larger exhust valve what gives

[fomospede]

what is needed to run 1mm larger valves?
seat replacement needed?

[JH Racing]

The seats just have to cut. But on 04-05 most builders including myself will change guides to be able to use the CRF ex valves they are a 5.0 stem. The 06+ head already use a 5.0 stem

[fomospede]

are there honda valves available in +1mm
possibly from a crf or something

[CJM]

Originally posted by fomospede
are there honda valves available in +1mm
possibly from a crf or something

nope.

Ferrea (sp) valves, kibblewhites tend to snap..

[fmfhonda250r]

I like a ferrea valves in a 5.5 less prone to breaking a ex valve. Broke a crf valve,kibble white and a faction all using the 5.0 stem size since switching back to the bigger stem i have not had a issue. Just my findings on my mx motors.

[JH Racing]

02-03 CRF are 31mm ex which is +1

[simon7]

CV4 is making their own stainless valves. Same cut as their ti valves they come in +1 +2 real nice valves for the money.

[hondathumper92]

Does the crf exh work pretty good on the 06 and up heads and how do they hold up

[fomospede]

Originally posted by CJM
nope.

Ferrea (sp) valves, kibblewhites tend to snap..


so do you run there springs and retainers as well?

[CJM]

Originally posted by fomospede
so do you run there springs and retainers as well?

Nope. I prefer stock springs in most cases. Are aftermarket springs nice-sure but I dont think they gain you anything but the name.

[fomospede]

are the ferrea valves the same weight as stockers?
theres no issue with floating valves ?
im running a HC2 cam?

[ds268]

In any case where new, high quality valves are used I always recommend updating the springs. Factory springs will fatigue over time and when you add a heavier valve to the mix, it's a matter of time. Even aftermarket springs will fatigue over time. To me, valves are half the equation unless you're sticking with factory valves on a honda cam which there is nothing wrong with!