Sportsman 400 Electrical Problem

[Gissert]

I have been having some trouble with my 2002 Sportsman 400.

The battery seemed to be getting weak, and it was not starting with the key when colder. I just chalked it up to a battery going bad, but now I think it is something else.

I did a little troubleshooting this morning, and here is what I know so far:

Key off battery voltage is about 10 (Batt is obviously run down)

Starts and runs fine on first second pull with recoil, voltage to the battery is then about 5 volts.

Speedometer and odometer are intermittent. If I switch out of AWD when the spedo is inop, it won't go back into AWD. If the spedo is working, it will then go back into AWD.

Then I ran out of time. I am going to put the battery charger on it and do some troubleshooting later.

If someone out there has experienced a similar problem, I would be very grateful for tips. It is COLD out there today and my garage is unheated.

[Dave]

1st thing to do is make sure the battery is good. Speedo wouldn't work good with a bad battery. Neither will AWD. And, one or two pulls will still start the machine with a dead battery. See what the voltage is after charging the battery and go from there.

[Gissert]

Thanks Dave,

I did charge it up, and the same symptoms remain.

I suppose it could be a bad battery, but there is only about 4.2 volts going back to the battery from the charging system. I'll try and chase down the stator outputs next weekend.

[CHOPPERTHEDOG]

I know that on atleast some motorcycles that the charging system doesn't put out any voltage at idle rpm. I don't know if the same is true for ATV's. In your situation a good service manual may be the answer as they have sections to help diagnose most any problem you might come across. If you have good mechaniccal aptitude I would say get the factory manual.

Good luck

[Gissert]

Thanks Chopper,

I will try and find a service manual someday, LOL.

I checked the voltage at idle, and about half throttle. No change.

I want to check the ac voltage going into the rectifier/regulator vs the dc output. I just flat ran out of time, and it was getting to the point where I want to do this in a heated garage.

[spearchucker]

The battery could be shot and dragging the charging system down. I would test the battery after charging to make sure it holds a charge before you ruin the alternator.

[ChuckN]

Hey Gissert, you want me to run over to your place and test your wheeler to take it to spot X? LOL

Let me remind you that it was -15 that night, and your battery either flat out died or she froze (mine froze perty goot too). It's 40 degrees right now, but it's going to be another deep freeze tonight and rest of week. How's dat?

[GRAND DAD]

Hey Gissert I have a 05 honda 450 and mine was doing the same thing this weekend every time I turned around the battery was dead!and am not to sure what to do about it am thinking its the cold,if not am open for ideas do they sell a cold wether battery!

[Gissert]

ChuckN -

Help yourself, really.

You can get there in 2WD.

It has been exhibiting symptoms for about 6 weeks now. It could easily be as simple as a bad battery. I should have brought it back with to charge and load test. Doh.

Judging from experience, however, it seems a bit more indept that that.

[ChuckN]

"Judging from experience, however, it seems a bit more indepth that that."

I won't even start with the Polaris jokes. LOL

My Honda did not like that cold weather we had at all, weird things happened too. (winch intermittenly did not work, battery would die after engine ran about 2 hours earlier, etc..)

[Gissert]

Pull Off Lake And Repair In Summer, LOL

I've been looking at that diagram that Dave so kindly linked. I am going to check the connections on the voltage regulator input and output. The way the speedo goes intermittent with resultant loss of AWD is causing me to suspect a connector to be loose or corroded.

Excellent diagram Dave, Thanks!

[Gissert]

Well, I finally got my quad fixed. Thanks for all the input.

It was the battery, it appears. Looks like I had a couple of marginal cells. It would hold a charge, but would not hold any load at all. The charging system just could not deliver the current the battery was demanding.

Once I had the old battery out, I could see two of the middle cells looked either dry or frozen.

Put the new battery on, and it fired right up, with the charging system putting about 14 volts back in.

I guess I am so used to chasing wiring problems on aircraft that I defaulted into a wire chasing mode.

Thanks to Dave for the link to the wiring diagrams. I understand the relationship on everything much better now.

Time to fish!

[Dave]

Good job, Gissert! Good Luck fishin'!