WOW that was a great explanation! Thanks man. So I had a FULL loss of power on my 08 FLSTSB while riding. It literally just died while I was on it. Nothing, no power, nothing. How would you suggest I start to troubleshoot that? Would a service manual help?
I would check your battery first. Harley Davidson has the manuals on there website for free. You can email me your phone number and I can call you to help. hdrap_1999@yahoo.com serviceinfo.harley-davidson.com/sip/content/document/view?id=5535
So I'm adding a tach to a 97 Sportster 1200 custom. Can I run my tach wire to the opposite side of coil? Opposite side of battery side right. It is a aftermarket tach for a Harley
I think that is the correct way to do it. If you have a dual fire coil I think you have to set the tack to a mode that cuts the pulse in half since the coil will fire on both pistons unless it comes that way. If not it will read double what it should. I hope that's clear enough.
Hola te una harley dyna 1997 y en un tornillo llegan 12 voltios pero en el otro no llega nada de donde vienen los pulsos o como lo reviso tengo chispa en mis bujías pero esta muy débil saludos y gracias espero pueda ayudarme
I check the pulses with a volt meter or a test light. If you have spark then the pulses are there. I’d check for a weak battery and check that the ground is good from the motor to the battery. What problem are you having? If it’s that the bike won’t run I’d spray it with starting fluid to determine if the problem is spark or fuel.
Ccan you tell me how to confirm a hd 31656-07 coil is ok, primary is only 0.3-0.7ohms! Secondary is 1500- 2400 ohms from the manual. How come these values are so small compared to your example, fitted to a hd sportster xr1200x , 2011, efi. 👍🚀
I’d have to look up, in the manual and see what the specs are for that coil. I don’t have that manual. Also, I would wonder how good the volt meter that you’re using to check it is. You can email me your phone number at hdrap_1999@yahoo.com and I may be able to help you more over the phone.
If you're getting 0.03 to 0.07 ohms you may have your ohm meter on the wrong scale . You may be using the continuity setting which is like an arrow and plus sign combined like this ->+ you need to switch to the next scale (200 ohms ) which would have 200 followed by a horseshoe symbol.
i have a question, im putting something together from parts, it has a 1974 engine and the points kit i bought seems funny. it looks like the cam has 4 lobes on it, where as some i see online just have 2 lobes. is that the way its supposed to be? i would think they arent interchangeable
Big twins like the Knuckle, Pan, Shovel and Evo have a single cam with 4 lobes. Twin Cams have 2 cams and each cam has 2 lobes. Sportster have 4 cams and one lobe on each cam. You didn't say what engine you have. If you look on my channel I have videos on the internals of different big twin motors that show the cams. Thank you for watching and please subscribe. It's the least you can do for all this free information. Thx
@@Rapsgarage its a 74 shovelhead, talkin about the breaker cam in the points. the one i got is diamond shaped with 4 points instead of kidney shaped with 2. i watched this video and really appreciated how you broke the information down to fundamentals
Great info as always thank you... So...damn, the secondary should be in spec even w/out the plug wires? I just bought a new coil and straight out of the box the primary side is good (3.7) but the secondary reads 11.29K. The book says it should be 16.5K - 19.5K (1981 FXWG). I know the plug wires will add resistance, but would you say this new coil is bad? And there shouldn't be any OHM reading btw primary and secondary just OL, right? Thanks a lot!
@@Rapsgarage Unfortunately there's no brand name it's off EBAY prob Chinese but it's sold as replacing the OEM coil 31609-80, which I got the specs from the Harley manual. I guess I will just try it and see. well thanks for the reply!
Great video, great teacher. I have a question. I have a brand new coil that tests good. Still can not get spark at the plugs. I have the coil on the bench and connected both wires and new plugs and am using a good battery connected to the coil, in tapping the second terminal i get a spark at the terminal but not at either spark plug. Does the plug need to be grounded? I see you have a vise grip on the plug but it did not look like it was grounded. What am i missing here?
Yes the plug needs to be grounded to complete the circuit. Thank you for watching. If you need further help you can send me your phone number to my email hdrap_1999@yahoo.com It’s easier to help over the phone.
This is the best explanation I have found thank you very much. I have a 73 sportster and get 5.5 and 17k but that is in spec as per the service manual so coil is good. Great video
Thanks a lot for the video and the very detailed explanation. My 00 heritage softail with a carb’d tc88 will shut off once at operating temps. Will not restart unless it sits for a few mins. Figured I’d test the coil. I am a complete novice on testing electrical components. According to the factory service manual primary coil windings need to be 0.5-0.7 ohms and the secondary needs to be 5.5-7.5k ohms. Idk if I’m even testing it right, but I followed your video to a T. My particular coil on the primary side has a connector with 3 pins. How do I hook the multimeter test leads to these 3? Any particular sequence? Also, I tested the secondary windings just as you did in the video. I hooked each lead from the multimeter to each spark plug socket and got a reading of 11k ohms and it raised to 12.5 with a hair dryer on it. I’ve read some people say to test the primary you have to put one lead on the secondary then another lead on a pin on the primary side. Idk what to do. I subscribed by the way!
When you have three leaves like that, that’s the dual fire coil. You measure from the center pin to one side and the center pin to the other side. The center pain gets the power and then the ignition grounds each side individually for each cylinder. I would say it should be a rim .5 to .7 for each side from the center. If you go from outside outside, you should basically get double that amount. As for the secondary side of the coil, I would have to say that if your manual says that it should be one reading and you’re getting something different then it’s probably not good. I would double check your meter to make sure you have a good meter to measure it with. You should never get any resistance from the primary side to the secondary side of the coil. They are not electrically connected. The resistance shouldn’t really change with heat from a hairdryer. I can help you further if you email me your phone number to hdrap_1999@yahoo.com It’s easier to discuss this over the phone then by me texting you. Also, I did look at my manual for my 2003 road king. There were no troubleshooting values for the coil in the manual.
That was a great video thank you very much for sharing great simplified explanation of how the coil work and how to test it. Well I guess it's time for me to go test my coil. Thanks again
Jesus christ brother thank you for this, I've been trying to figure out why I'm not getting spark on my 70 ironhead sporster 900 kick only and this is very helpful thank you again 🤘
@@Rapsgarage I'll definitely email you with my number that would be super helpful much easier to explain over the phone I never had a bike this old it's driving me crazy but the bike is looking really nice otherwise would just like to hear her run again, the gentleman I purchased the bike from told me hasn't ran since 05
I have not found any one explaining the 08 big twin , 4 pin plugin coils , my electrical manual does not show a test procedure it seems to only want to sell break out boxes an other tools . It does state a reading of around 7500 an a lower reading . The meter I have the lowest reading is 200 , then 20,000 , Im not a electronic engineer if you know what I mean , get rid of the electronics an I can fix any piece of it , you get the idea . A few days ago I replaced shifter shaft seal, clutch hub an bearing , C E stator , bendix , comp eliminator an tacked the starter ring , started it 3-4 times the drove it less than 10 miles stopping and starting 3 different times along the way , it set 1 day an then would not start , no fire . Didnt notice any codes , checked crank sensor best I could seemed alright , raised the tank pulled the coil , I had a used super coil , the coil on there , the front cyl came up to a only slightly less reading than the rear (power pin to front an rear pin) my front plug was kinda black looking , rear looked like it was burning good . I tried it with the super coil after removing the battery ground for a while , still no fire . Reminding myself about checking for codes , I found crank sensor sync #18 on the list (could have been from cranking unplugged looking for build up an drop) I erased the code , let it set there a few minutes , noticed the hands slightly move on the dash , touched the starter an it started on the same crank sensor , your guess is good as mine ..........
@@Rapsgarage I checked back to see if youtube had deleted my comment , they have been doing that for no reason , they censored your reply , I never received it ..........
Thanks . When I checked the primary it was fine 3.8 ohms , but when I checked the secondary there was nothing there it was just wide open . Also when I tried the second test for spark i used the bike's own battery and not only was there no spark at the plug but I guess the higher current gave me a spark at the negative on the coil with each on off cycle .I ordered a new coil today .
I can start my evo only using 5 years old champion sparkplugs. I bought two sets of new drag specialist spark plugs and engin doesnt want to start :) have you seen similar situation ?
I have an 07 Roadking sudden loss of power on the highway at 70 pulled over and just turning bout wouldnt start.. i was thinking straight away towards the plugs crank position sensor as im awaiting new parts thought i would check the coil im getting 6000 ohms reading wich im aware is bad and should be 10000 to 13000 like you have stated also. So ive ordered a new coil also and i hope my problem will be solved
What was your ohm reading on the new one? I’m going through this on my 05 road king my old one read 5600 ohms the new one only read 6100 so I think the numbers might be different for efi twin cams.
@@moondogwrecksit9867 they read at around 6ohms and are working perfectly fine as i found out. After buying another coil pack . The test to gst the 10000 to 130000 must be done some other way as i couldnt get any of them readings. My problem was an adjustable pushrod came loose dropping the rear cylinder. Re adjusted and bike back to normal.
I take it you tested your coil by itself and you have spark. If so it would have to be a bad module. First I would double check the wiring of the module. Make sure you have the 12 volt positive wire where it’s supposed to be and verify that your ground is good. What module are you running? Single or duel fire? I hope this helps. If you email your phone number I can call you and help further. hdrap_1999@yahoo.com
I have a 93 FXLR.. been sitting g for at least : years.. has no spark… I have power to both sides of the coil.. if I disconnect the negative side and momentarily ground it .. it will spark., bad module, since the module provides the ground…. thanks
@@chrisrottinger512 I recommend a single fire ignition. www.dynaonline.com/dyna-2000i-performance-ignition-and-coils-kit-for-1970-1999-harley-davidson-carbureted-models-single-plug-single-fire-dc6-5-d2ki-5p/
Use a screwdriver and wave it in between the pick up on the electronic ignition.This will cause the wire that goes to the coil to go to ground and make the plugs spark.
I’ve never had to fool with one. I only have one bike that’s fuel injected and it’s never had a problem. But the ignition system works exactly the same only the ECM is controlling the coil. So if you go through this test and you still don’t have spark when you put it back on the motorcycle I would check to see if you have a pulse coming from the ECM. That pulse would be ground signal as you crank the motor. If you need further help, you can email me your phone number at hdrap_1999@yahoo!.com
Weak Spark because You don't use the capacitor, traditional or electronic module have capacitor 0, 22 uF. This is necessary for charge voltage and disgarge when breaker starts to open
When you're doing the bench test you refer to positive and negative sides of the coil. I've always been told, with a dual fire coil, there is no specific designation for +/- side. I.e. power to one side and trigger/intermittent ground (whatever ya call it, lol) to the other. Also curious, would this test be better performed using a known-good battery so you could actually see the quality of spark? Regardless, thanks for the video!!! I think you may be about the only got on the web that goes beyond the generic ohm test to which, I've found, is not any guarantee a coil is good. Have had several that meter fine but don't work/produce spark.
You are correct that on a duel fire coil the polarity doesn't matter but on a single fire coil it does because the coils are connected together at the positive side. You are also correct that a good battery, instead of the battery charger I used, would provide a better spark at the plugs. Thank you for the kind words and thank you for watching. Please subscribe if you haven't/
@@Rapsgarage I have one more question, is there a standard for plug wire resistance i.e. x ohms per ft. ? I have two wires that won't read below the 2k scale but read .3xx and .6xx the later being 2x longer. That reading strikes me odd in comparison to my other bikes but I have no basis for that other than that comparison. I'm just used to seeing a digit to the left of the decimal point.
@@SayariDunia I would say that it depends on the type of wires you have. I would call the manufacture that made the wires but what you say is correct. The wires will have a resistance per inch that really shouldn't very that much.
That’s a good diagram but; 1st- the voltage/ amperage windings may be backwards. Usually on a distribution transformer, you are stepping down from high v to lower v (12.5 KV to 120/240v as an example 60/1 ratio)The high v coil (primary)has less windings than the low v coil (secondary). In the case of ignition, you are using the coil as a step up transformer ( amperage and voltage are equally and inversely proportional) the coil from the battery would have more windings ( higher amperage/ lower voltage) the coil going to to spark would have less windings ( lower amperage/higher voltage). 2nd- Any induced voltage is the opposite polarity as the applied voltage. In order for the positive and negative poles to be on the same side, the secondary coil must be wound in the opposite direction as the primary coil. 3rd- The energy collapses when continuity is lost ( switch opens ). I am in no way trying to disrespect you. I’m watching this video because I want to work on my own bike and lack the knowledge that you have earned. That being said, I am a high voltage lineman by trade so I thought I would just return the knowledge I was so fortunate to gain from you. I put a 140 c.I. Ultima in my chopper and can’t, as of yet, get it to run right! I really appreciate your videos.
I appreciate the input and don't see it as disrespect at all. I'm in the electrical field as well. I have a electronic degree myself. The primary side of the coil has fewer windings then the secondary side however the primary side winding are of a much higher gauge wire in order to handle the higher current that the primary side requires. The secondary side has much thinner gauge windings and a great deal more of them. The reason for the thinner gauge wire is because the current is much lower and it is also a space issue to keep the coil smaller in size. As you said, when voltage is stepped up current goes down by the the same factor. E=IR. Taking in account the I2R loss will require a bit more current but it's not much more. I did state that the coil fires when you remove the ground as you stated. The magnetic field is created when the circuit is closed and current stops flowing when the magnet field has reached 5 time constancies. One Time Constance is T=LR (in seconds) or 63% of the coils max steady state or full charge. As for the polarity of the coil you are probably correct. This video was to give someone who doesn't understand how an ignition works some guild lines for troubleshooting. I did my best not to get too deep into theory since it only looses most people and it's just not needed. I stand by the accuracy of the information except maybe the polarity of things and that doesn't matter for this video. If you ever need help you can email me phone number to hdrap_1999@yahoo.com. I can call you and help over the phone since it's much simpler that way. Thank you for watching and please subscribe.
@@Rapsgarage its great to watch your videos. Im curious if there is a need to have an upgraded coil if you put an upgraded cam higher lift longer duration something like a bolt in Andrews Ev3?
@@patwrenching9674 The stock coil is fine if you’re just upgrading the cam. When you start increasing compression, you definitely have to get a high-performance coil. With that said upgrading to a single fire ignition and coil helps any Harley run much better overall. It will idle smoother and run smoother overall. I recommend going single fire for all Harley Davidson motorcycles. Harley went single fire starting with the twin cam motor and never went back.
@@Rapsgarage i plan on making a 100/100 ho/ftbls power plant. id like to build an evo to do this. id like to stay away from computers. i just sold my xl883n and my fxlrs114 and now am in a fxr 1989 bottom breather. and its hard to start i dud get some advice about tje voes but not tested it yet. but i wanted to know if just changing to cam higher comp pistons measuring the gasket gaps as per one of your videos will get me into the 80s hp at tbe wheel? then ill take my time building a new / renovate power pant
@@patwrenching9674 I have a 97 Evo that makes 80hp and 90lb/ft of torque. 10:1 Wiseco pistons EV-27 Cam Single fire ignition Thunder Header exhaust CV Carburetor Squish area setup to .030 inch I don’t think the EV-3 will get you 80hp. I’d suggest you run the EV-59 and you should make closer to 90hp
One thing I would add is that in a dual fire ignition system with a single coil, both plugs fire when the field collapses in the primary. The energy from the secondary goes to the path of least resistance which is the cylinder in the compression stroke. The energy jumps the gap and the heat is what ignites your mixture. The energy then travels through your engine and through your second plug and back to the coil. Essentially they're wired in series. The system is simple in design but one bad plug, lead, or cap will compromise the ignition for both cylinders. Voltage is potential between two points, and when you compromise one side you lose your potential.
First, thank you for watching. Ok, I want to address what you said in a respectful way. - The spark ignites the fuel not heat. - The magnetic field collapses and both plugs fire at the same time. After that the current flows to the negative side of the battery to complete the circuit. It does not return through your other plug. If it did, it would have to jump the plug gap a second time. The plugs are not wires in series as they are a parallel circuit. If one spark plug or plug wire is bad, the engine will run on one cylinder. You can give it a try sometime by removing a spark plug or plug wire and start the engine. I do appreciate you watching and commenting and I’m always up for learning something but I stand by the accuracy of this video.
@Rapsgarage I thought that too, but it does go through the second plug. The heat is what ignites the mixture. I had to talk to an electrical engineer at denso because their service manual was incorrect. One bad plug cap was killing spark for both my cylinders. I'm not arguing with you or trying to be disrespectful. I'm just trying to share some information. Also, there is no way for both plugs to truly ignite at the same time because electricity will always take the path of least resistance, and the cylinder under pressure during the compression stroke will have less resistance. I learned this years ago when parrelleling dual DC generators for load sharing.
@Rapsgarage heat does infact ignite your mixture, and this is the reason plugs have different heat ranges. Hot spots on your cylinder walls can cause detonation, and there is no spark present in the combustion chamber.
@@mmholling87 this is from NGK’s website. It is a common misconception that spark plugs create heat. They don’t. the spark plug heat range only indicates the rate at which the spark plug dissipates its firing end heat to the engine. Selecting a spark plug with the proper heat range will ensure that the tip will maintain a temperature high enough to prevent fouling, yet be cool enough to prevent pre-ignition. While there are many things that can cause pre-ignition, selecting a spark plug in the proper heat range will ensure that the spark plug itself is not a hot spot source.
@@mmholling87 heat can ignite your your mixture. That’s called pre-ignition or detonation. These are both bad. Your Harley will run one cylinder. If you needed the second spark plug how would this be possible. Also in my video I only have one spark plug connected to a dual fire coil and I have spark. How do I have spark is the second plug is missing.
