These are pictures taken last night on stock Teryx that I borrowed to use for the installation procedures. This unit has 43.6 hours (who knows how accurate that is!!) and 497 miles on the display.
When I removed the center console the first thing I noticed is that the plenum was already starting to slide off the carbs and was leaking oil. If oil can get out then DIRT can definately get in.
This is the picture taken after removing the covers and before removing the plenum. You will see that the plenum is not seated in the boots. There is also plenty of dirt and oil build up.
This is the build up of dirt on the inner edge of the velocity stack that is built into the stock boot. This is the leading edge into your carburetor and should be SUPER CLEAN. This Teryx is probably on the extreme side.....BUT I DON'T DOUBT THAT THERE ARE MORE LIKE THIS ONE.
If you have not already checked your plenum PLEASE DO. It takes about 15 to 20 minutes.....add more time if you find it needs to be cleaned. Don't just look at it though, take it completely off the machine and inspect it to see what is inside. When reinstalling the plenum make sure not to over tighten the hose clamps on the bottom of the plenum as you will make the problem worse. The Aluminum sleeves that I am selling were designed not to crush when tightening the hose clamp and give a better clamping surface so this does not happen again.