MY 400 XPLORER RUNS FINE FOR HOURS UNTIL I GIVE IT FULL THROTTLE. WHEN I FULL THROTTLE IT , IT STARTS TO MISFIRE BAD, WITH NO POWER, AT THAT POINT IT WILL NOT CLEAR UP NO MATTER HOW MUCH THROTTLE YOU GIVE IT. IT RUNS PERFECT UNTIL YOU FULL THROTTLE IT ONE TIME. WHEN IT FIRST DONE THIS YOU COULD LET IT SIT OR COME BACK THE NEXT DAY AND IT WOULD BE FINE UNTIL YOU OPEN UP THE THROTTLE AGAIN. NOW IT WILL NOT FIRE AT ALL. HAS ANYONE SEEN THIS BEFORE OR HAVE ANY SUGGESTIONS ON ANY TESTS TO RUN. ANY HELP WILL BE GREATLY APPRECIATED. THANKS A MILLION.  

this happen to my friends trail blazer you clean the air filter and change the spark plug if that dont work take the crb. apart and clean it  

I APPRECIATE THE INFO,  I HAVE ALREADY TRIED ALL OF THOSE THINGS BUT I HAVE NO SPARK FROM THE COIL WIRE. I HAVE CHECKED THE COIL, REPLACED THE CDI AND CHECKED ALL THE WIRING. I CANT FIGURE THIS THING OUT. THANKS FOR THE IMPUT.  

it sounds like the stator is going out.

pull the cover and tghe flywheel and inspect the stator and magneto for dirt, rust etc...

polaris designed these to allow dirt and water into the stator cover. (very poorly designed)

if you find rust and or dirt clean them off carefully, and see if it fires after that.
if not then the stator is most likely bad.  

THANKS, THATS ACTUALLY WHAT IM CHECKING NOW. THE STATOR AND PICK-UP LOOK BRAND NEW AND WINDING IS TIGHT. THERE IS A SMALL AMOUNT OF GREASE ON THE PICK-UP CONTACT. I GOT IN THROUGH THE STARTER HOUSING. IM THINKING ABOUT CLEANING IT OFF AND TRYING THAT, BUT I WISH THERE WAS SOME WAY TO DO A TEST ON IT BEFORE I PUT IT ALL BACK TOGETHER. IVE ALREADY CHECKED THE WIRES TO SEE IF THEY WERE GROUNDED AND THEY SEEMED TO BE IN SPECS.  

no rust on the magneto contacts or the pick up plate?

also check to see it plate may have shifted.
some stator plates are adjustable and if the plate moves it could retard or advance the timing out of it's paremeters.


also did you buy this machie new?

if so it could just need the fuel/air mixture screw adjusted on the carburetor.

as the rings wear in and get weaker you need a different cfm on the carb sometimes to keep it running in top shape.  

I had the full throttle problem on 97 400 sport a full year ago.  It would run great until it was WOT.  I thorougly cleaned the inside carburator bowl and found FORIEGN contaminants inside.  This cleared it up.  However the no spark condition did not happen to me until later in the year.  Sometimes it would start and sometimes not.  Did you ever get your problem fixed?  Jim  

I had a 99 400 xplore with the same issue at full throttle it ended up being the boot between the carb and motor had a crack in it and it was sucking drit change the tube and cleaned the bowl and it was find for a month theb it started all over again to it quick 15 miles back in the woods freind tow me out and we played for a week trying to fuigure it out the took to the dealer they said it was the over ride module on the bulk head and changed out got the machine back and it was good after that