2004 Yamaha 250 Bear Tracker

[Randel1 3]

Hello, 

I have a 2004 Yamaha Bear Tracker in the shop for repair. I have the service manual but it doesn't have all the information I need to fix the problem. I need to know the voltage output of the stator charge coil and pulse or trigger coil at cranking speed. The wiring diagram color code doesn't seem to match and that is compounded by the fact that the wiring harness CDI connector is missing so I have 7 wires that need to be connected to the CDI. I can not find a circuit diagram of the CDI which tells me where the pulse/trigger coil connects or the charge coil connects. The other 3 wires (black ground, orange ignition coil, and r/b ignition kill sw) also need to be connected. The CDI has a single 8 pin connector and has a P/N 4XE-00 F8T19871 -1122 number on it and I believe it to be OEM. However I think the Stator and pulse coil are aftermarket items. I have resistance tested everything and it all seems to be in spec. but I don't want to miss wire anything and cause damage. Any help would be greatly appreciated. 

[Frank Angerano 837]

I just realized you posted this with your make and model.   I have a bear tracker so any help you need i will do my best. I will take a look and get back to you on the spec for the stator and pick up coils.  
Mine is a 2000 so some big differences in the wiring.  
let me see what i can find. 

[Randel1 3]

Thanks Frank, I appeciate your response, quite frankly I did not expect to hear anything this soon.  I'm looking forward to learning what you find out.

[Frank Angerano 837]

Ha, thats one of the best things about this forum! Who wants to wait for answers? Its almost as bad as waiting for parts. 
 

[Frank Angerano 837]

See how this matches up to what you have as far as color and quantity. 
its from an 2001 my atv. 

[Frank Angerano 837]

Your charging wires from the stator should be 14-15 volts at 2000 rpm. 
The stator resistance between phases of the stator (non rotating) should be 0.45 to 0.55 ohms then test each of the stator wires one at a time to ground with the tester in between looking for continuity. If you have continuity on any of the three phases to ground then its an instant fail. 
Pick up coil resistance 189 to 231 ohms What color wires are on the pick up coil W/G&WR?

[Randel1 3]

I managed to pull up a schematic that seems to match this machine. YMF250XP I will take a closer look at the wire colors in the morning and get back with you. I should be able to wire the connector as per the wiring diagram and I will again check and verify the resistance values of the 3-phase charge coil the CDI capacator charge coil and the Trigger Coil. I am going to assume that the drawing depicts the wiring harness connector that plugs into the CDI. I would like to be able to take a voltage reading from the trigger coil and capacator charge coil at cranking speed but I don't know what values to expect.   

[Frank Angerano 837]

If you do the testing on the stator and the pick up coils and they fall within spec then they are good. 
The only voltages you should look for are from the stator. For the  trigger coil/pick up coil, you can put your tester on the two wires and spin the flywheel by hand and as the magnet passes the coil you should get a reading.  
Take a look on eBay and I'm pretty sure you can find new plugs for the harness.   

[Frank Angerano 837]

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F303393055758
 

 

[Randel1 3]

Ok, here we go.

I have 3 trigger coils. The one that is in the machine and two new ones. The one in the machine is color coded w/r and w/g and has a resistance of ~ 213 ohms. One new trigger coil is color coded with solid red and solid white wire and its resistance is ~495 ohms. The other new trigger coil is color coded with a solid blue wire and solid green wire and its resistance is ~ 466 ohms.

I have 2 stator assemblies which have 3 phase coil resistance of ~ .6 ohms and infinity to ground. The CDI charge coils of one is color coded with a solid red wire and a black wire the other is color coded with a white/blue wire and a solid red wire. They both measure ~ 2 ohms with infinity to ground.

I also have 2 ignition coils with spark plug (resistor) caps. The primary resistance on both is ~ 1 ohm but the secondary with resistor cap are different one being 7.8 K-ohms and the other at 18.6 K-ohms.

My wiring harness rings out fine and all my ground to frame and battery check out.

I am getting .5 to .7 vac output from the trigger coil which seems to be about right, and the exciter coil output seems to be low at about the same .5 to .7 vac. I think I should be somewhere in the 50 to 70 vac range in order to properly charge the CDI capacitor.  To summaries, it appears that I have two bad stator exciter coils, the difference in the ignition coils concerns me also. I can not evaluate the CDI until I can verify it has the required pulse and exciter voltage inputs.

What compounds the problem is the fact that I have ordered and returned several new CDI’s as well as stators in the past for other machines and they were out of spec. or defective when received. When it comes to electrical parts it seems that they are not adequately tested before shipment and the parts house suppliers have no way to test them plus, I expect that returned parts are just put back into inventory and sent out with the next order without testing. Needless to say, I am skeptical about the reliability of most aftermarket electrical parts but a lot of times OEM parts are no longer available so you are forced to resort to aftermarket parts. 

I sometimes wonder if I’m just getting too old and cranky to deal with this BS.   

I also want to add that all the replacement parts look like OEM parts and are supposed to be replacement compatable.

[Randel1 3]

It appears that once again I have been foiled by receiving bad parts from the supplier. The spec. calls for the Pick Up coil resistance to be 189-231 ohms and the charge coil to be 270-330 ohms. It seems that my pickup coils are ok at ~208 ohms but the charge coil on both my stators are the same at less than 1 ohm. What's the chance for both of them to be shorted out and reading the same low resistance? 

[Frank Angerano 837]

If your getting 213 ohms on the trigger coil then its good. If your not getting any short to ground on the three phases Thats good but it sounds below spec @0.6?   

Ive never been successful in testing a cdi other then trying it on another atv of the same kind. Ive also tried other non oem stators that claim are direct replacements but did not work. 

Do you have the spec on the exciter coil? 
Caltric makes a decent stator and ignition parts, i have them on my bear tracker and have been working for over two years. The cdi was bad also but i took my chances on a used one on ebay and it worked great.

I would sort out all your parts and get rid of anything or at least put it aside for now what is not oem or questionably not good. Do the proper testing as you have been and verify that the parts are within spec, label and keep the good stuff. 

If your getting frustrated then walk away for a bit, this is a thing i always tell people. Its a frustrating process but rewarding when you get that spark going. 
 

Age is all mind over matter! If you don't mind it don't matter ! Lol You got this!
 

 

[Frank Angerano 837]

Are your tester settings correct? Both coils testing that low is not a coincidence. It's probably ok.  Whats the spec on them ?

[Randel1 3]

Measuring pick up coil on 2K scale and it reads ~ 308 ohms. Measuring the exciter coil on 200 ohm scale and it reads less than 1 ohm. However the exciter coil is a single pole coil of wire on the stator and consists of about 25 ft. of 20 AWG magnet wire which should have a resistance of 1 ohm or less. I am wondering if the specification written in the repair manual is a typo error which calls for a 270 - 330 ohm measurement.

[Frank Angerano 837]

I don't know if the manual is wrong but i would think that the coil is ok.  
 

As far as the plugs etc and cdi where are you with that and everything else wire related.  Kill switch wiring?
 

[Randel1 3]

LOL at this point I think I have one foot nailed to the ground and I'm just going in circles. I have checked and double checked the harness and plug wiring, then checked them again. Everything rings out according to the schematic. 

One of my previous jobs was working in a boat repair shop rebuilding and repairing outboard and inboard motors. We always had a stockroom with new parts on the shelf and if we had a questionable stator, coil, or ECM I had a new one on the shelf as a backup to check it out. Thats not the case now, I have no known good parts to substitute which makes relying on accurate drawings and published specs.  especially important.

I even suspected the flywheel had become de-goused and lost some of its magnetic flux but thats not the case because I am getting about 9-10 VAC out of the 3 phase charging circuit at cranking speed. If it's inducing a voltage into the 3 phase coils it has to be doing the same for the CDI charge coil.

[Frank Angerano 837]

Agreed with regard to the stator. My guess at this point is a bad cdi. You cant really test them. Once a diode goes bad its over. Unless there is moisture inside you cant do anything about it.  

Edited December 7, 2019 by Frank Angerano

[Randel1 3]

I am also leaning toward the problem being the CDI. The one on the machine looks to be OEM and I have a replacement that I ordered and received a couple of weeks ago. It is an aftermarket knock off and as I said before, I have received several in the past for other machines and had to return them because they didn't work and I think this one is not so good also. I ordered a Caltric which won't be here for 7-10 days so we will see what happens when it arrives. I'm still miffed about the low voltage reading out of the stator CDI charge coil. 

Anyway Much Thanks for your help and input, I'll let you know the outcome when the CDI arrives. The Bear Tracker will be put on the back burner till then and it's on to the SuckSusie quad runner which has fuel supply problems, it should be a breeze. 

[Frank Angerano 837]

In don't know or think the caltric will work but I'm hoping it does.  Either way keep us posted.  

[Randel1 3]

Ok, I know it's been a while since I first posted the problems I was having with this ATV. I would like to report that I have it up and running like new. I got the wiring streightened out and after repeated returns of defective CDI units I finally got one that actually works. I went thru about 6 of them before getting one that works. The problem is they were all the same part number and they all said that they were compatable. From past experience I have found that more times than not there is defective inventory in stock when it comes to electronics. It seems that the suppliers have no way to verify or test these parts prior to shipment. This is particularly troublesome with CDI units as they contain electrolitic capacitors which are prone to fail in time due to their physical make up and design. This failure is compounded if they are not charged and discharged over long periods of time while sitting idle in some stock room. It would be helpful if the suppliers could rotate their stock periodically to have them re-tested and certified or there needs to be a shelf life placed on this type of assembly. The other possibility is that they may be getting the bad part returned and just putting them back into inventory without verifying if they are serviceable or not. What ever the case it makes troubleshooting and repair a nightmare when you repeatedly get defective replacement parts.