Yamaha AT-2 MX Ignition troubleshooting

[@markhall5971]

Dale I dont have the answer for you but I just wanted to say that you are a source of inspiration to all us 70's yamaha owners out here in the UK. I am particularly impressed with the way you explain things that you know, taking time to explain each detail and your humble approach when you don't , when youre trying something new like this . That approach really helps because we know you're a reliable source of information. Good luck with the solution . Mark Staffordshire UK.

[@montana2strokeracer]

Wow, thank you Mark, I sure appreciate the kind words. I am trying to put the best info out there that I can. I most assuredly do not know everything as this problem with the cdi shows. I am trying to read thru some manuals I have and some online stuff to try to find a solution. I have had tons of suggestions from viewers, and I am trying to run all of them down also. I hope to find something soon and will be sure to share my findings. Thanks again Mark.

[@nicksimpson4469]

Machining and Motorcycles! It don't get any better! And you have mastered the art of organizing. Much respect!

[@montana2strokeracer]

Well thank you sir, I do agree, machining and motorcycles, it's a fun combo. Thanks for hanging out with me in the shop.

[@frankdillon6127]

Dale were here for you always, this subjuct is everyones nightnare electrics!

[@montana2strokeracer]

No doubt Frank

[@retromechanicalengineer]

Dale, I tried to follow through your process and I couldn't see anything that would prevent it from running properly. It should work. I think there must be a component fault or mismatch. It sounds as though it cannot gain the advance requirements for increased engine speed. Either the box is providing the wrong curve or there is an issue with the source coil in the pickup breaking down. Such an experiment deserves success, don't give up my friend, there must be an answer. Best wishes, Dean.

[@montana2strokeracer]

No doubt that something doesn't like playing nice with something else. Just going to have to find some specs so I can test the cdi box, but I did swap it out for another like unit. Could they both be bad.... I suppose that's possible.

[@retromechanicalengineer]

@@montana2strokeracer That's right Dale, I'd forgotten that you transposed the boxes. Not inconceivable that two would be faulty, but perhaps not very likely. I wonder if it's worth jury rigging the box from the 360 flat tracker? It might prove the problem is elsewhere if nothing else. Cometh the hour, cometh the man. You'll get there. Best wishes, Dean.

[@Daniel_Martin152]

Hmm. I’m all out of ideas Dale, but I do agree with the others that have suggested to check with a timing light. Good luck mate, and thanks for giving us these videos. See you on the next one. Dan

[@montana2strokeracer]

Thanks Dan, I think I will be using a light, have to find out a way to keep my degree wheel on the rotor while its running.

[@MrVonfelde]

Dale, you've done everything perfectly correct. Every time you've set the timing, you've been perfect, including when you checked with the degree wheel. It SHOULD WORK. I am not sure why it doesn't. But I can pretty much guarantee you something. It is NOT actually firing when it's supposed to, nor when you think it is. If you would have just put a timing light on it while you had the degree wheel on, that would have proved it. Please, please try that. Just to prove it is NOT firing when it should, throw a timing light on it without a degree wheel even. You will see that for some reason, it is NOT firing when those two marks line up. Hook your timing light to a 12 volt battery, and the other lead to the bike plug wire just like a car. Then fire up the bike and point the light at those timing marks. I bet 20 bucks the light will show it's way off. This will take you what, 2 minutes?? Good luck. Robert

[@montana2strokeracer]

Well, we already know it's not advancing even without a light. will get to it all in time. Probably take a break for a while.

[@MrVonfelde]

I explained it all in an e-mail. A CDI does not advance the timing. We set it up with the timing advanced to where we want it, then the CDI RETARDS the timing for starting, and at idle. I believe your system is stuck in the RETARD MODE. Put an automotive timing light on it along with the degree wheel, and adjust the timing to 24 degrees. Then it will run. Takes 2 minutes to hook up the light. Please humor us and try it. Modern tuners use actual timing lights on two strokes all the time. Regardless of what the timing marks say, a timing light tells the true story of when spark occurs with CDI. Good luck, Robert

[@cainbeeping8480]

Frank is right. Electrical is a nightmare. Good luck brother.

[@montana2strokeracer]

Yes sir, nightmare on elm street.

[@markjones95]

Hi again Dale, I mentioned on my last post about the coil & how some CDI ignitions need different connections there. Its a bit awkward for me to explain but here goes. On standard points type ignition you feed one side of the coil with +12v from the ignition switch, and the other side of the coil goes through the points to earth. On some CDI ignitions, for instance the DT400MX I once owned back in the 80's, the ignition coil is fed from the CDI unit on one side, and the other side is connected directly to earth at one of the coil bolts. Without the knowledge of seeing a wiring diagram for the bike that your CDI unit originally came from what I suggest is finding which connection on your coil is the +12v feed from the ignition switch & disconnecting it completely from the coil as it is not required. The now empty connection on the coil is then connected to earth via one of the coil bolts. Please give it a try & report back. Cheers, Mark

[@montana2strokeracer]

Thanks Mark, this system from what I can tell is 6 volt, anyway the secondary coil is. There is no battery. So the only voltage is what is made by the unit itself, like I said I really dont know anything about it. You are trying to tell me but I guess I just dont understand. It runs fine on the point system. I have changed the secondary coil,stator,cdi box and rotor. It all makes no difference, so that leads me to think it is something that I haven't changed, which is really just wires. I am reading about it and trying to learn from others that are kind enough to provide some of their knowledge, such as yourself. I believe it will be a simple thing when discovered. Thank you.

[@markjones95]

@@montana2strokeracer Ah yes, I forgot you are dealing with a 6v system. I think you are on the right track though when you say its something you haven't changed, like wires. Could you check the difference between the wiring diagrams for the original points based system, and the CDI system, especially with regards to how the ignition coil is connected? If wirings not your thing I'd be happy to look over the diagrams to see if theres any incompatibility if you could send me links to them.

[@jamesws3]

Anxiously awaiting your update here!! Hoping I would not be the first so I would see solutions. Glad to share the diagnostic process with you. Wondering what the points do differently than CDI? Could you have a wiring error, something grounding or erratic pulsar signal? Why is timing possibly not advancing? Just guessing out loud.

[@montana2strokeracer]

Got more to look at, probably going to give it a break for a while.

[@jamesws3]

@@montana2strokeracer Sometimes taking a break and walking away is the best course of action. Learned that one the hard way.

[@carlwilson1772]

great film, good perseverance.

[@montana2strokeracer]

Thank you sir, this has been a challenge for sure

[@carlwilson1772]

@@montana2strokeracer My pleasure. I am sure you will overcome it.

[@MrVonfelde]

I know; when you replace an item and the problem remains, it is hard to convince yourself that BOTH items might be bad. However, sometimes that IS the case. It is NOT something you've done wrong here, it's a faulty or mismatched part. Maybe your parts are all bad, and this is a common fault or failure mode with these systems. Maybe you have a part mismatch. THE ONLY THING YOU HAVEN'T CHANGED IS THAT ROTOR. Maybe the magnets in it are not triggering things properly. In the end, if needed, I sent you a link to a totally complete, matched, brand new system for 185 bucks from an outfit in Europe. I apologize: being an engine fanatic, I just CAN'T REST until they run perfect... Hang in there.

[@garyisabelle8078]

Hi Dale, I would be great if you could get or borrow a complete matching CDI system that has been proven and verified to work on another bike. This is a great troubleshooting and CDI learning excersize.

[@montana2strokeracer]

Thanks Gary, yes wish I had one for sure, I don't so I guess I will just keep plugging away. Lots of great ideas from everyone. I sure appreciate your help. Hope I come across something pretty soon.

[@markaddy53]

great video dale sure its stator or cdi wots knackred check readings on stator its summatt or nowt ul get there

[@montana2strokeracer]

Mark, sorry not sure what you are telling me here.

[@markaddy53]

@@montana2strokeracer hi dale i think the cdi unit or the stator is faulty starts up easy enuff but wont rev any higher try changing the stator or cdi box im sure u will figure it out thanks mark

[@JohnnieBravo1]

Hey Dale; please correct me if I am wrong here, but when you used your degree wheel, and got the 44 degrees between -10 and +34, half way is 22 degrees. I think I saw you set the crank to that 22 degrees without re-centering the degree wheel to 0 at TDC. IIf I saw that right, should that 22 degrees have been either subtracted from 34, and the crank set to +12 degrees? Or the other way, add 22 degrees to the --10 to get +12? Or did I miss a step somehow. Totally enjoying this series of videos!

[@montana2strokeracer]

I centered the degree wheel 22 atdc and 22 btdc with the piston stop, that verified Zero. then removed the piston stop and installed the dial indicator, then moved the crank in direction of travel and verified that zero on the degree wheel was the same as tdc. Then moved back the other direction to verify that 2 degrees on the dial indicator was about 20 degrees on the degree wheel. The degree wheel just verified everything I was doing previously with the dial indicator. My goal was to ensure that the stator was positioned correctly on the engine case. Thanks for hanging out in the shop with me.

[@turnburn7851]

Did you get it going? New to your channel so, have you changed or closely inspected all of the wires? Especially plug wire and boot connection.?

[@montana2strokeracer]

Hi, I am still working on it, will be putting another video up soon. Thats what I'm doing now going over the wiring and all the things that I haven't done. I am getting my hands on another coil, and I will make sure the boot is up to snuff. All good suggestions, I appreciate it more than you can imagine. I am going to get this going. It bugs me. Thanks for going along on the ride.

[@davemohney]

I thing all your settings are correct. I think that ignition has low and high rpm coils and i bet the high speed coil is bad!

[@montana2strokeracer]

Thanks Dave, but since I changed the stator coils out, I guess it's possible that both sets are bad, this has really got me stumped.

[@jamesrankin5634]

Hey Dale, love this video its making me think. Now my head hurts LOL . Probably a dumb question but could this have anything to do with porting.

[@montana2strokeracer]

Hey James, my head hurts too, No I have already proofed the porting when I put the point ignition back on and ran it in the video before this one, right at the front of the video. It runs really strong on the point system.

[@Peter-V_00]

Ditch that spark plug cap and use a sparky type, whatever you do, don't use a resistor cap, if you are not sure what you have check it with a meter.

[@montana2strokeracer]

The first 3 coils did have a resistor cap, the last one I pulled from my 360 flattracker did not. I checked after your post. I had not thought of that. Thank you for bringing it to my attention. I am wondering now if I have some resistance somewhere else.

[@Peter-V_00]

@@montana2strokeracer Many moons ago I had a Kawasaki Bighorn do what your bike is doing, on a lark I started moving a timing light around the flywheel while the engine was running, turned out it was firing too often which was why it seemed super rich and would not rev up, put in a new trigger coil and that cured it, not sure if you may have the same issue or not.

[@Peter-V_00]

@@montana2strokeracer Yes the small external coil fires the ignition, but also #16 I believe is the low speed coil and #17 the high speed coil for the spark current for the trigger coil to fire making the spark, your bike is acting like the high speed coil is bad or not there at all.

[@montana2strokeracer]

@@Peter-V_00 Awe its making more sense to me now, thank you for sharing your knowledge. I will keep at it and figure this out. Thanks Peter, I just subscribed to your channel. I have that hard pull clutch on my F5 too. Even the F7 seems harder to pull than the Yamaha's and Suzuki's that I work on.

[@Peter-V_00]

@@montana2strokeracer Thank you for subscribing, I still have a lot to learn about many things, one of my weak points is my lack of editing ability, hopefully I'll catch on. The Kawasaki plastic on plastic clutch mechanism is poor at best, the all steel ball screw conversion really changes the joy factor, sometimes we just don't consciously know why we don't want to ride certain models that we otherwise find really to our liking, rider comforts, machine feedback is a strange thing to deal with sometimes.

[@LarryJohnson-tc7xc]

Sorry dale, didn't have a clue,.

[@montana2strokeracer]

Thats ok, I appreciate the moral support. Thanks for hanging out with me. If something come to you let me know. Not much is coming from my brain, it's a little fried.

[@malcolmbrady1958]

Hi Dale, Your hair does seem as if it is getting Greyer !! Right, I never thought for a second that this engine was not timed correctly, You have done this many times and you know your stuff, No Backfiring, Runs and starts pretty well, just won't rev out, Ran great with Points, changed IG coils, although you have spark, It appears that spark may not be advancing with engine speed, Throw a timing light on, and that way you can verify if that spark is advancing with engine RPM, that will narrow things down even further, The fault has to be one of the components on that Stator, or CDI unit, Keep Eliminating, and I am sure you will get there, Your not far away, Have you got any of your bikes that you can test that CDI unit on, Conduct further Diagnostics if possible on these units, Just thinking out loud mate!! Is that Spark advancing ? If not which component is responsible for advancing that spark, Stator, or CDI, Grasping at straws now, Bigger main jet, just for the process of elimination !! Malc U.K.

[@montana2strokeracer]

Your right, I will be putting a light on it soon, but it is not advancing I can tell that without the light. I moved the stator plate about 1 inch from the timing location, and very little difference. I am wondering now since I added about 6 inches of wire to the cdi box to be able to connect and keep the box under the seat. Do you think that changed the resistance enough to cause an issue like this.

[@malcolmbrady1958]

Hi Dale, I don't think adding 6" of wire would add that much resistance if any, However check with multimeter on all the wires, connections, involved with this Ignition system for Resistance, just for the process of elimination, The coils on that Stator Plate need to be tested, Think its Ohms test with Multimeter but there is a test to determine their condition, remember all these components are 50 years old, You have answered your own question, you know the Ignition is not advancing, Find out how to check those coils correctly, once you get that answer it just leaves one option, faulty CDI. Get in touch with your good friend Kevin Bergan a good source of knowledge in this subject, before you lose that Pony Tail. Thanks for your Channel, Its real Quality, Malc U.K.

[@frankdillon6127]

do you have another CD box, could all be within the box!

[@montana2strokeracer]

I have swapped the stator coils, cdi box, rotor, and secondary coil. Guess it's possible the others are bad too.

[@frankdillon6127]

can you put it back to stock point/cond, just to see!

[@montana2strokeracer]

Already did that, it runs fine on point set up, that was in the video before this one. When it was running at the first of the video.

[@frankdillon6127]

@@montana2strokeracer well that narrows the search somewhat. we need to call the head master at MIT electro physics dept pronto! LOL

[@MrVonfelde]

Again, you have set it correctly. Something else is wrong, but there's a way around it to prove it. About CDI. as you asked: A simple cycle points system does not have an advance system. The better ones, or for larger bikes do, but you know which ones they are as the points plate, or the points cam moves. It has counterweights that move with rpms, and thus provide for timing advance. On the simpler systems, the timing is just set at the max value, and we just run with that. No advance, and no retard. Now, CDI. They all have an "advance" system. I say "advance" in quotes because literally speaking, it's a misnomer. It can't really advance due to physics. Ideally, we want the timing retarded at cranking rpms for better, safer starting, and usually retarded some at idle for a smoother idle. But at higher engine speeds, the engine would run HORRIBLY with the timing retarded like that. Then, on some engines, retarding the timing just a very few degrees is done again at very high rpms. (Like around 10,000 roms) This, some believe, helps flatten the horsepower peak and also help with temperatures at very high rpms. But all in all, ignition timing is extra critical on a two stroke. If it's very far off, it'll let you know quick! However, electrons only travel at one speed, and they can't go into the future. What I'm trying to say is that simple CDI units cannot literally "advance" the timing. Without a crankshaft position sensor and a computer to assist, it's a physical impossibility. Your CDI cannot ADVANCE the timing. So what do we do?? Well, as it turns out, we CAN, through electronics, RETARD the timing. We CAN delay when the spark occurs, and we can make that work. All we have to do is set our timing at the MAX advance point we want, (somewhere between 22 and 28 degrees, depending on the engine), then use electronics to RETARD the spark, or timing, when appropriate. At starting and likely, slow idle, we want to retard the timing back from that max. In other words at starting and low rpms, the CDI retards the timing, at anything above an idle, the timing advances until it reaches our max desired advance degrees of 22 to 28 BTDC that we originally set. So, long story short, a CDI doesn't advance the ignition. We set it at max advance, and the CDI RETARDS it when appropriate from there. HOWEVER, I BELIEVE, FOR SOME REASON, YOURS IS STUCK IN FULL RETARD MODE. That's why it will kick start and run, but poops out above that. If you will just throw a timing light on it, that will prove it. A timing light will show that it is not sparking when those two timing marks line up. All you have to do is hook an automotive timing light up to a 12 volt battery, hook the timing light trigger wire to the bike plug wire, and point it at those two timing marks with the bike running. Then, if you would run it with the degree wheel on, and adjust the timing using the light until it really IS firing at 22 to 24 degrees, it will run great. Robert