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Discussion Starter #1 (Edited)
2009 Polaris Sportsman 500 ho. Putting around the yard and all of the sudden, started to make a valve racket. only 150hrs on the machine, i am to only owner. Popped off the valve cover, and the intake valves are slightly out of sync. Will adjust to the 0.006". My question is, there seems to bee slop in the rocker arms side to side on the rocker arm shaft, almost .125" is this normal? Haven't removed the cam yet, seems to be a click (possibly the cause of the noise i hear) right after t.d.c. the exhaust valves move (open) slightly when i hear this click. If this is the compression relief, What can i do to check if everything is functioning correctly?

Just a little more info:

Engine runs fine (just noisy head/valves), seems to not effect performance (didn't rod on it with the valve noise) starts up just as usual (4-5 cranks cold - in single digit weather). What i can't figure out, why would this happen all of the sudden. I can see if the valves are out of sync this would cause valve noise on compression/power stoke. Everything on the valve set screws seems tight. I realize it could have moved all of the sudden and then now appears tight. It was due for an oil change, changed oil, oil seemed to have a bit of a gassy smell, not bad, like bad rings (blow by), air filter was damp, could be just condensation, but a bit gassy smell.

Without taking out the cam, everything seems like it is functioning correctly. No visual wear, or feeling any wear on the cam or the rocker arms, valve springs appear fine, cam slides are pristine, cam chain is tight, etc.

Any suggestions would be greatly appreciated.
 

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I believe Polaris recommends valve adjustment at or around 100hrs. My 500 is a little loud in those start-up temps too until it warms up. Then it sounds normal ( a little valve clatter seems normal for these machines ).
 

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I believe Polaris recommends valve adjustment at or around 100hrs. My 500 is a little loud in those start-up temps too until it warms up. Then it sounds normal ( a little valve clatter seems normal for these machines ).
Are you sure it isn't 1K hours like the 550?
 

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Welcome to the board!
 

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Discussion Starter #6
Anyone know what the tolerance of the rocker arms parallel to the cam (play) should be? To me they really seem sloppy almost 0.125" side to side. This is even after the valves/rocker arm setscrews are adjusted.

Unclkato - The ATV was warm when the sudden noise change happened. Was doing chores 20-30 minutes, idling, start, stop, seemed to be running fine (normal) then i was going across the yard, 15-20 mph and the valve noise started. I let off the throttle and coasted to the shop. I first thought i blew/bent a valve. Shut down the ATV and pushed it in the door. Pulled the spark plug wire and bumped the starter to make sure it wasn't a starter issue (engage/disengage), turned over fine. Then ran the starter to see if everything turned over fine and it did. So I started up the ATV and it ran, just with this new valve noise.

My cousin listened to the ATV run and thought it could be a valve issue. (Auto Mechanic by trade). So we pulled the valve cover off and noticed the intake valves were slightly out of sync. About 0.004" difference on first measurement, then according to the cam, at TDC, about 0.003" difference between the intake valves. Exhaust valves seem fine at 0.006"

According to the service manual, there is supposed to be a timing inspection plug/hole somewhere near the rope stater to determine TDC. I assume its a mark on the flywheel, but the 09 doesn't have a rope starter, and i can not find any inspection plug anywhere near the crank/flywheel. Do i have to pull the engine/flywheel cover completely off to see this mark, or to determine the crank position. I just want to make absolutely sure the cam and the crank are in sync. I know the ATV probably would run if they weren't, but my time is cheaper than an engine rebuild so I want to check it out to cover my bases, especially with the plastic off now.

Any additional knowledge in this area would be helpful before i have the entire bench covered with unnecessarily removed parts. Sure makes working on the ATV easy though.

(Also finally getting around to installing the winch I've had in a box for the last 2 years, picked up a 2500lb Polaris brand winch used on ebay for $35 and about the same for shipping, could use a new cable and probably a hook too.)
 

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Yea it sucks that Polaris got rid of the pull start in '09. My 500 hasn't hit the 100hrs mark yet. I did pull the pull start housing when I replaced the stator but didn't notice where TDC was. In the vid he said if you don't hear valve noise ( or no noise ) is not good. I think that's why these engines have a little valve clatter. They have a "Harley" vibration to them which on this forum seems to be normal. I would say adjust the rest of the valves to spec and go from there. If the engine runs as should, deal with the clatter like the rest of us.
 
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