I do understand this is more of a Quad form but from what I understand the 500 engine has been in use for some years and in different platforms.
I have a 2005 polaris ranger with about 8XX hours on it. it was purchased from the original owners who only used it around their house and at their hunting club. about a month ago I was out in the forest doing some fairly hard riding when it developed a knock.
I tore down the engine, and didn't find anything too concerning besides on the balance shaft and oil pump a tooth or 2 had some slight chipping.
I replaced OEM crank, OEM balance shaft, OEM oil pump, all with OEM bearings. a "niche" cylinder kit, a new bendix, and bendix bushings. I lapped the valves exhaust valves looked fine, intake valves had a small burr around them. and the exhaust rocker has a gouge on it from the decompression ball.
now I did reuse the timing chain, timing sprockets, head, cam, rockers.
there is no clutch on the engine right now so that can be eliminated. the timing chain has a little less than a 1/4" of slack in it on the side that doesn't have the tensioner. I can not see any flopping around with the side cover off and the engine running. the valves are also correctly adjusted.
i'm completely lost at what else could be causing this noise. I understand that these 500's are just noisy engines, but this doesn't seem like a "normal" noise.
link to video of the knock-
the smoke in the video is from oil that spilled on the manifold from running it without the valve cover on it.
any info or possible things to look for would be greatly appreciated!!!