Hey guys/gals,

Haven't been on the site for a while as my projects have been on a long term hold due to lack of funds. Well, things are looking better in that department so I started messing with the 1990 Trail Boss 350L (W908139) again. I left off trying to get the brakes functioning again. Weird thing. I crank it up, drive it into the garage. Started working the brakes again. Finally got leaks fixed and a good master cylinder and brakes are good to go. Also the AGM battery decided to just up and quit (open cell). Fixed that too. So, after owning this project for nearly 2 years, I finally have every single thing working @ 100%....or so I thought.

Now, here's the weird. I crank it up with no issues, put it in reverse to back out of the garage, give it some throttle, it starts smoking heavily and acts like the brakes are stuck or something is preventing it from moving. Put it in H and L = same result. Within 2 minutes, I blow the head gasket. I thought, well, all I messed with was brakes, so I put it in Neutral and can push it freely back and forth, so brakes are not locked up. So, back into the garage it went. I replaced the head gasket, flushed and filled the system and other fluids. I still have the same issue.--> Just acts like I have a chock under the wheel or holding the brakes on when trying to go Fwd or Rev.

What could this be? Like I said, when I pulled it into the garage to start working on it it was running fine. I've probably put about 40 hrs on it since doing a full top end rebuild over a year ago. All I did was change the battery and replace the brake master cylinder and do a fill & bleed.

Anyone else have a similar issue? I've read and read over the forum as well as the Polaris specific forum.


Stumped?!?!

Dagnabit, I recently picked up a 1997 Sportsman 400L project I wanted to get started on!

 

First off always open the 10mm bleed bolt on the head to remove any air pockets after a head gasket replacement or it can overheat quickly and blow another head gasket or worse.Also sounds like what a reverse limiter can do when it goes out and starts limiting in forward range. Pull the black wire from it and see if this solves the problem.Doesn't sound like brake related if you can push it fine in neutral.If this doesn't help,then could be a problem in the clutches.

 

Thanks OPT. I did make sure to bleed the head for air pockets (call it a hard lesson from the first time I worked on this Polaris). I didn't think about the rev limiter. Would another way to test it be to use the override switch? That is a new switch so I know it functions as it should. Will probably be the weekend before I can get to it but I'll update as soon as I test that out.

 

If pulling the limiter wire doesn't help and you've eliminated any clutch/belt problem. Eliminating the over ride may help,but first things first,defeat the limiter module.

 

If it is anything like my 92 TB the rear brake is on the gear box not the chain. Once you put it in neutral the brake no longer does anything. If the rear brake is a touch rusty and stuck it will still roll fine in neutral but act like it is locked up once in gear.

 

Sorry for the delay in responding. Been a terrible couple of weeks of everyone in the house being sick once after another and crappy weather to boot.

I finally got to messing with the '90 Trail Boss. I disconnected the black lead for the Rev limiter from the terminal board and rode it around a few minutes. Everything seems okay. I connected the black lead back and rode around again for a few minutes and again, everything seemed fine. So, it has been sitting for a couple week covered, but outdoors. I am in the process of installing a Water temp gauge. Once I get all that done I'll give it some more running around and see what happens.

James, you are correct there, the 90 & 92. (in fact all Polaris ATV's I've touched - nothing newer than 1997) have the same rear brake set up. I did a rebuild on the caliber several months ago, but it had been sitting outdoors for some time. Suppose it could have contributed since I finally go a good master cylinder and put brake pressure on it...maybe it got a little stuck. Who knows. Only time will tell now.

I'll update if the problem returns and what I found if it does.

 

If mine I'd leave the black wire from the limiter off as they all eventually fail. I've had some to where you always had to push the over ride before you could even place in reverse with out dying,some you had to have the button pushed to even back up at all and also a bunch that affected even forward range by limiting rpm when they failed. Just a stupid safety device that causes problems when they screw up. Don't think any other atv but Polaris has this set up.

 

Yeah, come to think of it, I can't think of any other brand ATV that has anything like that. I was looking over the diagram for the Rev Override Switch and Rev Limiter. Do you foresee any issue if I simply disconnected those completely from the terminal board? I understand pulling the black ground will eliminate the function, but figure, hell, might as well pull the switch and rev limiter out altogether if I can. Tracing the wires out on the diagram, I don't think completely removing them would cause an issue,

Thoughts?

 

Defeating the limiter isn't a problem and you can leave it that way. The over ride switch does still have to be pushed on most machines to be able to have awd along with full power that you now have in reverse by defeating the limiter. If you don't need awd,just full power in reverse, you don't have to push the over ride. To eliminate even having to push the button at all even for awd some have defeated it this way. Pre 2003 and almost all models that do NOT have the combined override/speedo function button.

Trace wires from the override button (gray/white & gray/orange) Cut the gray/orange and tape up both ends. Cut the gray/white and tape up the end which goes to the override button. Connect the other end of the gray/white to the red/white (ignition supplied 12v) You will also need to trace the purple wire which comes from the handlebars and simply cut and tape both ends.

 

I can't remember for certain if that was done on this quad when I picked it up. I do remember the override switch wires being cut and taped together, but I put it back with a new switch because the way whoever had it wired up, the Rev & 4x4 lights would stay on all the time. They may have attempted to rig the switch circuit and just not done it right. I'll give it a shot and see what it does. No need for an extra switch if I can get around it. If it works, I'll do the same to the 97 Sportsman I'm also trying to revive (waiting on a few parts on that one.

Thanks for the "How To" OPT