After reading the dirt rider valve trains articles i was wondering how much performance you would lose by getting the kibblewhite stainless steel valves? I think the reliability of them would be worth every penny but don't want to lose any performance.
Posted by: Rich Rohrich---------------------
None of the dyno tests we've seen on the YZF250s showed any loss of power by switching from titanium to stainless steel valves. You can count on the fact that a titanium valve that isn't sealing properly will cost you more power than any spring pressure difference ever could.
Posted by: chopair---------------------
Rich,
One of the local "naysayers" is So Cal is spuing the the "fact" that the increased spring pressures (from KW installations) just wears on the cam lobes instead of the valves seat. Have you seen any evidence of that?
Thanks,
RH
Posted by: Rich Rohrich---------------------
It's actually the other way around. Inadequate spring pressure allows the buckets to bounce during the closing phase and allows the bucket to loft over the nose and come crashing back down on the backside of the ramp. Both cause excessive wear. I've posted a few pics on this type of wear in the forums but I'll add them to this thread when I get home from work tonight.
