Need help with a 1987 YFM 350

[bwatson]

I'm new to the forum and I am having issues with an older Warrior that I only can hope someone has the knowledge I need. Don't have a lot of money so just trying to shorten the list of suspects. So thanks in advance!

ATV was running like a champ even at it's older age when I got it. Prior it sat for awhile but did run for a few weeks before I purchased it.

I would get out and ride on it for an hour or so and when you come to a stop and sit to long... it would stall out. When you did get her started again, she would start running ruff, sputter and backfire. When you gave it gas, it would just stall out like it was sucking up air. Then next day.... start right up and run great but would still do the same thing. Sputtering and backfiring when giving gas got worse and worse as the ATV got hotter. This was also intermittently happening.

Also, this ATV seems incredible hard to pull start, even with the decompression arm engaged.

Symptoms:
1. Battery Drain
2. Very hard to pull start, but is possible.
3. Even if you jump the battery with a truck, still cranks over very slow and eventually will just heat up the jumper cables, the starter gets hot and the battery will go dead.

Good:
1. Fuel, Carb and Intake Manifold (boot)
2. Spark Plug
3. Replaced starter with a good used motor
4. Brand new battery.

Thank you for any advise you can give to point me to the next part i'll need to purchase. :tup:

 

[alex456123]

Bet the stator is bad.
Caltric offers one for 60 bucks on eBay. Its what I am running in my 87.

 

[bwatson]

Stator and Hard to Pull Start

Bet the stator is bad.
Caltric offers one for 60 bucks on eBay. Its what I am running in my 87.

Thank you. Going to order one and give it a try.

But do you think the Stator can cause the ATV to pull start really hard?

 

[alex456123]

Thank you. Going to order one and give it a try.

But do you think the Stator can cause the ATV to pull start really hard?

Yup, it will cause weak spark, making it hard to start. If you are talking about how hard it is to pull it over, there is a decompression lever on the front top of the engine on the valve cover, or at least there should be.

 

[bwatson]

Runs but dies when throttling fast

Ok..... couldn't get this ATV to jump with my jumper cables from the truck. But did get it to pop start by towing it with the truck. Pull start recoil plastic pulley inside was getting ripped apart, so left it off.

The ATV ran great, sat in idle perfect! Took it around the yard a few times slow and fast. Then I let it idle for about 10 seconds... then got on it. I made it to second gear with heavy throttle and then she went back to the same situation....almost died, just sputtering at idle and when I gave it just a little throttle, it would just backfire and want to stall out.

I do believe that the Stator could be the culprit, but with my low budget, i'm sill hoping this sounds like something else.

Again, this ATV was running great for about 2 weeks when we got it... no problems... just started doing this. And every time I "pop start" it, she will sit in idle, run great and also run alittle bit around the yard until I get on the throttle.

Thanks all for your assistance! :thanks:

 

[bwatson]

Kick start instead of pull?

On this 1987 Yamaha Warrior YFM 350, can a kick start be added instead of the original pull start assembly? I'm In need of a rebuild kit for the pull start but can't find anyone who sells it and I can't afford 150.00+ to get a used or new one.

Any suggestions?

Bye the way... I am reading as many posts on this website as I can to better aid myself. I'm used to go karts and cars... not ATV's.

 

[moby]

before spending all the $ on parts, have you ohm'd the coils to test if they are bad?

ignition coil. orange to base .36-.48 ohm
spark lead to base 5.44-7.36 ohm

charging coil white1 to white2 white1 to white3 .70-.86 ohm
source coil green/white to red 270-330 ohm
pick up coil blue to yellow 171-209 ohm

 

[alex456123]

before spending all the $ on parts, have you ohm'd the coils to test if they are bad?

ignition coil. orange to base .36-.48 ohm
spark lead to base 5.44-7.36 ohm

charging coil white1 to white2 white1 to white3 .70-.86 ohm
source coil green/white to red 270-330 ohm
pick up coil blue to yellow 171-209 ohm

Never mind, I'm a retard.

 

[bwatson]

Checked Coils

Thanks for the info Moby! I did check what I could see and found that the ignition coil was definitely bad... but have one on order already.

As far as the Stator... i'm reluctant to remove it from the ATV because i'm not familiar with ATV mechanics. The wire color code you gave me most certainly helps but doesn't seem to match the Stator wire harness outside engine. So not sure how to test the Stator from the outside of the engine or what connecters are correct for each "coil purpose" in the Stator.

With my lack of knowledge... I would need pics of my ATV outside wiring harness or the Stator getting tested to see where I need to be for each coil.

But, this is what I've done to test this ATV recently:

1.) Removed and tested Starter by jumping it with the truck. Spins fast and freely.
2.) Pop started it yesterday... the battery showed 11.40volts but while running showed 12.66 volts. I let it idle for 10 minutes and shut it off. When attempting to restart ATV, the battery appeared to NOT have sufficient charge when hitting the start button... turned engine over slowly for about 5 times then clicking from selenoid. Also, she never did run correctly....she started up running ruff and backfiring when touching the throttle. (probably bad ignition coil?)

So apparently, until I get that Ignition Coil changed, I believe i'm stuck in the mud. But i'm sure I will need assistance further as I go. I am attempting to rebuild it, just need to wait a month to free my cash. Then I get to play!!!.

Thanks guys.

 

[bwatson]

Out of the mud... but still repairing.

Received my new Ignition Coil today. What a difference... she started running way better. The rest of the issues it seems turns out to be the carb gas/air mixture and the idle screw.

Now she will even pull start as long as I use the decompression lever. Still need a rebuild kit or a new plastic pulley if anyone knows which replacement will work in my ATV.

The next thing I need to deal with is the ticking at the top of the engine which I can assume are the Valves. Headed to YouTube to conquer that battle.

Thanks for all your help so far. :tup:

 

[alex456123]

You can't fix the ticking. Just a warrior trait. I suggest adjusting The valve lash, but I will never stop ticking unless you upgrade to HD valve springs and a bigger cam.

 

[bwatson]

Stator wiring Issue for Yamaha 1987 warrior 350

Got everything working... new stator was the key. But for some reason.... the battery is not charging enough after running the quad for an hour or more. It attempts to start but doesn't have the amps.

If I hook up the charger for 10 minutes at 2 amp 12 volt's..... she will turn over really fast for a bit but may or may not start up. If I attempt to charge the battery more..... it doesn't seem to charge it any more than it originally was.

The new stator wires were green and brown and a 3prong clip. I connected the green wire to the red wire and the browns together. Is that correct?

Any help would be greatly appreciate.

 

[fishx65]

I see you replaced the ignition coil and then the stator. Was a bad stator the reason it would run fine for a while until it heated up?????

 

[bwatson]

A few parts...

Hey there.... The issue was with the Ignition coil itself first. I did change the Stator (Caltric)... and battery started charging up again but not a lot.

Found out that the Front engine mount was broken... and someone suggested that it could lead to a bad grounding problem. Still waiting for parts.

The fact that the main negative cable going to the engine block for ground is heating up.... or the smaller wire that is going from negative battery terminal to frame is heating up is that there is a bad ground.

The battery is fine and maybe overcharging....that's why the wires are getting heated... no ground.

So... ordered new front engine mounts and got a new 10 gauge wired to ground out the system to frame. If this doesn't work.... the next thing suggested by a great source was to change the Regulator/Rectifier. 30.00 at Caltric.

Thanks for replying!