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What would be the advantage of converting to the "skinny" valve stems and "beehive" springs?


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DOPE
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skinny valve stems obscure less of the port.

beehives are said to hold tension longer and have less weight up at the collars. i have a head with beehives but i havent run it enough to have a valid opinion


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What Kev said.
I have that setup on my 650 race bike. 3rd season on them. Had a bad initial experience where a valve contacted a piston at speed. Didn’t end well. We upped the spring pressure to about 90 lbs and it’s been good since. Also increased v/p clearance from .060 to .090. Does it make more power than stock? Probably a little.

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My double engine Triumph has beehive springs and 6mm intakes….Supposedly the beehive also offers better valve control with less pressure…Set up at 85 pounds closed and 205 at .415 valve lift, engines have seen 7200 rpm…But Mike had a difference experience….I do know that the 6mm intakes bend like they are made from wax from contact with the TDC stop tool…ouch…
For a street engine? Probably no advantage…


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