Five Valve Head

Lets not forget about the Ferrari 5 valve V-8. Any one want to adjust a 40 valve engine? How 'bout a valve job...

Ouch... If you needed valves, it would be best just to trade it in....

I know its not a streetbike thread, but what sort of lifespan could someone expect for these valves on the streetbike? It does sound like a rebuild is out of the question.

40,000 miles or so if maintained and adjusted.

All the comment about the yz's 5 valve engine and know one has mention the awesome reliability, I owned A 2000 yz426 that never had one engine problem or needed a valve adjustment sold it in 2008.Now I have a newer yz450 and love it.
The reliability has nothing to do with the design as far as 5 vs. 4 valves, and everything to do with the choice of materials for valves, seats, hard coatings, etc., and with the high quality of manufacture. It's really not rocket science.
The reliability has nothing to do with the design as far as 5 vs. 4 valves, and everything to do with the choice of materials for valves, seats, hard coatings, etc., and with the high quality of manufacture. It's really not rocket science.

Actually, I work as a rocket scientist and this stuff is a lot more high tech (not to mention interesting) than the outdated SH!T I deal with at work everyday. Our sport has seen a lot of technological advances in the last few years. The way I see it we are riding the equivalent of at least a stock car for around $5000, pretty cool if you ask me.

Lets not forget about the Ferrari 5 valve V-8. Any one want to adjust a 40 valve engine? How 'bout a valve job...

we have a 40 valve engine, lamborghini 10cyl 4-valve... thank god for hydrualic lash adjusters

The way I see it we are riding the equivalent of at least a stock car for around $5000, pretty cool if you ask me.

yeah, that is very cool. these 450 engines really put a smile on anyone's face, or it totally terrifies them.

we have a 40 valve engine, lamborghini 10cyl 4-valve... thank god for hydrualic lash adjusters

Or how 'bout that Cadillac Sixteen concept? 64 valves anyone?

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