Titanium Valves Xu10j4rs

[Crazy-legs! 0]

I know Yamaha's YZF250/450 motocross bikes's use titanium valves. But come re-build time, a lot of people change them to stainless because they work-harden and break!

 

Marc.

[Powers 13]

Plenty of useful titanium valve information found here:

 

http://www.k20a.org/forum/showthread.php?t...hlight=titanium

[Rippthrough 98]

I know Yamaha's YZF250/450 motocross bikes's use titanium valves. But come re-build time, a lot of people change them to stainless because they work-harden and break!

 

Marc.

 

Seems a bit strange, stainless steel is a bastard for work hardening too.

 

WRT the link above, I'd recommend having the valve TiAlN coated or 964 Rainbow coated, they're both better options than CrN these days, I've a friend in the US that can help out with that if anyone is making any, and they're no more expensive than the CrN coating. TiAlN is good for 900*C continous use, both will transmit and disapate heat down the coating layer relatively well, whilst shielding the underlying Titanium.

I would probably avoid the DLC coating they were looking at as:

 

a)More expensive

b)It has a tendancy to try to bond with steel via carbon diffusion at high temperatures/pressures

Edited November 24, 2009 by Rippthrough

[petert 588]

I still think your pushing time/money in the wrong direction. Titanium valves might sound impressive down at the pub but the mass of the GTi6 valve train is already down substantially compared to an Mi16. Without a steel crank and rods, you're building a top end that the bottom end can't keep up with. If you've got all that sorted, then fine, but if not, I'd just be fitting solid lifters, better springs and machining the pistons for a safe clearance to suit your cams.