment. Assuming you have the stock Keihin carburetor, the screw should be set to about 1.5 turns out from fully seated. This is a 1 minute DIY job, as long as you have a small screwdriver. Screw the screw in, until it lightly seats. Count how many turns it took, I bet it's more than 1.5. Then re-set it to the factory spec by backing it out 1.5 turns. It's super easy.

    I stole this photo off of the internet, and it's an Ironhead not a Shovelhead, but the carburetor is the same. The pencil is pointing to the pilot mixture screw. If it's too far out, you're running to rich which will cause black smoke.

    commission005.jpg


    This is the first thing i'd check, since it's a common problem on my Shovelhead, and its a very easy fix. As other said though, it could be a problem with your choke linkage or some other internal problem with the carburetor. Maybe your needle valve is leaking, which can let too much fuel into the carb and cause it to run rich? Replacing the needle valve and checking the float height is an easy job, but requires you to take the carburetor off of the bike.

    I think rebuilding a Harley Keihin carb is an easy job and will be your next step, if the pilot screw adjustment doesn't fix your issue. There are some good how-to write ups on the internet.
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  6. Laconic

    Laconic Berserker Nativist

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    Float level/needle seat problems could also cause it to run rich. If the carb hasn't been touched since 1982 it's probably time for a cleaning and soft goods.
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  7. kruzuki

    kruzuki Gear in the Machine

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    Sounds like a carb issue.
    Harleys are relatively easy to work on, the carb is right there, front and center. Do a bit of research, get a shop manual and some basic tools.
    If you own one, you'd better get used to wrenching!
    #7
  8. woollybugger

    woollybugger Adventurer Supporter

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    I've never done mechanical work on cars or motorcycles, and recently I chose as my first project rejetting the carbs on my Honda Shadow. Talk about jumping in the deep end.

    I found the actual carb work very easy. The nightmare was getting things in and out. The Honda is very tightly packed, and everything has to be laid out exactly right, or things won't fit back in. Getting rubber boots and hoses connected was hard when the connections were buried deep inside the works, outside the reach of fingers, and required precise alignment. The 16 year old brittle rubber parts and frozen screws didn't help.

    I've heard that Harleys are much easier to work on, so if you have even minimal skills, I think you'll have no problem. The only thing is, if it's your only bike, you risk being out of a ride while you work on it. I had some down time while ordering a few new screws and bolts to replace stripped ones or while banging my head against the wall and searching for Youtube videos.

    By the way, even though I used the recommended jet kit, I ended up making it worse, with lots of black, gasoline smelling smoke. I finally gave up and took it to a real mechanic, who told me the jets were way too big. He told me he's going to install the correct jets, and I'll get the bike back in a couple of days.

    It was a good experience, and I would do it again. Motorcycles are fascinating feats of engineering, and learning how they work is a lot of the fun for me.
    #8
  9. kmev

    kmev Adventurer

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    If it has an S&S Super E (or G), they are very simple carbs to work on. You can find manuals on the S&S website. Make sure the float is set at the right height on reassembly. If you remove the carb and disturb the intake manifold get new manifold rubber bands. Those things are notorious for leaking air, and can sometime be a pain to get sealed. And don't seat the idle mixture screw too hard or you may crack the seat and will have to buy a new carb body. If the seat is cracked, you can see the crack where the tip of the needle enters the throat.
    #9
  10. Richarde1605

    Richarde1605 Long timer

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    Switch the choke off
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  11. groop

    groop So much to ponder

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    I'm with @Richarde1605 on this. The first time I followed my son on his hand-me-down Sportster it was smoking black pretty bad. Turns out he left the choke on.
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  12. cal08

    cal08 Been here awhile

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    Give it a go. Buy a carb book. The knowledge comes from doing, asking questions, then going back and doing again. Eventually, you get reasonably informed around such things.
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  13. usgser

    usgser Long timer

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    NO. It's just a sign you need to do some normal maint. Even if you wore out the motor, it's infinitely rebuildable. Harley's are only declared dead when the owner gives up on it. Buy the factory shop manual and do the normal/required maint.
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  14. cal08

    cal08 Been here awhile

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    One of the stellar things about motorcycle maintenance is how few tools you need, and how small of a space you need. A small corner in your garage, a little shed with some rope through the rafters. A maintenance manual and a few bucks. A tiny electric heater to keep you warm. You can get a lot of things done just on that. And it all leads to really fulfilling area of maximizing machine performance. It's a great way to spend time. Good luck.
    #14
  15. tennistime99

    tennistime99 Been here awhile

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    As a side note, when my brother took his 1980's era Harley to a dealership the maintenance folks didn't know what to do with it. Unless it had a port to plug into they were out of their element. They recommended he take it to a custom shop.

    May as well work on it yourself.
    #15
  16. Mrrbtc

    Mrrbtc Been here awhile

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    True...I used to call on a big HD shop. The new just out of motorcycle school kids didn't know what a carb was ,not taught anymore.
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  17. BUZZARD II

    BUZZARD II Old Geezer

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    I started laughing when I read about Sidecars vibration problem. I had a '79 Shovelhead, that like clockwork at 600 miles the tach would start dancing around.

    That meant that I had to get out the wrench and tighten the battery leads. BTW I replaced the connectors, wires, nuts and tried loc-tite. Nothing worked. 600 miles get out the wrench. It was a Harley, they don't all do that. But they all do something.
    #17
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  18. yokesman

    yokesman Long timer

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    Carb basics can be found in the FAA publications online ,for the engine as well as basic 4 stroke cycle principles.
    #18
  19. SnoDrtRider

    SnoDrtRider I've been lost here before...

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    When you do get the carb sorted be sure to change the oil and filter as it could be running rich enough that fuel got into the oil.

    Another thing... Id it possible a rodent got into the air breather and made a nest? That could restrict air flow and cause a rich condition.
    #19