ATV Answerman: Stuck in 4x4, Oil-Injection Issues and Locked Brakes

Jul. 29, 2014 By Rick Sosebee, Photo Courtesy of Can-Am

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Locked Up
We bought a Tao 50cc ATV and the rear brakes seem to be locked. Our daughter rode it several times but it has been in storage for a few months. The pedal will move up and down and the fluid is full but the brakes will not stop the wheels. I don’t think the rear caliper is working.

The pedal is most likely connected to a small master cylinder and this would be my first stop when searching for the problem. Braking components, especially cheaper systems, will corrode internally and create many problems. The fluid that is in the cheaper systems can also be a huge part of the problem. As the piston corrodes in the cylinder it can stick in place. Your problem is compounded by the fact that the ATV you have is not even on the “repair parts” radar. There will be some research to be done on your part, but the one glimmer of hope is that you could disassemble the master cylinder and clean out the problem. If you’re not a mechanic then I would suggest a local ATV shop or the nearest scrap yard to find parts.

Locked Up II
I was riding up and down some dunes and all of a sudden the rear wheels locked up and it won't shift. It still runs good but it won't move at all. Please help.

I could really use a little more information on this one, but let me suggest a few things to think about. Take the master link out of the chain, provided it has one, and remove it to see if the rear wheels will turn smoothly. If the rear wheels will not spin then you may have some bad swing arm/axle bearings. If they will turn freely then you can start looking into the transmission. This could get a little more complicated as there could be internal damage. If you are not sure of your mechanical skills then I suggest taking it to the local Polaris dealer for service.

Stuck in 4x4
Why will my 2000 Yamaha Kodiak 400 ATV not come out of 4x4?

Sorry to hear your Yamaha is giving you grief. There are only a couple of things that could have your machine locked into 4X4. The very first thing I would inspect is the electric differential servo on the side of the front differential. This has a few electrical components that can go bad over the years of use and is the cause of problems just like this. By removing the servo motor from the side of the diff you can actually disengage the drive, provided it is not locked up internally. These motors are expensive to replace but there are companies who will repair them for a fraction of the money.

Will it Fit?
Can anyone tell me if the rear differential in a 2005 and a 2002 Arctic Cat 500 4x4 automatic ATV are the same or not? I need to replace the one on my 2002.

These two rear differentials are vastly different and will not interchange. However, there are parts available for both of these rear ends so try to find the broken parts online before ditching the differential.

Scrambled Warrior
Will a Polaris Scrambler gas tank fit on a Warrior?

I am positive that the gas tank off of the Scrambler will not work on the Warrior. Not only would it not fit but the taboo generated by simply placing the two machine parts together would be very ugly.

Mixer Not Mixing
My automatic gas/oil mixture system in my 96 Polaris Xplorer 300 4x4 stopped working. What is the oil to gas mixture for this ATV and how do I fix the automatic system?

When dealing with the life blood of the two-stroke engine it is always best to fix the oil-injection system. But, if you have to mix your own fuel start with a 32:1, as it is probably the safest mix. If the smoke overwhelms you then you might try 40:1 but realize you are putting the piston and cylinder at risk of seizing. Carefully proceed with this advice and know you control the life and death of your machine with this.

KMS Turbo System for Yamaha YFZ450 ATV
How much is the kit I want one?

It would appear that the company KMS Turbo is no longer offering these turbo kits.  If you would like to contact them about the technology and possible leads to an alternate option for your machine, here is the link:

Popping Rhino
My Rhino 660 will pop very loud when I decelerate and it’s getting worse. Where do I start?

I have found that the head pipe on these machines will crack right at the head and create a leak that responds with an ear-shattering pop or backfire. Check here first and if you see black soot on or around the head coming from the header then that could very well be the problem. If everything checks out here then you will need to step back to the “Y” pipe or collector for the header. This is also a place for cracking in the steel pipe itself and possibly the culprit. Other spots of interest could be the doughnut gasket that connects the silencer to the exhaust header. Check it all and then if that is clear of problems maybe a lean condition in the fuel is an issue. Simply closing off part of the air box would be a quick test.

Be sure to keep a check on your fluid levels in the off road beasts you ride this summer. Temps are getting hotter and it could mean the difference between ride or walk! Ride safe and take a child with you!

Have an ATV or side-by-side tech question for the AnswerMan? Send an e-mail with your name, vehicle year, model and a detailed description of the problem to, Attn: ATV AnswerMan.

Previous ATV AnswerMan Columns
June 2014

May 2014

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