Stock 650 style shim under bucket & retainers

I’ve seen these factory parts used on the bigger KZ / Z1’s. Are they strong enough for high horsepower / RPM  abuse?
and are the spring retainers aluminum alloy or steel? Have a guy wants to cut cost’s on a top end rebuild on a dragbike engine. He says he has a stock set. Wants to use on high lift cams. Asked me to set them up. I’d hate to see it fail and ruin the engine?

I don't know how robust the 650 parts are, but I do know the retainers are steel.  I've never seen any stock engine, motorcycle or car, that used aluminum valve spring retainers.  But then again, I'm far from all knowing regarding such matters.

As the previous reply.
Stock retainers are steel.
No problem using them.

APE sells titanium valve spring retrainers.

 

No eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configurationVery common HP mod. 
Steve

Yoshimura Japan offers H/D spring kits with some fancy steel spring retainers for the Z1, Kz900, and Kz1000's motors. They still offer both styles of valve keepers too!!

 

 

Yes, of course I know they are used for ever, I was just checking on alloy / material? Hoping these are Titanium. Just for eBay sale. I’m done. I don’t need them. But 1/2 are worn with a grove depression from cam lobe?

Yes, of course I know they are used for ever, I was just checking on alloy / material? Hoping these are Titanium. Just for eBay sale. I’m done. I don’t need them. But 1/2 are worn with a grove depression from cam lobe?

I bought a pile of stuff other day. This stuff was in a box with it all. Picked up KZ  z nice set of Wisecos, 72mm, with broke fin block.
and a 76mm block big liner set. eBay items after I clean and glass bead everything

Z1B # 080,285 case with 81mm bored spigots for the 1200 sleeves. Was a nice job! 76 Frame sitting, waiting on a New York State title! 12 weeks time frame!
trying to use new smart phone app? WTF?