Hello all, I have what I believe is a 2000 polaris xpedition 425 that has been sitting up for a while. I took the carb apart and cleaned it, checked the fuel pump and all the hoses and replaced the spark plug. Finally got it to run again and it idles fine. When I quickly tap the accelerator or get it above 1/2 throttle in neutral it will bog down. It will drive very slowly in 1st gear unless I come to the slightest of hills and I run into the same bogging down issue. What could be my problem? Thanks in advance for any help/advice!

 

First thing I'd do is check valve clearance(.006 intake and exhaust) and check the exhaust cam lobe for wear like this one.Bad Cam Pic - ATVConnection.com ATV Enthusiast Community The Expedition 425 shared the same cam as the Magnum 425 and Sportsman 500 of that year model and many had wear problems that caused symptoms like what you're experiencing,would idle good but bog down or backfire under a load. May or may not be the problem but I'd rule that out first. Plus if you don't have the air box and filter back on that could be another reason as they won't run worth a flip with out it.