Mech

Yup, I've tightened pullers before far tighter than I was happy with, then gone for lunch and they've popped off after a while. Patience.. All the good mechanics are patient.

I looked up some older models and it seem that's standard yamaha for a long time.. Including the ones they state are AC.. They all have the 12v from the key though, and some system for detecting the starter's being used.. Most other pre-EFI makes and models don't use that.. I can guess why they do it, but I can't figure why nobody else seems to think they need it, or why yamaha think they do.. If there are any yamaha trained mechanics out there that know the reasoning behind that I'd love to hear it.

Greetings from New Zealand Eugen..

I was wondering if anyone thought it would be useful, and whether it is possible, that each post in a thread gets numbered. I find myself in cross thread conversations, and it would be real handy to be able to refer someone to another thread, and a specific post in that thread, by number.

Yeah, and even though they now call that winding an anti-kickback, it might still be a winding on the stator much the same as the rest of the charging coils.. I suppose if I looked up the stator it will show the trigger coils hanging off the side, and all the rest as the main windings. I'll have a look. Yes it does. One winding on the stator that's bigger than the rest.. I bet it puts out enough power to charge the capacitor.. https://www.yamahapartshouse.com/oemparts/a/yam/50038985f870021f60a0a1e3/generator

Yeah.. I'm not even sure whether they work off AC or DC. Lots of them have the four wires coming off the stator and going to the cdi. Some have the stator windings and 12volts going in, even though they use an extra 12 v feed in when the starter is going. The ignition controlled 12v in could be to charge the capacitor, or just be for running the neutral/brake switch detection aspects. Either way it should be fairly easy to adapt some other unit, at the risk of straining the electric start I think... And not having the neutral isolation or brake lever over ride on the start circuit.. but that could be arranged.

It would probably be possible to adapt the wiring for a universal aftermarket unit, or a yamaha unit that fits some other model. If that anti-kickback winding puts out a decent ac you could get a simple one that does a four stroke pit bike or chinese bike. Else, there will be a DC cdi off something else that is cheap and would work with that trigger coil. All the yamaha bikes seem to input a starter signal though which will almost certainly be to retard the timing to take the load off the starter. If you use an aftermarket it won't have that feature, and if it's for some small bike the timing advance will likely not suit so well.. If you used a yamaha unit off another model it would have the starting retard in it.

Look the parts up online and it will tell you what they are called, and the exploded pictures will show you where they go. The exploded pictures in parts places are often a lot clearer about things than the photos in some manuals..

Those capacitors should have their specs written on them, but everything else, all the tiny surface mount parts, they are pretty much unidentifiable. They also blow without the obvious physical damage and heat that conventional components show. I'll be mightily impressed if you manage to fix that one Quad.. Good luck with it though.. We all like a trier.

Ha.. The other "mechanics:.. They had a spare washer so just tossed it in there.. Good spotting. Well done finding the wiring problem.. It's funny how often people start throwing expensive parts at things without even checking the wiring or switches..

There ya go..

Ha.. I think that's normal. I don't have one either. It's to stop us patting our own backs.. But don't worry Gw.. I see you're getting plenty of the thumbs up..

Engines and transmissions are generally very reliable. As Gw says, wiring and electronics are probably the commonest breakdown fault. The biggest maintenance issues seem to be the drive line, steering, wheel bearings and brakes. Universal joints, wheel bearings and brake pads/shoes I have probably worked on more than everything else, including the routine inspection and adjust stuff.

I can imagine the feeling Gw.. I hate having to buy things for customers cars on the basis everything else seems right, but without actually being able to confirm the part is crook.. And then the question of whether they bought a second hand cdi but found it didn't cure the problem.. It's a pickle. You sound like you know your way around wiring in general Gw, and you have done all the tests.. except for the output from the stator.. If you've double checked everything, and feel confident in your wiring being what the book says it is, then I'm sure the diagnosis is going to be right.

Well I think we are both looking at the same wiring diagram now Gw, and it shows three wires for charging the battery, and four going to the cdi. Two of those you are calling anti-kickback. I presume that's what the manual calls them. You should check for output of some sort from those two pairs going to the cdi. As I was saying an analogue volt gauge is way more handy for detecting pulses. You can probably still buy cheap little ones the size of digital multimeters that do volts, amps and ohms. They will show a slowly rising needle when you just rotate the crank by hand slowly, where a digital wouldn't show a thing. If the metal tag had fallen off the flywheel you could have good resistance readings but won't get a response out of the trigger. Or possibly the anti-kickback coil. If the two windings are showing something, more than a half volt at a slow crank, then, given their resistance was ok, they should work. If they work, it really all points to the cdi. Some makes they tell you what all the resistances should be between all the pins on the cdi. That would be a mighty complicated table to follow for one of those seven wire things though. You could try a couple of tests though. One common fault is that the trigger transistor fails and the capacitor discharges through the coil as quick as it charges. If you disconnected the coil, the wire should not be showing a voltage until it fires. It should be very intermittent , only once every rev, and a high voltage, with nothing in between. Again, an analogue gauge will show the pulse best. If there is a steady voltage, or fluctuating slightly but constantly, then the trigger is stuck open. I think that's the only common fault we can check for on this. If it was a stator run, ac, cdi we could check the ac voltages rose higher at every pulse as they were going into the cdi. That would verify the voltage stacking diodes and capacitors were working and indicate the capacitor was charging up. I don't think the anti kickback winding is doing that job though. If everything on the bike is right, including the actual physical parts, and there is no output from the cdi to the coil, then it has to be the cdi..

It's strange but I don't get much advertising. I'm a paid up member, but even before I was I never got much, nothing that I couldn't dismiss from the bottom of the page with a click of the mouse. If I sign out and come back as a guest I still don't get advertising, but, then, I'm using linux, so perhaps that explains it.. except.. I boot into windows ten, and I still don't see any advertising, no matter whether I'm signed in or a guest.. Perhaps there is some security setting or spam setting I've got right, or perhaps it's when people look in from their phone, which I haven't tried.. but for some reason, some of you sound like you get a lot more advertising that I do. I reckon there will be a reason though.. Settings I suspect.

Eugen, if you test the stator and the trigger coil resistances from right at the cdi they you are also checking the wiring at the same time. Then check for power and good earths right at the cdi. If all those are good then check for output from the cdi when it gets triggered. You could use a test light with a bulb.. the bulb will probably blow but as long as it's not glowing all the time, but just flashing brightly(and possibly blowing), then it is charging the cd and it is triggering. If you have a read in "looking for a cdi... ", I've just posted some general notes about diagnosing faulty cdi/wiring/stator and triggers, and some other things that can cause it besides electrical faults.

I know I suggested checking for output from the trigger coil on your bike Gw, but I don't remember what the result there was.. If it put out some small voltage then it's probably ok if the resistance checks ok. If it put out nothing it might be because it isn't meant to, it might just change resistance as the trigger goes past. What you need to test that is an old fashioned analogue ohm gauge. You will see the needle jump as the trigger goes past if it's not shorted magnetically.. or fallen off. Digital gauges don't pick it up, analogue and an eye do.

One single spark is generally the cdi. ------------------------------------------------------------------------------------------------- I don't know there's much else to do Gw. The normal process is check the resistance and/or output of the stator and trigger coils, and check they are making it right through the wires to the cdi with a continuity test. Check the output to the coil and resistance check the coil. Then.. Check the switches. Check all the power and earths. Check relays and/or diodes. Inspect wiring for shorts or breaks. Check the wiring's continuity looking for internal shorts. If all the vital things for cdi operation are good and there is no cdi output then it's the cdi. There are always things to watch for though, such as making sure that the voltage or earth you have checked , does actually have a good enough connection to deliver the amps required. Digital multi meters are a bit deceptive there. A test light is better for testing things like that. Another thing is, resistance testing on a stator, and even more so the trigger coil, doesn't verify output. A weak magnet, bad air-gap, metal flakes shorting the magnetic field, can all stop them working. It's always best to actually check the output even when there is no spec in the book for it. Stators put out high voltage, between about 60 to 120 is common, and triggers(if they put out voltage) have about one to five. It varys with make and model, but those figures are enough to verify there is something coming out, and if the resistance is right, then they should work. In the case of these yamahas.. Hmmm.. I think I'd start by identifying whether the wiring loom I had was one that fed 12v into the cdi when cranking, or one that fed 12v through the cdi and then to the start button. Then I'd verify which switches that wiring needed. The colours and shapes of the plugs, and pin positions, and wire colours all combined confirm which exact version we have. Once I was really sure the wiring diagram I was following was the right one for my wiring, then I'd check the wiring for shorts, internal shorts, or breaks, with a continuity test.. with a test light as much as possible..Battery and small jumper and it's easy enough. After that it's do the process described above. You really need to know your wiring loom though because there are diodes and branched wires. They can confuse things real quick if we don't know they are there, and if they are playing up it's hard to click to if we don't know they should be there. .

It seems that year or two were rather exclusive. Which in this case is not a good thing ! Do you have guys that repair car computers there ? Perhaps they can test a cdi with wave generating test gear and an oscilloscope. Bike wreckers ? Fork out $400 for the genuine , which are available.. Buy a whole wreck that sparks for $200.

When the cdi discharges normally it's going through a coil with nearly no resistance anyway.. And, once that wire shorted the engine stopped, so apart from your cranking it over it shouldn't have fired many times. It might be ok still. Repair the wiring and try it..

Oh ok..

If that blue plug there is for your cdi Gw, then that could be why your wiring isn't working out... every book I've looked in has shown black for both plugs. They change(and mention) plug colours for a reason.

Well funny enough there is a service manual.. In the manual section..

Those lockout mechanisms are a bit notorious I think.. They get gunked up and the springs also break..