Budget Head Rebuild question

Has anyone here rebuilt their own cylinder head? I have a 1982 KZ750 4 cylinder with a sticking intake valve. I have years of automotive experience, including full rebuilds of engines.

I bought this KZ as a "barn" find and am hoping to keeping the budget for getting it back on the road as low as possible. I've pulled the cylinder head off and found I can stick my fingernail partially into the #3 intake valve. I don't see any evidence of a thrown rod or any contact between the valve and the piston. Am I somewhat safe in guessing there is some rust build up causing the valve to stick and not fully close?

Would I have a reasonable chance of success to pull everything apart, clean up any rust and carbon build up on the valves, run a brass brush up and down the valve guides, reassemble adjusting the valve clearances? Maybe doing a basic valve lap while I have it apart. I know its not the "proper" way, but I've had quotes as high as $350 just for a basic head rebuild. That's more than I paid for the bike.

Thanks!

Pull the valves and inspect everything.  That will tell the story regarding what is wrong.  Valves hanging open like you describe could be from a bent stem but valves are cheap enough if you look in ebay.  

BTW, $350 for a proper valve job and assembly is not that bad.  

Yes, I do agree that $350 is reasonable for a complete valve job. But like I mentioned, hoping to keep this bike a cheap budget restore and do as much work on my own as I can. Especially when I have the skills, just might not have the specific tools needed.

Did you check the valve clearance/lash before tearing it apart.  It could be that a smaller shim is all that is necessary to fully close the valve in question. 

While I did not, I'm pretty confident that clearance isn't my problem as the gap slowly closed over the course of 2 days with the head just sitting on my bench.