over the weekend my buddies and i went to an offroad park. We were all doing some heavy mud riding. One of my buddies started having trouble with his quad. It is an 05 sportsman 700 efi. it has an aftermarket exhaust and a filter kit but thats the extent of the mods. The problem is that it started making a nocking noise on the right side. We were all thinking the worst like it was a rod.The odd thing was that when we got it back to the truck it didn't do it till it got to opperating temp. any one have a clue what it could be becuase i'm stumped.

 

any chance of water injestion?
Check all fluids and the oil to see if its milky.

 

does the noise stay the same or change pitch when you rev it?

 

no water got into air box or motor. oil looks perfect. the noise do get a little louder under reving.

 

lifters may be sticking a little bit, causing excessive valve clearance, what kind of oil are you using? Running something besides polaris oil seems to cause the lifters to stick a little bit i've found

 

I had exactly the same problem. Bent push rod. The POLARIS twin liberty engines don't age well. This is another common Polaris problem.Two thousand dollars later it runs like a top I guess.I traded it. I'm done with POLARIS. Bought a 2008 Grizzly SE.Still getting use to hearing no clunks, rattles and vibrations. Jamie