ATC70 E22 head

[Tomcall]

I have a 1974 ATC70 that I have restored. I had an 88cc with racing head in it and exchanged the top end with a stock 1986 TRX70 as my grand kids needed a little more ummpf for their ride. So I have an E22 head that I rebuilt on it and I think I may have replaced a flat head piston with a domed piston because it looked pretty clean and added new rings. I am hearing a metallic clink which I fear may be the piston hitting the valves. Can anyone comment on this set up and if I should have gone with flat head piston?
Thanks

[Tomcall]

Ok guys I discovered if you keep researching you can usually find the answer to your own questions............... I read on Dr..ATV that with the E22 head a flat head piston is needed. So now we all know. As it happens I had a couple of pistons in decent shape lying around. It is amazing all the parts one accumulates when you get into restoring these old machines. I swear I must have gone a parts ordering frenzy at some point. I have lots of new seals and misc. parts still unwrapped. It is handy if you remember what you have. When i go searching for some odd part it's like Christmas all over again: "WOW, I didn't know I had that...."