Welcome to the site !!
Sorry for the late reply
..... To answer your question , no you do not have to remove the engine from the frame to do a head or even cylinder and/or piston replacement ..... however , I would not recommend doing this without a Factory Honda Service Manual , so you don't miss anything when disassembling or assembling the engine components .... the last thing you want to find out after you got it all back together is that you missed something .... so I would not attempt it without that manual , period .... With the manual , it should be a fairly straightforward job and should not take more than a few hours from start to finish (2-5 hours) , basically , you should be able to do this , and have the bike running the same day without complications ... , but don't rush it , being thorough is better than being fast ...