Ignition system testing, Magneto coils, Points and CDI

Troubles with your motorcycles ignition? No spark, poor spark or performance? Here is how to test the ignition magneto coils found on all types of motorcycle engines, points or CDI. Learn how to test them properly. Diagnosing intermittent & no spark. Also a demonstration of temperature affecting ignition coil performance.
Also check out more here! www.thejunkmanadv.com/magneto...
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0:00 - Intro
0:07 - Read the service manual
0:54 - Parts of an ignition system
1:26 - Tools needed
2:16 - How a basic ignition system works
4:24 - Common misconceptions
5:25 - How you test the stator coils
8:23 - How to determine if the coils are good
8:51 - (Demonstration) What affects ignition coil resistances?
11:43 - Thoughts & Conclusions
#ignitioncoil #testing #repair

[@thejunkman]

If this video helped you considering giving "THANKS" ❤ it goes to help making more videos like this.

[@rustmanoriginal]

One of the best videos I have seen for magneto systems.

[@custompipes1]

Great work thejunkman, well explained, direct and concise and as you say, teaching us how to fish. Cheers.

[@mikehanlon]

The ending is amazing. My favorite line, "it's giving me a reading of 1.6, well what does that mean? Nothing if you don't have the service manual".

[@thejunkman]

Pretty much, since it is dependent on the windings from the factory's spec.

[@frankdavidson9675]

it dont mean any thing with a manual only that it not open that coil is nothing but a lenght of copper wire wrap around a piece on iron so as you apply a voltage it magntizes that iron the secondery winding is wrapped around that same iron so the magnetizem creates a high voltage inthe secdonary winding which go to distribtor and the `spark plug so there is not a lot to see with the ohmmeter

[@AaronMartinCOOLVIDEO]

Great stuff man thank you for making this video. I love messing around with old motorcycles and occasionally does type of thing does happen.

[@aderiley6592]

Excellent video 👏 Thank you for making and filming this lesson in such a clear and easy to follow way, much appreciated 🙏

[@aaronspencer1880]

Nice video, Junkman! May I please add that the resistance measured at 8:08 will vary significant;y depending on the make/model of multimeter used. Some cheaper meters may exhibit over 1 to 2 Ohm resistance in the leads and probes points alone. Different meters use different voltages to test for resistance and this will also significantly affect the result, especially when trying to test resistances at these extremely low levels. The best way to test coils is via an inductance test however, rarely do service manuals provide such data nor would many home mechanics have an inductance meter. Just food for thought before anyone decides to replace a coil because it is a fraction of an Ohm out of spec :)

[@bobbyj6387]

Thanks for the video, very helpful and informative. We just bought an old 73 Yamaha CT1 175 that has no spark. Now we have somewhere to start!

[@jpurcha]

Just bought a KE100 Kawasaki - no spark. Will test the coil tonight.

[@timmykneller8987]

So do I need to get a manual? Lol. Thanks for the video!

[@buttole]

thanks brotha, ill be doin this test tomorrow fingers crossed

[@anthonyearnst9376]

Excellent video. Thank you. I learned a lot

[@JoeyMcGovs]

great info my friend, thanks for the knowledge!

[@steelcantuna]

This system is similar to my 1957 Simplex Servi-cycle. Thanks for posting.

[@thejunkman]

This system is very similar to almost every breaker point ignition.

[@SUPERDUCKcromobe]

well presented, thank you for good information

[@tkmofficial1285]

Great Video brother!!!

[@joeyr2523]

Great video and handy as I have a f11. However not sure if I have a lighting coil problem. Right hand side blinkers work front and rear brake switches work front left blinker stays on solid and rear left blinker and head lamp don’t work at all help! 😀

[@TG5879]

Wow. Extremely informative.

[@tjpeters99]

Great video. Well presented and very illuminating.

[@thejunkman]

+Timothy Peters thanks

[@abalter]

Excellent video! Thank you!

[@bashirhussain2115]

Can a point system converted to cdi ? My bike honda cg 125 1990 model point. Now the point are not available in pakistan new honda bike are cdi system.

[@poolman8676]

hi junk man, how do you test the CDI on a 85 2-stroke Honda CR500?

[@paulhaines5755]

Have you every used a single cylcinder CDI on a twin or a twin cdi on a triple engine (two cycle)? Will it work?

[@bordelonchris7373]

Can you do a video on setting point gap and setting timing with a strobe light on an F11?

[@joshsamuelson1793]

Great vid.

[@UpInSmoke54]

Best way to check a stator is with a DVA(Direct Volt Adapter) adapter, static test (resistance )like the one shown in this video are not always conclusive, something you will get a good reading but the stator could still be bad. With a DVA the test is made with the stator still in the machine, turn the engine over and read the peak volt with the DVM. The problems with DVA test is there's not always data for this test in the service manual.

[@geoepi321975]

That's not the best way, the best is with amp clamps and oscilloscope amp curves under load

[@ricardoheleno8670]

Hi, First place, thank you for the video. Second place I would like to contribute with some good practice hints regarding resistance measurements. When measuring low resistance values with tight tolerance intervals you should take into account the multimeter cable resistance. You can do it easily just by joining the probes. The cable resistance value must be subtracted from the final measurement. Also, the contact resistance between probe and wires is also significant in this measurements and proper contact must be ensured.

[@TheSpannerLab]

Thanks Junkman. That was easy to understand. Well done. I don't suppose you could do a little vid on the role and testing the condensor? Thanks either way.

[@thejunkman]

+Lozz Mitchell I could and might however its kinda futile as the condenser is cheap and easy to replace, and you have to remove it any ways to test it.

[@plusblood5101]

Thats awesome video

[@marcrichter9345]

Thank you sir!!

[@firworks]

Nice video junkman. People are terrified of troubleshooting anything electrical but it's really not difficult nor does it require an EE degree. Also what happened at the end there? Cat broke down the door?

[@thejunkman]

Flubbed my lines and the wife behind the camera noticed it.

[@aakritipradhan2230]

♥️♥️♥️♥️♥️🔥🔥🔥🔥🔥😍😍😍😍🌄🌄🌄💋💋💋💋💋💋♨️♨️♨️🌄🇳🇵🇳🇵🇳🇵🇳🇵🇳🇵

[@clintonfaraon9646]

Im actively building a yamaha 175 enduro with all different parts. The frame and wheels are 1969, engine is 1974, gas tank is a 1972, with new misc parts mixed in.

[@cfcasazza]

Great Video. Thanks. I followed your procedure and it turns out I need a new magneto ignition coil for my 1975 KS 125. Do you know if there are any electronic ignition conversion kits for the old kawasakis since I am unable to locate a replacement coil. Thanks

[@mikeangelastro7648]

Good video

[@doctorash27]

Hey junkman, great video. I have a question. On a points system, while using a test light should I see a flashing light at the wire that goes to the coil? Could you elaborate on testing a system with a test light? I’d appreciate any input.

[@thejunkman]

You might or you might not. Adding a light bulb in the system ads more resistance that the coils are not designed for. I know what you are thinking and it would be an inconclusive test. This is why the manual's state to test the resistance of the coils to determine if they are good/bad.

[@ridingstuffed]

Very helpful

[@xxxxcoolhandluke]

Excellent

[@scalecraft4663]

exellent ! thanks

[@Purple_Ytub]

i converted my motorcycle stator to battery operated and I'm having problem about lost of electricity during running position and there is something building up on the positive side of the battery. What do you think is the problem?

[@thejunkman]

I am not sure what you mean you converted the stator to "battery operated" the stator is what gets its current induced via the spinning magnets.

[@chriswalsh2175]

I would like to know more! So in this service did you have to change that coil I would think so

[@thejunkman]

I use this for demonstration purposes only but yes to use this Magneto and stator plate I would have to replace the coils by simply unsoldering them and soldering the new ones in

[@artbentley4887]

I have a 1976 ke100. I can’t seem to find an ignition coil. Any idea where to find one . Thanks

[@thejunkman]

Ebay, saved search.

[@anthonym2277]

My system looks identical to yours on my 1976 KM100. I'm getting 3.0 ohms on the black wire. What does it mean when resistance is too high? Pretty sure it's identical to a ke100 which calls for 1.1 - 1.6 ohms.

[@thejunkman]

It means the wires are degraded and causing higher resistance.

[@davidsteele9764]

I have recently purchased a 1983 KX80 and was wondering if it would be alright to just buy a coil Magneto and CDI off eBay would they work the same as original

[@thejunkman]

Given the vagueness of "magneto and cdi off ebay" I would probably say no, unless it states it will physically fit on your machine.

[@andrewziegler2608]

1.6 could be good for a cheap meter with resistance in the wires, you gotta test that first to get a baseline

[@romuloparrilla1998]

I DO HAVE A 1980 KAWASAKI KE 100 WITH BREAKER POINT IGNITION THAT WONT START,THE LIGHT ON THE NEUTRAL SAFETY SWITCH TURNS ON EVERY TIME I TRIED TO START IT. SO IS THAT MEANS THAT MY IGNITION SYSTEM IS WORKING???MY SPARK PLUG DONT HAVE ANY SPARK TOO.SO MAYBE MY COIL IS BAD THEN?PLEASE HELP THANK YOU

[@thejunkman]

+romulo parrilla no, the neutral light has nothing to do with it. Test all the coils. I have those values on my website.

[@erichess7491]

Hello I have a 94 kx 80 it fired and ran shut off then it would fire and die I pulled the plug and had weak spark put a new plug in and had no spark after that I checked the kill switch it was a litte corroded I disconnected it and still no spark and checked all connections nothing bad. any ideas

[@thejunkman]

+Eric Hess check your magneto cold resistance per the manual. They are probably near the limits.

[@mahmudulkarim3539]

Hello dear,my cub50 honda don't get current to spark plug.what is problem ,I want to know this.

[@thejunkman]

Did you watch the video? It shows you some ways to diagnose the problem.

[@andrewweston2253]

this vid was a great help! I do have a question about soldering the condenser- do the coils have to be soldered to specific contacts on the points or can they just be joined and soldered to one contact ? 74 KS125 same unit as you're showing

[@thejunkman]

I am not sure I understand as the condenser connects with a fork connector to the points. Its only job is to briefly store energy ,that is induced from the coils, to jump the points when they begin to open, which fires the plug.

[@andrewweston2253]

thejunkman My condenser has 3 wires soldered on. On on side of the fork the wire from the excited coil and the black output lead, the other side of the fork has the wire to the points soldered on. I have been told that I can join these wires and solder to the top of the condenser

[@thejunkman]

Sounds like you can.

[@timgordon6978]

Will a voltage regulator Kaze no spark situation on a Yamaha 1300

[@nickblackwell7937]

Voltage reg pretty much just regulates the voltage

[@bordelonchris7373]

Great vid thanks. I see you're demonstrating on an F11. Where can I get a flywheel puller that will pull the F11 flywheel with 4 bolts? The Kawasaki tool 51001-259 is obsolete and the 3 hole puller won't work. Thanks in advance.

[@thejunkman]

Yes, it is an odd pattern. I have a really old Motion Pro universal puller that has holes that fit this pattern (among other patterns) but it is not made anymore that I can tell. This one looks close, but have no experience with it specifically. www.amazon.com/Universal-Motorcycle-Flywheel-Puller-Suzuki/dp/B005SUUB6K I have used other "Pit Posse" branded tools/pullers with success so the quality I have experience is decent. You can make your own out of plate steel and some bolts. A 2 bolt puller will work using only 2 of the 4 holes, just have to be patient and some persuasion to bust it loose. Using only 2 bolts will risk stripping the threads as the load is only spread over 2 rather than 4 bolts. If you strip it is not the biggest deal as you can drill and tap to a larger size if needed. Hope some of this helps.

[@bordelonchris7373]

@@thejunkman Thanks. Thought of making one. Also looked at the 2 bolt puller. You think the 2 bolt timing gear/steering wheel puller will work? That Pit Poose might work too.

[@thejunkman]

It might, as long as it is slotted so the distance between bolts is not fixed.

[@wankyler]

My magnet coil is a bit oily due to some leakage. Would that spoil my magnet coil? Right now I can only start my scooter with a kick-start, not the ignition switch.

[@thejunkman]

No. Oil will not effect operation.

[@Jimmyzb36]

Please do a video on the Yamaha AT3 dynamo.

[@thejunkman]

I would need one for demonstration. But a manual and the basics shown here will help

[@ProjectRedfoot]

Duuuude, I kinda get it now!

[@thejunkman]

Great! Then I did my job well.

[@whydahell3816]

I have a 2000 Polaris scrambler 500 HO 4x4. I've changed, stater coil, pulse coil, CDI box, voltage regulator, ignition coil, and in line fuses also key switch. I have bypassed the key switch and handle bar on/off slide bar starter switch. Have spark from black wire CDI box, still no fire. I checked ohm resistances on all parts new, and old. Still no fire. I can only figure it's a grounding issue. Ignition coil negatives are not getting the correct reading on ground side top and bottom. I don't know what to do except change EVERY wire. Thoughts pls

[@thejunkman]

Are you following the procedure outlined in the Polaris manual? That second to last sentence might be where your trouble is, however I don't understand what you mean.

[@whydahell3816]

Thanks for the reply man!!! I test the ignition coil tab and get good reading. I test the coils ground and I don't get, .05 I get a higher reading. So, what do I do to get a proper group reading? I cleaned up battery, solenoid, and ground cable going from engine to frame. I don't know what else to do. Unless new ignition coil is actually bad. (it's happened to me before with new parts).

[@whydahell3816]

yes I am following procedures. To the T

[@thejunkman]

Well if you can't get the ohm reading from the "new" coil, per the manuals instructions, then I would say you have a defective part. I am not intimately familiar with your quad so I have to assume you are testing it correctly.

[@whydahell3816]

I'm very grateful for the reply man!!! I've been stuck on this for a while. I'm testing correctly as far as I can tell. Ground from coil to one test lead, other lead to engine case. I just don't know what else to do to get a proper ground reading other than change the coil. So, I ordered a new coil, and also a used "working " one from eBay. All I can do is try them at this point I'd guess. I'm a machinist /millrite for 26 years, no electriction lol

[@donjayamaha6174]

Hi is a bike alternater have permanent magnets for the rotator

[@thejunkman]

Yes. It is how the field coils get current induced into them.

[@007380]

The heaop running is probably whats causing my 750 shadow to stop running after I drive about 5 miles. It will start after I let it set for about 30 minutes.

[@thejunkman]

Heat? Yeah probably. Grab a manual and test your coils. www.thejunkmanadv.com/repair-and-service-manuals.html You can purchase a manual using an affiliate link, helps me keep making videos.

[@josephvarona9773]

hi the junk man how can you tell by looking at the coils what is lighting,charging and magneto coil? thanks

[@thejunkman]

You can't. Yoy will have to follow the wires, or read your service manual and it will tell you.

[@josephvarona9773]

@@thejunkman ok thanks, and one last question how figure it out if the coil is damage by looking at it?

[@thejunkman]

You can't, you need to test it like I did in the video. This will require the manual for the specs.

[@aftab277]

Hi there mate, I've got honda activa scooter and what happens is everytime i pressure wash for cleaning the scooter won't start for almost 10 to 15 mins and then it starts after it dries off a bit. Also when on highways when i ride it for too long i feel alot of resistance in the engine and loss of power, i guess it's the coils that are heating up and causing the problems ? What are your thoughts on this? Should i replace the coil? I already cleaned up the carb, sprak plugs and air filter though !

[@thejunkman]

+aftab malvi I would use some dielectric grease on all connector. That will help with you water problem. The drivability problem is jetting related. I have a video on that

[@aftab277]

thejunkman you mean inside the coil assembly?

[@thejunkman]

+aftab malvi no the electrical connectors

[@glennspeeds]

Hello! How do you know which coil is for the ignition and which one is for charging the battery. I guess the manual will tell but can you tell by just looking at it?

[@thejunkman]

Yes, which ever one goes to the points on this style of ignition or the one that then goes to the CDI box.

[@glennspeeds]

thejunkman thanks man! I have a Honda atc Big Red that fouls spark plugs regularly. At first I thought it was the carburetor but now I think it is from a weak spark. Have you ever seen a bike that had spark and would run but the weak spark wouldn’t let all the fuel burn?

[@thejunkman]

Yes, and usually it is a mag coil problem or a point problem.

[@glennspeeds]

thejunkman ok thanks again! I will check it out.

[@tomb8430]

Hey Junkman, awesome videos... is there a way to test if the CDI advance is working on a Honda 50/70? What would the procedure be? Could you explain or make a video? That would be awesome... cheers!

[@thejunkman]

+Tom B i am not aware of a test for it

[@tomb8430]

So is it the case that the CDI firing sensor just gets bolted into place near the flywheel, and that's the end if it? No adjustment?

[@thejunkman]

+Tom B no, it is not adjustable

[@tomb8430]

Thanks Junkman! Keep up the good videos !

[@kevinstearns4198]

question i replcad the stator and cdi in my 87 kx 250 it backfires the head gasket is leaking i think its sucking in air? ideas? it leaks in the front oil from the gas.

[@thejunkman]

Replace the head gasket first before trying to diagnose any other problems. The rest of your sentence doesn't make sense.

[@kevinstearns4198]

i know its leaking oil from the premix. i will replace the head gasket first thank you.

[@thejunkman]

Kevin Stearns Let me know how that works out.

[@kevinstearns4198]

i will

[@kevinstearns4198]

i replaced the head and base gasket and the sob still backfires.

[@Ex-fk4nr]

Hi...My motorcycle stator looks a little bit differerent there are 3 coils one of them lools like those on your stator but two other looks like those coils that are used on transformers....there is no pickup coil or break point....one day it sudently stopped working I wanted to check the pick up coil but could'nt find any pick up coil anywhere any idea how can I find that...thank you...nice video by the way

[@thejunkman]

Your service manual will outline the procedure and specifications specific to your bike for testing. Sounds like you have a CDI equipped bike which the testing is the same, just have to know what the ohm readings should be. If you need more help, post a picture to the comments on my website. Link in the description.

[@Ex-fk4nr]

I don't have a service manual.Have a look i've send some photos on your website....thank you

[@sailasmanja9775]

Whaal this is great

[@naveedaka]

can you tell me how bike with a dc cdi starts even without a battery

[@thejunkman]

The flywheel contains magnets that pass by the coils of wire wrapped around an iron core. The magnets induce current into the coils, the current is then briefly stored in a capacitor and then that current is released to the primary windings of the high tension coil to then be induced into the secondary coil, stepping up the voltage strong enough to jump the spark plug gap to reach the ground.

[@TAGCREATIVES]

6v coil or 12v coil in a 2 stroke motorcycle, how to tell a difference?

[@fauxtrot47]

Ritesh Singh Rathore He explains it in the video, The 12v coil will be always be larger in size because it has more copper wire wound around it than the 6v does. If your bike has 6v lights and 12v ignition the smaller is your lighting coil.

[@jorgeacampos.5274]

Thanks.

[@hambrisahrum3534]

i have a problem, new regulator very hot and my new batery just buy easy to loose charge and kill my batery...when i charging it's batery fail to charge....why can give info to me what is that problem,...my stator got problem or another, i just change many part for my motorbike, new regulator,new cdi,wiring already check, new batery, ...sometime exzose come out white smoke...my virago xv250..

[@thejunkman]

This post is very hard to read. I am not sure your question or what your trying to communicate. I understand your battery is draining, but that is about it. With the bike off put a volt/amp meter between the positive terminal and positive lead and see if there is any current draw with the key off.

[@gingerramsunder9544]

@@thejunkman how.to.set.dkw.points.3.cyl

[@myvehicle5602]

I have just stuked with installing the ignition system of honda cd 90. I have disassemble every part of the engine and reassemble them after cleaning and applying lubricating oil on some parts.I am a self learner but now I have a trouble with installing ignition system. I set the statar and then I don't no hove set up wiring that are ahead on my proccess. I would be very much thankful for you to if you can help me to finish this work by giving me information that are required. I want to know how statar wires connect to the next component and what is that next component.then how the spark plug connect to the battery and what are the other component related to the ignition system that I want to be aware, such as mechanical breaker,coil .......I would be much oblidge if anyone can help me.!

[@thejunkman]

Go here www.thejunkmanadv.com/repair-and-service-manuals.html Scroll to the "Typical Honda/Chinese Clone CDI wiring" Ignore the color coding but it tells you which wire and connector goes where.

[@myvehicle5602]

thank you!

[@cluelessbeekeeping1322]

Hoverboard! I remember I had one as a kid! I broke my collar bone 3 times using one! It was so much fun!

[@thejunkman]

Lol, ok.

[@lh98]

can a coil go bad in a way that throws off the timing of the spark? I am working on a kawasaki engine for a john deere riding mower and it has spark but seems to be firing at the wrong time blowing flame out carb indicating early fire. key isn’t sheared and magnet lines up with last edge of the coil at tdc so i’m baffled

[@thejunkman]

No. Your problem us jetting. It could be a rich condition for some reason.

[@lh98]

thejunkman thing is the riding mower just up and died while mowing along with no symptoms except the occasional backfire some days. will not start or fire at all other than a backfire and flame out the carb. if it’s got fuel compression and spark shouldn’t it have some ignition at all? valves are fine, very slight leak which I just lapped the valves to correct but nothing enough to cause this. even rich the gas should ignite some in the power stroke i’d think

[@thejunkman]

That is the thing, it is igniting the fuel and spitting it out the carburetor. I guess it still could be a magneto coil problem not firing all the time under compression. Usually those motors don't have a spec to check like indicated in the video.

[@thomaspencak5811]

I have a 1980 Honda C70 with a 6 volt system. I have an original Honda manual for my bike and it does not state the stator coil Ωfor the magneto coil or the battery charging coil. If you have that in one of your manuals, can you reply with it. I am not finding any available magnetos as new and may need to rewind the coil, when I determine the problem. I have changed every other ignition component and still have a low voltage going to the spark plug. Enough of a voltage to show on an analog meter at about 60 volts, and still does not feel to good going thru my finger, but not enough to create a spark. Thank you.

[@thejunkman]

I am assuming you mean you have a CT70. The Honda factory and the Clymer manual list 1.3k ohm for the primary coil. Typical range can be +/- 10% of this value. This must be tested with the breaker points open and the condenser wire un-hooked or you will get an in-conclusive value. Also your symptom could be a failing condenser, since you will have the flywheel off to do the other test, you might as well replace it and it is not a bad idea to replace the breaker points themselves as the contacts might be worn. You can perform a test on the ignition (spark plug) coil as well. Primary coil resistance 2.1-2.3 ohm (black wire to ground) & Secondary (high tension wire to ground) coil 9-11k ohm. However this test can sometimes be in-conclusive as the secondary coil is highly dependent on the primary coil. All these can contribute to a weak performance at the plug. You may want to check out CHP (classic honda parts) they have a lot of this stuff brand new, or suitable clone replacement parts.

[@thomaspencak5811]

@@thejunkman I have a 1980 C70 Honda motor bike, AKA a Cub70, or Passpor 70

[@thomaspencak5811]

@@thejunkman I have replaced all other components including diode, ig. Coil, condenser, plug, confirmed cut off at ig. Switch and kill switch.

[@thejunkman]

@@thomaspencak5811 Ok, well they are the same engine either way.

[@thejunkman]

@@thomaspencak5811 Then test the primary coil (under the flywheel), that is probably the culprit.

[@naveedaka]

how does the length of trigger ridge affect in four stroke bikes flywheel

[@thejunkman]

Not familiar with that term

[@naveedaka]

thejunkman ..sir...i mean four stroke bikes have timing trigger rigdes on outer side of flywheel...but they differ in legth ....some are small...some are long...why??

[@thejunkman]

I would have to see a picture of what you are talking about. Post one to my website in the comments.

[@naveedaka]

thejunkman ok sir...thanks

[@RisingSun0203]

So if the coils test out ok could a no spark condition be a failed condenser? How do you test for that? Nice video, thanks.

[@thejunkman]

There is really not a good test for those. Replacement is the best option because they are cheap. First check for grounding issues though

[@Paint0nBrush]

why do you use DC ohms instead of measuring pulsed DC impedance?

[@thejunkman]

Because that is how the test is done per the procedure in manual. Nearly all coils in magneto ignitions are tested this way, irregardless of bike make/model. The spec or range of a "good" coil will be different (obviously) for a different model of bike, but tested just the same. All that is happening here, and this is explained in the video, is magnets in the flywheel are inducing current into the coils as they spin around them. Improper resistance within the coils by a break in the wire, degradation of the insulation between the wires and core will cause a change in this resistance and thus induction will not occur.

[@112879jcarlos]

some of these bikes don't use DC voltage, they Pruduce AC voltage.

[@paulhaines5755]

1992 Kawasaki KE100 magneto exciting coil - do you think resistance of 2.7 (spec is 1.0 to 1.6) would cause no spark condition? Considering rewinding myself to see if I can get it to work. Sorry to bother you with more questions.... Thank you so much for this vid. It's great.

[@thejunkman]

By your test result yes, the resistance is too high.

[@paulhaines5755]

@@thejunkman Thank you so much! Just for experimentation sake, I unwound the wire from the coil. I tested the end to end resistance and it was about 2.7 OHM (the same as when loaded on the bike/assembly). I then cut off wire until I reached an end to end value of 1.6 ohm and it took removing approx. 25 or 30 feet to get there. The remaining wire is about 50 feet long and produces 1.6 ohm. I don't know what this means, really but I thought you might appreciate the information.

[@jawadaloribi8929]

You can help me .. I have a Yamaha Majesty 250 model 2014 and there was a problem in the scooter .. I appeared code number 76 and since that does not work .. Do you know only what this number 76 symbol .. Please help me I am tired .. Greetings

[@thejunkman]

I have no idea what a code number 76 is. It has diagnostic codes? Never heard of that in scooters. I would check the service manual and see what it has to say.

[@jawadaloribi8929]

@@thejunkman Thank you ... I would be thankful .. Waiting for your reply

[@thejunkman]

No, you check your service manual that you bought for the bike. We don't have access to this model here in the USA.

[@jawadaloribi8929]

@@thejunkman Thank you

[@bliad2]

hi. What can cause burning the coils?

[@thejunkman]

Burning the coils? I am not sure what you are asking. Coils can fail for a number of reasons, most commonly is the degradation of the insulation between the core and the wires (winding). This material degrades from age and vibration over time, especially in 40+ year old bikes.

[@bliad2]

thx for your respond. by burning i mean, the coils where melt down (2 of 8 if im not mistaken) and they where black, like they where overheated.

[@albycortez1992]

My flywheel makes noises when i shake it. Is that bad?

[@thejunkman]

Yeah, means a magnet is loose.

[@wessley29blakely]

Two of my magnets are black what does that mean?

[@thejunkman]

Probably just a variance in manufacturing

[@damonwagenaar7029]

How do u get the stator off

[@thejunkman]

Usually just 2 or 3 bolts hold the stator plate on.

[@tomken5919]

This was awesome. Thankyou

[@Bubbasoffi1]

Always test your lead resistance first to obtain the proper coil resistance result.

[@michaelllewellyn7215]

Good video but the test leads could well be 0.2 ohms each so short the leads and remove that number from the test results Also the wire to the coil may or may not be includes in published results I think we can say that coil could well be OK Maybe cleaning the coil earth connection could well lower the resistance a bit . I do not think the coil itself is going to be at fault if it is only fractionally above the spec. If it was low then yes it could have shorted turns

[@yoursstudybangla]

Plzz post the tvs xl super st coil connection

[@thejunkman]

I have no idea

[@jpurcha]

Ok 1976 Kawasaki KE100, Ignition Coil (specs for primary winding 1.9~2.3 ohms, got 2.6 ohms); secondary winding (spec. 10K ohms, got 10K). Is this ok? Ignition magneto coil (specs. 1.3~1.5 ohms, got 3.2 ohms ..... no good. Be kind and rewind.

[@thejunkman]

The ignition coil is probably "ok" as it is really hard to get an accurate reading on the primary winding because it is also dependent on the secondary. Your problem is with the magneto coils as they test out of spec. Basically all the "energy" is generated via induction into those coils first so if they don't test in spec then it really doesn't matter if the ignition coil does or not.

[@craigwilson8255]

Awesome... the factory manual doesn't show how to test the cdi unit or whatever they used to be called. Cool

[@matbogbrygmail740]

Very helpful video. I have been struggling to find help on troubleshooting my '74 MC1M, which has no spark. What's the best way to communicate with you?

[@thejunkman]

Start by replacing the points and condenser if you haven't already. Then proceed to test the coils resistance per the manual .

[@matbogbrygmail740]

@@thejunkman Is the Clymer manual good?

[@matbogbrygmail740]

Also need to verify what year mine is. The VIN on the head tube is MC-507593. Do you have a way to verify year and model?

[@thejunkman]

Yes, it is nearly identical to the factory manual, except it has more pictures and more explanation and the grammar is better. Buy one here if you like. tinyurl.com/mc1manual

[@thejunkman]

It is a 1974 MC1M

[@georgefox8539]

Hey Junkman - love all your videos. have watched all the barn fresh series multiple times as I work on my 1971 Kawasaki F6. question on this video: my service manual spec for Magneto ignition coil resistance is 0.5 ohms. I am getting a reading of 1.7 ohms. is that definitely the Primary coil that needs to be replaced? just want to avoid buying an un-necessary part and all the soldering if it isn't. will the two leads of a "good" primary coil have resistance of 0.5 ohms also so I know before installation?

[@thejunkman]

In short, yes. The a "good" coil will be within 10% of the stated value (.5 ohm). Too far on either end of that 10% range means it is just on the fringe of being about to successfully induce a charge from the magnets whizzing by the coil.

[@georgefox8539]

thanks JUNKMAN!!

[@georgefox8539]

@@thejunkman so I just bought a supposedly "NOS" Primary coil part number 21049-013 on ebay and it is reading 1.5 ohms across the two leads (not installed yet). I am interpreting your comment that it should be reading 0.5 ohms so it is not a good part, right? I also get 1.5 ohms when I measure across the original Primary coil leads.

[@SinnerSince1962]

I had no idea the limit on resistance could be so minuscule and cause a problem. We're talking tenths of an ohm??

[@thejunkman]

Depends. Typical is 10% +/- of the target value.

[@2strokeowner]

Good

[@thejunkman]

Thanks. Be sure to check out other videos and my website for more information on this topic.

[@vulwatin]

anyone notice the hoverboard on the wall....

[@thejunkman]

I did 😉

[@yahiyashaikh9146]

thanks to inform.. I'm trying to restart my old junkbike...

[@marienoeldavrincourt3825]

I'm

[@thomasevans1428]

Brokene coil wires mean bad stator

[@naveedaka]

please reply sir

[@rampagemototv2023]

newbie here

[@Jack-ns5zc]

This is great but i own an awkward bike made an awkward company that don’t supply manuals for their bikes. Great

[@thejunkman]

That sucks, because unless you know what the correct ohm ready should be, you won't know if a coil is out of spec. As stated in the video, it is the wired that is wrapped around the core that determines weather the magnets will induce a charge to them.

[@Jack-ns5zc]

thejunkman I’m gonna look for a new one from another bike maybe, it’s just a pain because i didn’t wants to. But lifes not fair

[@mdsoto3893]

What is your Facebook page?

[@thejunkman]

facebook.com/thejunkmansadventures I also have a website with more information. www.thejunkmanadv.com/

[@TiberiusStorm]

I thought black wires were generally a Ground. 7:31

[@thejunkman]

+Shaine MacDonald "Generally" is the operative word. The color of wire is bike/application specific. Most vintage Japanese bikes are BLACK or BLACK/WHITE (striped). Always refer to the service manual for proper info, thus why I stressed this at the beginning.

[@TiberiusStorm]

I always use a service manual!

[@thejunkman]

+Shaine MacDonald then your good to go!

[@joe241able]

i am so sick of hearing about magneto my bike needed one its finaly in lol

[@frankdavidson9675]

you dont need a ohmmeter to check a coil if yoy suspect a coil???? pull spark plug wire off inset a scewdriver in t he plug wire hold about 1/4 inch from eng spin eng, you will see spark jump from screwdriver to the eng that is all it can do no problem if no spark you have a problem check keyway in flywhell and shaft they will break some time its rare that mess up the timming need to replace key in the shaft if you take flywheel off check the points and condenserif points are pitting replace condenser clean or replace the points

[@thejunkman]

If you read your service manual it will explain how to test just as I did. The other stuff is addressed in the video.

[@muhammadtashkel2986]

The point bike is better that CDI

[@demonrathunter]

good God is this science class or were you trying to show what the title said????

[@thejunkman]

+duane brown did you watch the video? The testing is there in the video, understanding the science helps understand the test. I'm teaching you how to fish rather than gving you the fish.