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Give me valve advice (2012 kx250f)

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So I checked my valves when I first got my '12 with about 20 hours on it. Intakes were at .18 and .16 Exhaust both at .26... Not trusting myself and my feelers I decided to keep an eye on my valves and put it off for 25 hours. The bikes now showing intakes at .19 and .14 and exhausts at .28, so they've barely moved, and it appears that the exhausts have loosened !

 

So here comes the issue. Clearly the exhausts are out of spec by .06mm, and my intakes  may have moved. How much can I trust my feelers though ? Im curious as to if my exhausts have moved at all and just temperature difference is showing me that .02 difference. I feel like I should shim them, but part of me wants to run it for another ten hours and check again. I race junior class and run the bike pretty hard, change the oil every five hours and air filter every ride. Bike starts two kicks at the most hot or cold, usually two cold, one hot. I was thinking my valves should be tightening up too, yet Im watching the exhausts loosen. What would you guys do here ? Thanks !!

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You should come up with a more consistent was of checking them. You should also invest in a new set of feeler gauges if you are not confident in the quality. Each time you check the valves it should be the same conditions. Its best and correct to test them ice cold. I personally have not seen valves loosen up on the 4 bikes I have been maintaining over the last 2 years. The exhaust valves have moved very little if any at all. Its really just the 1 intake valve that likes to move and start its path of destruction into the head. 

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Valves loosen because of carbon build up.  I agree with Taco's other points.  You have nothing to worry about until you service the top end or sense a performance issue.  When you do clean the valves and seats, Simple Green is the very best for carbon.  No abrasives on the valves!  

 

Check back when you do the maintenance, but for now, race!

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