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crf 450 valves? i heard this.....
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Posted by: kamchuka---------------------

some dudes are replaceing them with xr valves or something like that, to provide longer life. does anyone know anything about this? and if so what types of valves would be best? or should i just go back to oem after valve job

Posted by: Ol'89r---------------------

Quote:

Originally Posted by kamchuka

if so what types of valves would be best? or should i just go back to oem after valve job

For longevity I would go with the Kibblewhite stainless valves.

Just my $ .02

Posted by: ProMed---------------------

It is odd how everyone on this board praises Kibblewhite and everyone on thumpertalk only speak of Ferrea. Could it be because Eric Gorr sponsors this board and Ron Hamp sponsors the other?

I have no idea which brand I will go with for my 05 CRF450, but I will buy a new oem 06 head ($220) which has the updated valve seat material.

Posted by: Ol'89r---------------------

Quote:

Originally Posted by ProMed

It is odd how everyone on this board praises Kibblewhite and everyone on thumpertalk only speak of Ferrea. Could it be because Eric Gorr sponsors this board and Ron Hamp sponsors the other?

.

ProMed.

Could be because some of us do this type of work and have had experience with Kibblewhite valves. I have never used Ferrea, but have used Kibblewhite valves in many heads with much success. Has nothing to do with who sponsors what site. Also, Eric does not make the Kibblewhite valves although SFO, a member of this site used to work for Kibblewhite and introduced many of us to those valves.

Just my $ .02

Posted by: Rich Rohrich---------------------

Eric is just a Kibblewhite customer, just like he is a an Xceledyne customer. There is nothing wrong with Ferrea valves, they are well made and of consistent quality. The issue comes with SPRINGS. Ferrea does not supply a full kit with correct springs and proper upper retainers, so you are forced to rely on someone else to engineer a proper spring package, which frankly is a whole lot tougher than making a valve.

. The results people have relying on this approach vary widely. Many folks just buy a generic kit from R&D, but speaking from personal experience I wouldn't put R&D springs in a lawnmower let alone an 11,000 rpm race engine.

Kibblewhite's biggest advantage for most people is they provide a complete kit as an engineered package not a piecemeal collection of parts. Ron Hamp provides something similar using ferrea valves and a spring package he helped develop.

Posted by: kamchuka---------------------

Quote:

Originally Posted by ProMed

It is odd how everyone on this board praises Kibblewhite and everyone on thumpertalk only speak of Ferrea. Could it be because Eric Gorr sponsors this board and Ron Hamp sponsors the other?

I have no idea which brand I will go with for my 05 CRF450, but I will buy a new oem 06 head ($220) which has the updated valve seat material.

so the 06 heads are better and worth the doe?

Posted by: SFO---------------------

I'd love to see a mx shootout, RH built cr-f vs. EG built cr-f.
I'd like to see how much it costs to keep each one going a season as well as their relative performance. Not some socal mag shootout, a normal a level weekend warrior.
Have it be hosted by an independent websight so no affiliation concerns.
Justa thought.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by kamchuka

so the 06 heads are better and worth the doe?

There is no field evidence that the wear rates on the 2006 heads are any different than the previous years, 450 & 250s included. What you might find is the exhaust valve guides are a bit softer in the new heads and wear the bottom third portion (nearest the seat) a lot faster than the earlier models.

There is nothing wrong with the 2006 head, just don't expect some huge change in OEM valve life as a result of switching.

Posted by: ProMed---------------------

Quote:

Originally Posted by Rich Rohrich

Good info thanks. Sounds like Honda's "improved valve seat material" claim may be similar to BNG?

Posted by: Britt Boyette---------------------

Do the 06 450R heads flow any better than my 03 450Rs head? This is the type of gain I would be after.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by Britt Boyette

Do the 06 450R heads flow any better than my 03 450Rs head?

If you are looking for an airflow gain on the CRF450 that will translate to something useful you'll need to have the valve seats and port throat modified regardless of the year. Swapping stock heads won't accomplish it.

Posted by: rick#3---------------------

Hi Rich,
This is getting of the subject but I was wondering what your opinion is of the currently cylinder heads available from the different manufacturers.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by rick#3

Hi Rich,
This is getting of the subject but I was wondering what your opinion is of the currently cylinder heads available from the different manufacturers.

What specific info are you looking for?

Posted by: rick#3---------------------

What design you feel is best performance and reliability and does any one brand have more potential then the other.

Thanks

Posted by: Rich Rohrich---------------------

***** WARNING The following are MY opinions based on MY experience modfying and rebuilding these engines over the last few years. Everyone is free to disagree with my assessments.

In terms of reliability the Yamaha both 250 & 4xx have proven themselves to be pretty bulletproof if the rider pays even basic attention to the service intervals. They are the gold standard for reliability in this arena. They aren't perfect, but anyone with reasonable skills can keep one competitive for a long time with a minimal investment of time and money.

In terms of performance potential the Honda 450 has the best cylinder head, and the best overall engine design IMO. From a 250F performance standpoint I'd say the Yamaha and Honda are fairly equal, but most racers will probably find the Yamaha cheaper to own long term.

The Kaw & Suzuki 250F engines never should have been built IMO (this includes the 2006 models). It's a shame really because it seems like a really nice chassis. The 450s from Kaw & Suzuki have much better engines in terms of reliability but they are nothing special in terms of performance potential. The Suzuki 450s still have odd ball cam dynamics that make them a crap shoot for serious racers, but they seem to be doing well for the average weekend guys. I don't have enough field data on the Kaw 450 to have much of an opinion on it's long term reliability, but it seems to be holding up a bit better than the Suzuki 450 when an expert level guy is riding. My guess is like the Suzuki 450 it will prove to be a good bike overall for the average guy.

If I could have whatever I wanted I'd take the Yamaha 250F engine in the Honda 250F chassis, and I'd take the 2005/2006 CRF450 as is.

I've held on to my 2002 CRF450 that I bought new and have been thrilled with it, and I KNOW how much better the 05/06 version is.

Hopefully this answers your question.

Posted by: XRpredator---------------------

I'd get dimpled chucktanium valves

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by XRpredator

I'd get dimpled chucktanium valves

.... to match the dimpled Chucktanium plate in his head.

Posted by: rick#3---------------------

Thanks Rich, What are you thoughts on the new KTM 250SXF?

Posted by: Rich Rohrich---------------------

I haven't taken one apart so I'll pass on commenting.

Posted by: rick#3---------------------

Thanks again Rich.

Posted by: Vic---------------------

Quote:

Originally Posted by Rich Rohrich

I haven't taken one apart so I'll pass on commenting.

It's a KTM, so no one will ever have to.

Posted by: kamchuka---------------------

Quote:

Originally Posted by Vic

It's a KTM, so no one will ever have to.

haha! aside from that.....thanks you very much for all the advice. ends up, well it was my buddies who bought it right before he left for iraq. never could start it right, so he left it with me, i did all the basics and later discovered the valves where shot. i was going to do them, but we decided to wait, and good thing cuz there doing it for him. WOW! there is still some stand up folks in this industry.

Posted by: Rich Rohrich---------------------

Quote:

Originally Posted by Vic

It's a KTM, so no one will ever have to.

It's a KTM so I know I won't ever have to, and I'm grateful for that.

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crf 450 valves? i heard this.....

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