Hi all, I am sure some one out here has these answers for me. My in-laws just picked up a used Polaris Magnum 425 4x4. It's been setting for a couple of years. There are a couple of things going on with it. The first question is what exactly does the reverse override do? Second question is what would cause this machine to idle like a dream in reverse but as soon as you put it in neutral or forward the thing won't idle. The idle adjust does not make a diff. in N & F. Your thumb has to be touching the throttle for the thing to idle (except for reverse). Any ideas would be greatly appreciated. One last question, do you need to bleed the read brakes in any special way? The calipar was locked when they got the machine, we blead the line, now the rear brake does not close the calipar. (push brake, hold, crack valve, tighten vlave, repeat a few times) This is what I did to bleed it.

Aside from this we love this beast, we make our own trails with this hog.

Thanks In Advance
Trower

 

The reverse override button allows you to override the rev limiter while in reverse. It also allows 4wd to work while in reverse. Or another way to say it would be that unless you hold the button down, you only have 2wd while in reverse (even when in 4x4 mode) and can't go over about 5 or 6 MPH backwards.
The reason you have to hold the throttle slightly to keep it running is because the throttle cable is too loose. Most Polaris machines (and all the new ones) have what is called an ETC system. Stands for Electronic Throttle Control. This is a safety feature. It is supposed to 'sense' if the throttle cable sticks open, and cuts spark to the engine, to prevent a runaway. It works by sensing the tension in the cable. However, if there is too much slack in the cable, it 'thinks' it is stuck, and will cut the spark, even at idle. It runs in reverse because reverse has it's own rev limiter (controled by the override button). Tighten the throttle cable up some, and I bet you cure that problem.
The rear brake problem is one of 2 things. On the older machines, it was mechanical. To adjust the rear brakes, there was a bolt/locknut arrangement on the caliper. If yours has the mechanical brake, follow the linkage to the caliper. The bolt I am talking about is in the center of the little arm the linkage rod pulls on.
The newer machines have hydraulic rear brakes. These have their own system. The rear brake has it's own reservoir, master cylinder, and even it's own pistons in the rear caliper. Did you bleed both systems (if you have the hydraulic rear brake) There are 2 bleeder screws, one for the hand brake & another for the foot. Also, be sure the master cylinder is full. This would be located above and a little behind the rear pedal. Also, check the pads, as they tend to wear fast. They may need replacing, too.

 

Trower;

The reverse override is a safety feature built into the quad by the manufacturer to prevent somebody from accidentally nailing the throttle with the machine in reverse and loosing control. Normally when the quad is in reverse you have a very limited amount of power when you hit the throttle, but when you press the reverse overide buttom you bypass this safety feature and you then have full power in reverse.
This is all done electronically by a black box or something but I don't know exactly what is affected. i.e. revs limited or timing changed or what.
As far as your idle problem goes have you thoroughly disassembled and cleaned the carburetor. Sitting for long periods can really gum up a carburetor. Also make sure there is no junk in the fuel tank.
I bought a 350L about a year ago and the thing was acting up somewhat like yours. One minute it would run alright and then the next I could not get it to idle at all. I took it into the dealer and he told me it was a bad reverse limit switch or reverse overide switch I don't remember exactly what he called it. If yours has been setting for several years and especially if it was setting outside then you could have some corrosion inside the terminal board that these switches are connected to. Just a thought anyway.
As far as bleeding your brakes goes just 1. put a small polyvinyl hose on your brake bleeder and put the end in a glass jar. 2. Remove the cover off of your master cylinder. 3. Crack open the nut on your brake bleeder. 4. Slowly add small amounts of clean fresh DOT 3 brake fluid while at the same time squeezing the brake lever slowly.
Never let the fluid level in the master cylinder drop too much
5. tighten up brake bleeder nut and remove hose.
6. Make sure master cylinder is nearly full (1/4&quot from top.
Be careful with the brake fluid as it can remove paint and decals from your quad if you spill some on it.
I don't think the rear brakes are adjustable as far as the hydraulic system goes, but they can be adjusted for the mechanical (foot lever) emergency brakes. In other words adjusting the rear brakes will not affect braking at all when you squeeze the brake lever. But it will affect braking when you step on the emergency foot brake.


Hope I helped you some
Doug