snapped e series valves

[Kx200x]

So I recently did a top end on my e series. I milled the head a little with Emory cloth and a glass plate. Unfortunately I used ebay gaskets and the head gasket isn't a multi layer gasket. I noticed my bike lost its top end today after running great for several tanks of gas. I took the head off and both powervalves were broken. I think it was due to the 1 layer ebay head gasket and the milled head. Where the powervalves go through the holes on head gasket the head has some large releifs. I think I should have taken away some material from the head reliefs to keep the head from pressing on the top of the powervalves. I think that may be why they break so often. They were very we'll lubed and didnt have a spe of carbon. There's a company in Czech @kxpowervalves on facebook that sells aluminum sets I had ordered and should be here this week along with a oem multilayer head gasket. I just wonder if I should go with the steel powervalves as there less likely to break unless these are higher quality aluminum. Im going to keep a spare cylinder so might as well have two sets of valves considering their reputation. Any thoughts.

[brademan76]

Were the power valves that broke the original aluminum ones? Most guys have switched to steel after almost all have broke completely or stripped teeth off them. I'm one of these people and have no complaints about the steel valves. Haven't heard of anyone else having trouble with them either.

[Kx200x]

I spoke with Jeff fredette. At the time I knew I needed the left. It was working but the teeth were a little chewed. He told me the steel collect carbon faster and to stick with aluminum if I could. I found new aftermarket aluminum ones. I think ill order a steel set for my spare cylinder. But I did have a look at my head and could see the powervalve was making contact.

[SpruceItUp]

The steel valves have been great to me. I checked around 40 hours on this top end and they were pretty clean, no major carbon issue here for me.

[Kx200x]

@kxpowervalves on fb has the aluminum ones and they arrived already from Czech Republic. This cylinder has a liner and I Ported it. My first ever not including the stihl leaf blower. I have a nice unmolested cylinder just needs replating ill send it to fredette for porting then replating and get the steel valves. I have a crank that needs a big end bearing and want to send it to someone thay will true it perfectly. The Karting world claims it adds power. Anyone have any crank recommendations? This is my bike 99kx125 e series engine.