Five Valve Head

[DRX350]

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

[RCannon]

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.

[DRX350]

40,000 miles or so if maintained and adjusted.

[grayracer513]

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.

[HONDA NO MORE]

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Actually, I work as a rocket scientist and this stuff is a lot more high tech (not to mention interesting) than the outdated SH!T I deal with at work everyday.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.

[Brad_Aus]

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

[erickdj]

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.

[DRX350]

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?