Doc's Anything Goes
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Say no to scooter abuse
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Post by jct842 on Feb 28, 2012 11:01:58 GMT -6
Most people attribute the frequent valve adjustments that become less and less to the head work hardening. Has any one considered that the valve springs are getting weaker and in so do not hit the head on the rebound as hard?
I wonder if you could accept a slightly less max rpm that you could replace the springs with better quality ones that did not have the strength and there fore would hit the valve into the head as hard.
All that is really nesc. is that the valve seal. if it floats at 10,000 I sure don't care, infact I could very easy accept 7500 rpm as the top speed, and possibly less too. I am thinking the chinese have put a much stronger valve spring in that gets weak over its life and pounds the valve seats un-nessacarily hard. got to go....late for lunch john
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Scooter Doc
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Post by sprocket on Feb 28, 2012 11:27:39 GMT -6
Valve springs have nothing to do with valve adjustment...also each valve has two springs...inner and outer...
Springs do loose tension over time but not so you would notice...
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Post by kz1000st on Feb 28, 2012 13:01:15 GMT -6
The valve stems stretch during the break in period. Also the head of the valve is spun welded to the stem and weakens metal hardness. I have better springs in mine and I still have to adjust them annually-so far.
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Post by Alleyoop on Feb 28, 2012 14:08:39 GMT -6
What johns theory is to have weaker springs so that they do not snap back hard onto the head and either make the valve head thinner and or the head valve depress causeing your tight valves. But like he said weaker springs might cause the valves to float at high rpms and he is willing to take lower rpms without valve float in order not to be having to adjust the valves so often. Alleyoop
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Scooter Doc
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Post by sprocket on Feb 28, 2012 18:11:16 GMT -6
This is common on aluminum head engines, not just GY6s. The valves and seats push into the head... the gaps close
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