Yamaha ATV's with 4wd problems look here! Cheap fix!
 

Long time reader first time poster. Figured I would contribute a little to the site as it's helped me out alot just reading on here.

Yamaha atvs tend to have alot of problems with the 4wd servos, at least mine do, especially once they are put under mud and water time after time. Yamaha wants to sell you the complete unit for $300+ once it goes out. I've found a solution for a quarter of what the dealer wants.

I have found a servo (motor only) replacement meaning the small motor inside of the black servo case. It runs the whole 4wd/difflock/2wd operation and is the only part in these servos that go bad unless of course you break the case somehow.

These motors will fit the following Yamaha models.

08-11 Rhino 700
06-09 Rhino 660
06-09 Rhino 450
02-08 Grizzly 660
07-11 450 Grizzly
09-11 Grizzly 550
03-06 Kodiak 450
07-11 Grizzly 700
08-11 Grizzly 450
07-11 Big Bear 400
04-06 Bruin 350
04-06 Kodiak 400
05-06 Big Bear 400
06-10 Wolverine 450
07-11 Grizzly 350
07-08 Grizzly 400

I did complete write up on taking the servo off and installing one of the motors. So here it is.

This was on an 05 Grizzly. They are all basically the same. Only difference is on some of the newer models there is a gear on the small motor instead of the collar you see here.

Also, I pulled the complete diff out due to having to change a seal but you can do this with it still in the bike. It upside down in the first picture but you get it.

If you have a skid plate on you will have to remove it to access the bottom bolt on the servo. I also recommend having the bike in 2wd to ease in installing the servo back on the diff.

Remove the 3 bolts that hold the servo on the diff. Gear oil is going to pour out unless you drain it first.

http://i80.photobucket.com/albums/j1...2/IMG_0946.jpg

Once removed from the diff. Remove the six T-25 tamper resistant tq screws that hold the servo together.

http://i80.photobucket.com/albums/j1...psb00ab1bc.jpg


Once you get the screws out, carefully pry the servo apart taking extra care not to turn the gears inside. If you turn the big black plastic gear, you will get the unit out of sync and cause yourself problems when you put it back together.

Once apart it will look like this.

http://i80.photobucket.com/albums/j1...ps9b0098bf.jpg


You can see the two screws that hold the little motor in.

http://i80.photobucket.com/albums/j1...ps11adc7b2.jpg


Remove those two screws and carefully pry up on the motor and remove it and the worm gear attached to the end of it.

Picture of the motor removed.

http://i80.photobucket.com/albums/j1...ps48a177ac.jpg


Once removed, put your new motor in and enjoy your 4wd again and the money you saved.

Hope this helps someone out. If anyone needs one of the motors just let me know.

Thanks, just bought a 2007 350 Grizzly 4x4 and bookmark this in case the day comes.

No problem, glad to help!

So where to get the motor? Make and part #'s are great info! Is a direct replacement?

ok so I replaced the motor in my unit and there is no marking on the gear to line it up and I had to remove the inside gear to cleanup the old grease it was caked and hard preventing connection . Anyone know how to get everything back in sync ? when I hook it up it goes from 2 wheel to 4 wheel and stops and does not return , does the same thing every time so I am thinking it is not in the right position inside .
Some background ; wiring harness burnt off on exhaust repaired this worked for a day then started blowing fuses put a 10 amp in and fried the motor replaced the motor and now the above problem . going to order new servo unless someone has a solution for this

Jay

You should have a mark on the gear sticking out of the back of the servo case that lines up with a mark or an indention on the back of the case. I'll pm you my number, I can split one apart and take some pictures for you if need be or you can give me a call and I can try and help you out.

Thanks for your good info.

Could you tell me where you got the motor from? It seems like you have to buy the entire servo moto from Yamaha which is over $500. If you have a way to find the motor itself could you please let me know? Thank you.

I have the motors, I sell them on ebay or through PayPal. I sent you a pm with details. Thanks

I still have the motors available if anyone needs one.