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Thread: Newbie Question

  1. #1

    Default Newbie Question

    Alright guys, need some expert advice. New to building a bike. Got my 1992 Sportster 1200 to crank over and for some reason it won't fire. I have done a compression test and both cylinders are at perfectly 150psi. The manual says anything over 120psi with no more than 10psi between cylinders, so i assume that's fine. I checked and i'm getting spark, but my worry is that i'm getting too much fuel. The bike was set up for one of those hyper charger air cleaners before this and i changed to a small lowbrow louvered air cleaner. Not sure if that would matter. It seems to be sucking a lot of gas and the spark plugs smell like gas. I attached a photo and it sucked gas from where my finger is all the way down until there was nothing left. Carb was previously completely empty, not sure if that matters. The shop manual is rather vague about how much fuel flow is necessary. If anyone has any ideas or info on the matter, any help is really appreciated.
    Attached Thumbnails Attached Thumbnails Sportster Fuel Line.jpg  

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    Post a pic of your plugs........... Both of them.........

  3. #3

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    Click image for larger version. 

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    was it running before you changed airfilters?

  5. #5

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    It ran fine about 8 months ago when i started the hardtail project. Just finished rewiring it with the sportster treatment kit. This is all new to me and i've been going by the manual as much as possible although this is sort of relatively basic i believe. It cranks fine. So it's essentially just air, fuel, and timing i believe. Just think i may have accidentally flooded it. Not 100% though. Seems to be sucking down too much gas.

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    Are those plugs used? Look brand new.

  7. #7

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    Brand new plugs.

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    Okay so looking at them won't help until the engine has run with them in.
    If you smell gas in your cylinders, something is up. Probably flooded. Let it sit with the plugs out for a while. Then try to fire it again with the petcock turned off, so no more new gas is going into the carb. I doubt it is an issue of too much gas flowing to the carb, issues like that don't usually arise with these systems. More likely it's something much simpler like a maladjusted float.
    Give us as much info as you can and hopefully someone else will chime in here, I hesitate to say too much, especially since I often don't know what I'm doing myself anyway

  9. #9

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    Haha i appreciate it Hatchet. I'll let it sit for a day or two and try it with the petcock off. Might be a dumb question but is it normal for the voltage reading on the battery to drop when you crank your bike over? It drops from 12.8v to around 10.4v.

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    Quote Originally Posted by DRare View Post
    Brand new plugs.
    Oh yea that pic is very helpful....... I'm done with this thread already............

    Best of luck........ You will need it............

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    Quote Originally Posted by DRare View Post
    Haha i appreciate it Hatchet. I'll let it sit for a day or two and try it with the petcock off. Might be a dumb question but is it normal for the voltage reading on the battery to drop when you crank your bike over? It drops from 12.8v to around 10.4v.
    That sort of voltage drop is normal. Those starter motors pull some amps.

    Your carb should accept fuel until the float closes the needle valve. And then the float bowl is full (hopefully to the correct level) and the fuel should stop flowing. The motor actually uses very little fuel starting or idling. If fuel is flowing continuously then the needle and seat are dirty or damaged, or the float level is set wrong. With a CV, dirty or gummy fuel is the biggest problem.

    If plugs smell of fuel, it's flooded. That could be from improper timing or a weak spark. I would go through the timing setting again if I were you.

    Jim

  12. #12

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    Like i said man, I'm new to this whole thing. But I have time so I'll learn. Thanks tattooo.

  13. #13

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    Alright. Thank you Jim. And when you say timing setting you're referring to checking the timing of the cam gears?
    Last edited by DRare; 04-02-2020 at 9:12 PM.

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    That should have a 40mm Keihin CV carb, if original; you can check the part # on the carb to determine if it is Domestic USA (1992-1994 part #27487-92) or a california model (1992-Early 1993; #27486-92)

    http://sportsterpedia.com/doku.php/techtalk:evo:carb01


    this may help explain a bit:
    Harley CV Carburetor Tuning Issues & Troubleshooting
    https://cv-performance.com/harley-cv...-tuning-issues

    1980-1997 ignition:
    Electronic Ignition Systems

    (1980 to 1997) The components for the ignition system includes a timing rotor (timing cup), sensor plate with an inductive pickup, ignition control module, ignition coil and spark plugs. The inductive pickup generates Top Dead Center (TDC of piston) pulses that are sent to the solid state Ignition Control Module (ICM). The ICM computes ignition timing advance and coil dwell. A Vacuum-Operated Electric Switch (VOES) is used (since 1983) to switch between 2 different spark advance curves built into the ICM. 1) These advance curves where modified over the years as indicated by the Curve Letter printed on the modules (such as G, J, K, Q). Some of the variation in the P/N was to designate different terminations of the module cable (such as direct wire or 7-pin plug or 8-pin plug).

    The ICM for these years uses a Dual-Fire Spark system. The dual-encapsulated coil is fired by only one coil trigger wire from the ICM. This produces a spark on both plugs at the same time, regardless of which cylinder is currently under compression. Therefore, there is a dual-spark created when the front cylinder is near TDC and there is another dual-spark created when the rear cylinder is near TDC. (See coil information below)

    The spark advance (curve) starting point can be altered by physically rotating the sensor plate which is located in the 'nosecone' behind the round cover.
    http://sportsterpedia.com/doku.php/t...k:evo:engctl01

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    Quote Originally Posted by JBinNC View Post
    That sort of voltage drop is normal. Those starter motors pull some amps.

    Jim

    That much drop 12.8v to around 10.4v isn't normal.... I deal with off grid solar systems everyday...... A battery is a battery........ That shows a weak battery....

    And I'm not responding to this thread particularly....... I think this needed to be said.....
    Last edited by Tattooo; 04-03-2020 at 5:05 AM.

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    Quote Originally Posted by DRare View Post
    Alright. Thank you Jim. And when you say timing setting you're referring to checking the timing of the cam gears?
    No, ignition timing. I think you have your cam gear timing correct.

    Jim

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    Quote Originally Posted by Tattooo View Post
    That much drop 12.8v to around 10.4v isn't normal.... I deal with off grid solar systems everyday...... A battery is a battery........ That shows a weak battery....

    And I'm not responding to this thread particularly....... I think this needed to be said.....
    When the starter motor is turning, that sort of voltage drop is normal. Let your thumb off the start button and the battery voltage should return almost to its original value. If it stays down at 10V or so, yes the battery is weak.

    Jim

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    Quote Originally Posted by JBinNC View Post
    When the starter motor is turning, that sort of voltage drop is normal. Let your thumb off the start button and the battery voltage should return almost to its original value. If it stays down at 10V or so, yes the battery is weak.

    Jim
    Nope!!!! And I didn't say it had to stay down to 10v...... I said if it drops to 10.4v under a load it's very weak......

    I have never seen any battery that starts at 12.8 then drop to 10.4 for 5 seconds go right back to 12.8v..... Drop to 11.8v maybe..... 10.4 is damn low......

    Please post pics of your volt meter in action.........

    But you might be living in a geographical oddity.... What movie is that from Jesse.......

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    Quote Originally Posted by DRare View Post
    Alright. Thank you Jim. And when you say timing setting you're referring to checking the timing of the cam gears?
    Having spark at the plugs, but at the wrong time, it's not going to start.
    If you were not inside the cam cavity, by taking the cover off, you do not need to check cam placement timing.

    You need to set static timing, you said you are using a manual, take the top rocker cover off (since it is an evo), this will tell you when both valves are closed, locate the timing mark on flywheel, you may need to have it in 4th gear to more easily turn the engine over, follow the book, go from there, and yes follow JB's advice on the carburetor.

    The spark plugs will tell you what is going on inside the cylinder.
    You "read" the plugs by looking at the way they have burn residue.
    A picture of the plugs? LOL! You needed to have a close up of the electrode area so we can see burn color, etc.

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    Quote Originally Posted by DRare View Post
    Click image for larger version. 

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ID:	101611
    Sorry, Laughing my ass off!

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