youll only bend a valve if you put the cam back out of time badly or snap a cam chain whilst its running or the collets let go or some other freaky mishap,the valves might best be left to a shop as you need a spring compressor to remove and install the collets,you can remove the valves easily without a compressor.with the head on the bench and a ball of rag in the combustion chamber ,place about a 14mm socket over the retainer and strike it with a hammer,the rag should stop the valves opening so the retainer will compress the spring and the collets will jump out,have another rag around the collet area so they dont fly off,you could then wire wheel the valves and clean all the carbon out then give the head to a shop to lap and replace the valves saving a bit of money,,or buy a cheap valve spring compressor,i had to make up a sort of adaptor for my automotive type so make sure itll work on the small honda head!!,make a cardboard square and number it 1 to 4 and pierce the valve stems into it to keep them in order,,they must go back into the original positions in the head..there are two metal shims ,one under each spring!(two per valve)!they can be hard to see as they are quite thin,a good little magnet on a stick is handy to lift them off,dont lose any collets.,you might even be able to use your other head?if you can get it running well enough to ride without pulling the head thatll be cheap,once you open it up youll need to buy gaskets and plan A can become plan B over night ,.you said your new to this type of stuff so maybe the less you have to do internally the better,good luck.
