Bushyboy's build thread

So I'm in the clymer manual page 180 troubleshooting. Stator coil inspection failed white wire to ground all three got resistance. The resistance between each white wire checked okay, but it says if you get resistance white wire to stator ground replace stator. And rotor coil inspection failed ohm check between green and brown wire. Passed the wire solo to ground check though.
 

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So I'm in the clymer manual page 180 troubleshooting. Stator coil inspection failed white wire to ground all three got resistance. The resistance between each white wire checked okay, but it says if you get resistance white wire to stator ground replace stator. And rotor coil inspection failed ohm check between green and brown wire. Past the wire solo to ground check though.
That's a problem alright.... It's damn rare for a stator to go bad. Check the wire routing where it goes behind the front sprocket. Might have some chafing going on.
 
If it is bad, I don't understand how it's putting out 14.6v worth of charging when revved? Maybe you should check the charging output at the battery again when revved and at idle. I don't think you ever mentioned how you tested for charging before. All you need to do is clip your voltmeter to the pos. and neg. battery terminals, and then take a reading at idle and revved to 3K or 3500.
 
No chaffing or broken wires inside and around sprocket area. So now I'm back to my original dilemma. To get a pma or stay stock.
 
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I followed the manual when I checked voltage and it was fine. I think that the alternator may be charging but somewhere at a certain rpm the coil is not picking up anymore. I don't have points ignition on my model so the pickup coil on the stator controls the signal received. I read about the rare earth magnet many say fixed similar issues I have, but I think I'd rather get a working stator.
 
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No chaffing or broken wires inside and around sprocker area.
Only way to be 100% sure is to pull the harness out in the open and see if short goes away. If it is in fact bad.... it's gonna hafta' come out anyway.
And I'm with 5twins.... how was it puttin' out 14 and a half volts if it's shorted? Sumpin don't add up.
 
I will take it all the way out and check the whole harness when I get a chance. I think it is an issue with the pickup coil truthfully. Plus it's not intermittent so I'm not thinking it is a short.
 
That little pick-up coil is for the ignition. It has nothing to do with the stator and the charging system, other than the fact it is mounted to it.
 
Yes that is what I'm trying to say there is no issue with the charging system. Maybe I said something that didn't mesh when I was trying to explain the way it felt. The bike seemed to drain the battery at idle but the headlight was on. When I checked for 14.6 at 2000 rpm or whatever I had the headlight disconnected like the book says to do. The bike will only make it down the road a mile or two and at around 3500-4000 rpm will miss a few times until it's like there is no fire to the spark plugs and dies no matter what I do. I am just mentioning the pma because to fix the ignition then I will have to replace the pickup coil which means the whole stator.
 
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@Jim I just got the stator off the bike completely the wiring harness did crack in two spots during the removal, but the wires under were not effected and there was no other breaks in the harness. I did conduct the resistance checks again while off the bike and same results. The knuckle buster manual explains the check a little better. It states the one wire that I get no resistance through is the field coil. I did also check the rotor's resistance between the two gold bands in various spots and 4.7 to 4.8 ohms all around. I can't remember where I read it but thought it had to be between 5.0 and 5.5 ohms.
 
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I did conduct the resistance checks again while off the bike and same results.
Still showing a short between the white wires and grnd?
Rotor should be 5.25 plus or minus 10% according to Yamaha's book. So.... 4.725 to 5.775 ohms. Yours is low but within limits... probably getting close to the end of it's life... but still good. And... how accurate is your meter? Mines been calibrated for aviation work, so I trust it. A cheap Chinese.... not so much. ;)

After reading your last few comments, just want to make sure we're all on the same page here.... your stator is part of the charging system. It sends an A/C current to the rectifier. Along with that, the TCI crank sensor is attached to the stator. Yes, that means the stator is used for both systems... but keep the two systems separated when thinking about or discussing them.... two different systems.
The rotor gets power from the regulator to create a magnetic field to excite the stator which creates the A/C current. So the rotor is part of the charging system too. On the rotor is the TCI trigger magnet. So yes, it's also part of the ignition system...but again, keep the two systems separate in you mind... makes it easier to troubleshoot.
You said at one point your voltage got down to 5V before you shut the bike down. That led me (and others I suspect) to believe you have a charging and or battery problem. If your stator winding's are shorted to ground, then you do indeed have a charging problem. And I'm at a loss to understand how you could get over 14 volts when you rev the engine if the stator's shorted. Makes no sense.
And if revving it bring the voltage up to 14+V, how did the batt. voltage get down to 5 volts? Again, I'm a little confused. At this point about all I can recommend is that you replace the stator and go from there. What with all the PMA swaps out there, a "wanted" ad should get you tons of em dirt cheap.
I know your main concern is the bike cutting out at 3-4K rpm.... but until you get the charging sorted, you won't know if you have an ignition problem or low voltage is causing that.
 
@Jim my multimeter is also from aviation maintenance a good expensive one I acquired from the army calibrated years ago though. It has never let me down, but I did doubt it earlier that is why I changed her battery. And a short between white wires and stator case. Also the green and brown wire had no continuity for the rotor coil.

Sorry folks for my confusion I think I took the advice of some and threw it in the mix. When I checked the voltage with the manual I unplugged the headlight and set my idle screw to 2000 rpm; the voltage read 14.6 v. I checked the voltage before my test ride at idle with everything hooked up and it seem to have drained it down to 5.6. I think I checked the battery voltage after I shut it off and it was 11.5. I don't know if there is a charging issue it doesn't seem like it to me other then it doesn't seem to charge over 12 volts after the ride.

The last thing I changed was the ignition coil, because it was recommended to me since it happens when warmed up. I have new spark plugs, new wires, newish battery, new fuse box, and really I am just checking what makes sense to me and what I have read on the forum. I checked the stator multiple times to be sure and the clymer is telling me to replace it. I don't know if that will fix it or I will end up getting another part such as the CDI box. That is basically why I was wondering if it is a good option to go PMA or just replace rotor, stator, and CDI box as needed. The more I read into it the more I want to stay with a stock setup, but hope I am not wrong later on down the road.
 
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The more I read into it the more I want to stay with a stock setup, but hope I am not wrong later on down the road.
Count me as in the keep the stock camp... and if that's the way your leaning, then weigh the cost. If you go PMA, what's it cost for one? Add to that, once you replace the old charging system, you lose the TCI pickup and magnet. Now you gotta replace your Iggy system. What's a Pamco cost? Or you could scrounge up an old points system...
On the other hand, what's the total cost for original stator, rotor and TCI box? I recently pickup up a good TCI box for 30 bucks (and no... it's not for sale;)). You could wind up paying upwards of a hundred bucks for one or get lucky like me. Stator should be fairly cheap if you get one from someone who's done a PMA swap. You could even match drill an old one to accept the TCI crank sensor. You'll eventually need a new rotor. Once it warms up, I'll be offering rewound rotors. You can read about that here. I don't have a price yet... prolly in the 100-125 bucks range.
Reg/Rec.... you can build a good one dirt cheap.

It's up to you.. at minimum, you're gonna need a stator.
 
I ended up doing some online shopping for parts last night. I got a good deal on a used stator and also found a used cdi box. Not that I need the cdi box yet, but figure I can resolder joints or what not. Also found a new rotor for only 70$ so gonna swap it out since the old one is barely in tolerance. So I spent a total of $190 not including shipping. Way cheaper then doing a pma setup for me anyways.
 
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Yes that is what I'm trying to say there is no issue with the charging system. Maybe I said something that didn't mesh when I was trying to explain the way it felt. The bike seemed to drain the battery at idle but the headlight was on. When I checked for 14.6 at 2000 rpm or whatever I had the headlight disconnected like the book says to do. The bike will only make it down the road a mile or two and at around 3500-4000 rpm will miss a few times until it's like there is no fire to the spark plugs and dies no matter what I do. I am just mentioning the pma because to fix the ignition then I will have to replace the pickup coil which means the whole stator.

Does the bike start running again on its own when you drop the revs back down under no load? I had a similar issue on my bike with same type carbs. Even though I rebuilt the carbs and installed an inline filter, and it ran great, over time it began missing at that same rpm range. It would also just die. After spending too much time troubleshooting ignition system (nothing was wrong there), it wound up being the small screens getting plugged where the float needle seats. The cross-over tube and/or original fuel lines downstream of the fuel filter were deteriorating which eventually plugged the screens again. Wound up replacing the cross-over tube and fuel lines. Fixed. Doubt that is the issue, just wanted to offer it up.
 
Does the bike start running again on its own when you drop the revs back down under no load? I had a similar issue on my bike with same type carbs. Even though I rebuilt the carbs and installed an inline filter, and it ran great, over time it began missing at that same rpm range. It would also just die. After spending too much time troubleshooting ignition system (nothing was wrong there), it wound up being the small screens getting plugged where the float needle seats. The cross-over tube and/or original fuel lines downstream of the fuel filter were deteriorating which eventually plugged the screens again. Wound up replacing the cross-over tube and fuel lines. Fixed. Doubt that is the issue, just wanted to offer it up.
It does run smooth through all ranges idle, mid, and full throttle; as well as coming off throttle back to idle. The stator is definitely bad as rare as it is, but I'll only be able to tell you it fixed the problem once the replacement part is on the bike of course.
 
Since I was waiting on parts went ahead and tested my TCI or CDI box whatever it's called. All the diodes check out especially the 4 white ones. I didn't see any cracked solder joints or nothing loose. That thing was a pain to get out since one of the screws was rusted and stripped out.
 

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And the stator just arrived in the mail. Verified resistance checked out and now it's just waiting on the new rotor. Probably take me a while to get the battery box back in position anyways, lol.
 
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