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Discussion Starter #1
I have about 1500 mi on my machine and it haves a problem with idle when cold. it runs good warm but can be hard starting when its cold and wants to die. if you start it and give it some gas to get it moving and not let up on the gas it will run fine. let up on the gas and it will die. be hard to start but if ypu let it warm up for a long tome it will be ok. anyone ever have that problem??
 

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Discussion Starter #5
Yup, valve was too tight. How does a valve get too tight with 1500 mi on it?��
 

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It may have been set on the tight side upon assembly and as the motor breaks-in they become even tighter. This can be due to the valve coating wearing off, valve seat wear, cam lobe and bucket wear (assuming it's a shim/bucket style setup) and this wear really accelerates if dirt gets passed the filter.

My experience with these shim/bucket 4 strokes has been the valves need to be reset after break-in (20hrs or so) and then they tend to stay in spec for a long time. Polaris doesn't want liability issues, so they probably set the valves right in the middle of the spec upon assembly, which doesn't leave much wiggle room when things wear in and the valves tighten up.

I bought a 2018 Kawasaki 140G dirt bike for my son last year and around 20hrs run time it starts to act up and wouldn't run under half throttle.....in the middle of the St Joe NF about 20 miles from the truck. I assumed the pilot jet had simply backed out, but I pulled the carb and all was well. We limped it back to the truck (ride uphill, coast downhills), took it home and it turned out the exhaust valve had tightened beyond spec.

This is a good reminder that I need to check the valves on my 2018 500. It's nearing 30hrs, so it's ready for a valve check.
 
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