Hi there;

I'm working on a '97 polaris xplorer 500 and it is having an issue with fuel or vacumn, I don't know which. ( maybe I'm wrong ) To describe, basically it will start with the touch of a button run at idle just fine. Bump the throttle and it will not get over 2000 rpm ( guessing ), bogs down spits abit and will die. Take the air box out and it runs fantastic. ( slight jetting issues with weather. squirt bottle some fuel into the carb and it will take off ) However, after installing the airbox ( no filter ) it runs the same as if the filter was installed. I have replaced the vacumn slide and the fuel pump diaphrams. VERY MINOR IMPROVEMENTS. I have also cleaned the carburetor three different times. Now to load test with out the airbox it wil not run normal under load in hi range, in low range it runs much better however it seems to run the carb dry or something cuz it will fall on its face and when the throttle gets released it wil stay running and when goosed immediately after it runs good again. New plug and fuel filter also. Compression is at 120 PSI.

The part that gets me is how can it run good with out the air box in then take such a dump when the box is installed with NO air filter.



Thanks for any input



Clint

 

i aint to sure but try to run some seafoam through the stuff works magic

 

it sound like its way to rich, which is why it bogs out, removing the air box allows more air to balance the amount of fuel & air

 

that's what I thought, then, for verification, I squirt fuel into the intake track and It improved tremendously. ( like normal )

 

i have heard of an issue that there is supposed to be some kind of wire spreader in the intake boot of the airbox and if its not there when you try to rev it and causes a vacuum in the airbox then the intake boot will try to colapse on itself causing the air to not get thru. dont know if it applies to your bike or not but could atleast give you somewhere to start.

 

the intake tract is a hard plastic.

 

Maybe this is a little too obvious, but are you sure the airbox is not hitting something (not sure what, maybe throttle cable or vaccum hose or shorting a wire or something) that would cause this? I agree that the airbox with no filter shouldn't make much difference than no airbox at all, unless it is interfereing with something mechanical. It there clearance all around the airbox, with nothing hitting it or getting pinched?

 

I've concluded that it HAS to be a vacumn issue creating a fuel flow problem. By adding the airbox the immediate volume of air is reduced hence changing the vacumn pulse. I'm having the carb chemically cleaned, and while that is out I am going to look at the valve train just to rule out that issue. I believe that it runs too good with out the 'box for this to be a problem. And I just found out that this thing has set for the last 2 years. The guy said that his wife and daughter rode it. It must have been the first day he got it. That's the issues one deals with when not dealing with ones own toys. A dealer near me has a sign posted at teh parts counter that states; " THE WRONG INFORMATION WILL GET YOU THE WRONG PART EVERY TIME. "

 

PROBLEM SOLVED!!!!

For whatever reason it was just the jetting. I ended up at the needle 1 pos lower ( raising the clip ) and 5 sizes on the main jet. It runs fantastic!

Hope everyone has thirs running also.



Clint