2000 Yamaha Big Bear Quit Today

[Gwbarm]

I pulled out my Big Bear needed to do a few things probably havent been started in a year. Gassed it up charged the battery started right up. I have been using it around the property for this and that. Went to hook up my trailer to pull up to the house while it was idling it quit. Went to start it turned over but wouldnt start. After trying a few more times lost all power. Pulled it up to the house with the John Deere, the first thing i checked was the Universal fit soloenoil from Amazon and it was only a 10 AMP fuse so it does not universally fit the big bear it should be 30 AMP fuse. At the time i remember noticing it but forgot, at the time i had other problems like wiring harness being in a box stuck engine and no spark. when i bought it, yeah i know, thats one ishould have walked away from, but if i go to the trouble of hooking up my trailer and going there, its following me home.

Thats old news, i still need to check it all out see if it lost spark and see if the starter shorted out it was acting kind of sluggish, i replaced the fuse with the spare 10 amp and blew immediately. I will try a 30 and see what happens.

[jen]

Busman's Holiday..LOL🤪

[jen]

That expression originated in the 1840's; most millennials have no idea what it means...LOL...I read a lot...Sometimes i have trouble talking to people my own age..  If you recognized that expression you are old!!!   but Good!

[Papaof3]

Try checking battery post connection check to make sure you have a good ground. Use a meter and set it to DC and follow the power through the wire harness checking for breaks or bad connections at switches and wire connectors Check your fuses. Start simple and check the most obvious things first. Once you restore power check fire, fuel flow, and compression 

[Gwbarm]

Dont know that expression! 

[jen]

LOL...You're 😘Young

[ski522]

I don't recall, but I think you're right that the starter requires something bigger than a 10A fuse. But if it ran and then died, I'd be more concerned with gas, assuming it's fresh. If it is, then I suspect stuck floats in the carb. Remove a side and tap lightly on the bowl, it should help free it up. Otherwise, your carb probably needs a good cleaning if it's been sitting for a year with gas in it.

Edited September 7, 2025 by ski522

[jen]

Seafoam!

[WeeBee]

ALWAYS !!

[Gwbarm]

I put a brand new Mikuni on it last year and always run it out before storing, its possible that some redidual left in the carb could be sticking but it ran so good for a good while and then just died wouldnt start back up and then blew the fuse, no power, the gas is fresh just put it in before i started it. Just went out put a 30 amp in blew immediately. Touched the battery terminals with screwdriver and starter turns so nothing locked up. Time for some wire chasing. 

[johniii]

17 hours ago, jen said:

Busman's Holiday..LOL🤪

I worked on busses for 39 years and remember the term. 

[Gwbarm]

Thanks for the reply i unpluged the wire from the soloenoid and it didnt pop the fuse so maybe something up around the key switch area key switch was replaced a couple of years ago with aftermarket maybe already bad.

[Gwbarm]

I found the problem today, spark plug wire touched the exhaust and melted through. Not sure what other damage it has caused, but now it blows the fuse when i push the starter button, not when i turn on the key, like before, now checking the CDI and coils to see if they got damaged. I may have 2 separate issues going on starter seemed sluggish even before this happened and may have burned up the soloenoid from trying to start it when the plug wire shorted out. There is also an issue with the fan, the fan controller is no longer available and so far i have not found a generic replacement.

[jen]

Oh my!

[Gwbarm]

Pulled the coil out to test it getting continuity between power input and ground thats why im blowing fuses, i will get an OEM, not downing aftermarket coils, it could have been my fault not catching the plug wire so close to the exhaust. Get the new coil and go from there hope it didnt damage the CDI. New soloenoid arriving today will get that installed havent decided if i am going to replace the starter yet although i also have one coming today, not OEM, but i can slap it in there until i rebuild the OEM one .

[ski522]

Good find. Electrical problems can be such a huge PITA, though on ATVs they're not as bad as on a car.

[Gwbarm]

The weird thing about the coil is the resistances were correct, primary and secondary, if i hadnt checked for continuity between power input and ground i would have missed it and still be checking for shorted wires, but i knew something was fishy about it. I was beginning to think it might be the fan control module because it is grounded under the coil bolt.

[jen]

Hmmmm??? your fluke meter only out 9 vdc...Curious...what ohm readings did you get?   Mega, Kilo ohms?...Glad you found that.   Did the coil  get heated causing the insulation failure?

[Gwbarm]

2 hours ago, jen said:

Hmmmm??? your fluke meter only out 9 vdc...Curious...what ohm readings did you get?   Mega, Kilo ohms?...Glad you found that.   Did the coil  get heated causing the insulation failure?

Not sure what you are asking. No coil is not melted i figure when it grounded out something shorted internally aftermarket does not use the same quality of wire as OEM.

No Fluke meter here, Milwauke Tool, the resistance on the primary was 1 spec is .18 to.28 spec on secondary was 6.2-8.2 i got 3.8 which is low but it was like that when i bought it just figured some descrepency in plug cap on the aftermarket unit, but it worked, thats why i am getting OEM this time. Want it to be right i have never been a stickler for name branded parts but i am now some of these parts i have been getting are bad, even for car, i drive a Lincoln Navigator and only install motorcraft parts and now when i get the part box in i have to inspect it carefully to make sure its not a fake motorcraft part, sorry off subject but i am having trouble getting genuine motorcraft parts for my navigator i have stopped trying with Amazon and now go with Rock Auto, no problems with them so far, spark plugs coil packs and brakes i had the same problem with mopar parts never know what you are getting these days its hard enough working on them without having to second guess parts.

[jen]

The Ignition coil puts out 40K to 50k volts.   That being said when I to check for a 460 vac @ 60 hz motor  for grounded conditions typically a I would 'Megar ' test by imposing 600  vac through windings to ground.

You used 9 vdc to ground and saw a low resistance (Ohms) i expect.  I come from a different discipline i guess.

[Gwbarm]

No voltage applied checked it out of the ATV with no voltage im not trying to figure output just trrying to see if all the coils are intact with nothing broken internally. service manual gives a value for that if it doesnt fall within their numbers posted replace coil.

[Gwbarm]

Well, this one has me scratching my head and questioning myself, nothing is acting right. Having the main fuse on the solonoid blowing when i press the start button. Replaced soloenoid and doing the same, unpluged the coil and it stopped blowing fuses but just buzzing at the soloenoid, so i replaced the starter still doing the same, replaced keyswitch, no difference. I decided to start checking voltages, battery voltage 13.2 voltage to soloenid when i turn the key on have voltage to second terminal no clicking just voltage on both terminals, neutral light is on i push the start button, lots of noise at soloenoid neutral light goes off and oil light comes on everytime i press the button. Reinstalled new coil now blowing fuses again. The engine is not locked i can pull it with pull start i take the spark plug out no difference in electric start but easier to pull over with pull start as it should be. I unplugged the pickup coil and i have no resistance there so i have to go in and replace that, but im not sure that is all my problems when they go out it just doesnt spark not keep the starter from working. Never seen anything acting quite like this. Some of you professional mechanics out there with electronic expierence,any advise would be greatly appreciated, it went from running great to idling thats when it quit. 

[Gwbarm]

I unplugged the coil , pickup coil , stator, fan controller, still blowing fuse with new keyswitch. The one thing iforgot to unplug is the fan i will try that next , after that all thats left is the CDI and the starter circuit interrupt relay, but usually when that goes out you get nothing, no click no humm nothing when you turn the key. Not sure about either starter should still turn even with bad CDI. Got to be a direct short somewhere in the harness.

[Gwbarm]

Working on the Big Bear again today, for the first time when i hit the start button smoke came out from under the front of the engine, looking closer could not really tell where it came from. Reached my hand under there and sure enough the wiring harness was laying on the exhaust manifold so i moved it and the starter turned over the engine. Sure i had found it, tried again and never turned over the engine again just clicking like before. It was so deep under there i could not get to where i could see anything. Kept trying wiggled the wires nothing but buzzing soloenoid.

 

Decided i had had about enough of this, not having fun, its got to be fun and rewarding or not worth the effort, time to take everything back off. Took the tank of just 8 bolts, they didnt want that thing going anywhere. I could see a lot better but couldnt really see where it had burned through and really needed to see the whole layout. Not like i hadnt seen it before, i put it all together from a box o parts, but many machines have crossed my path since i did this one. You can see the main harness in the middle of the photo and then it branches off and goes over the exhaust i can see where it touched but no exposed wire. So now i need to unwrap it all and see which wires are damaged, just looking looks fine hopefully it will be obvious once unwrapped.

 

 

[WeeBee]

Good Luck on the Hunt for the break/short!!

[jen]

Well if it any consolation, They rest of us are impressed with your "stay -with-it"...

[Gwbarm]

Thanks for the words of encouragement! 

[ski522]

A break wouldn't blow fuses; it would have to be a short. I find it odd that two wires would somehow short under electrical tape unless they are being twisted or pulled on at a common point, like the harness getting pulled when turning the steering. I found a circuit diagram that might help. I'm not sure of the year, but I doubt it changes much.

One way to troubleshoot is to use a multimeter with a continuity setting. Put the black lead on ground, then use the other lead on a plug to see if it grounds out when it shouldn't. This isn't a perfect test if a relay or other component needs to engage to complete the circuit, but it's a good start. Make sure the battery is not connected when doing this too to be safe. 

https://www.manualslib.com/manual/830446/Yamaha-Yfm-400-Fwa-P.html?page=33#manual

Edited September 22, 2025 by ski522

[Gwbarm]

Found the wire its not even burned into, it is the Br/L brown and blue goes to the main switch in the on position from there to the main fuse, turns to R/W and continues to the CDI. That explains why it was blowing fuses when switch turned on , not doing that now but still buzzing at solenoid. Not much damage really shouldnt be causing a problem, once i removed it off the exhaust. Got to dig deeper. Although there are some very suspect areas. To be honest the whole bike is a suspect area, but it runs so good and pulls like a buffalo, although probably the slowest quad i have ever ridden. It does need a new harness but not available and i will not buy a used one, been there done that. I suspect what happened i was doing a lot of sharp turning to back up and hook up my boat, and must have snapped the wire holder loose from their hold down which alowed the wire to fall on the exhaust.

I know this is probably boring to most. I only post to bring you along on the journey of troubleshooting wiring so it might help others in the future.

 

 

[jen]

Well it proves to keep looking.  Glad you posted that. Pictures help.  Tape wrapped wires keep them together but don't protect much.   I prefer point to point wiring as opposed to Printed circuit boards.