First off, I'd like to note that the implication that you cannot use the system clipboard from terminal Vim is false. I use it all the time. (This implication isn't in your question, but it is in the comments.) So if I were in your situation, I would simply install a different Vim package that does include the +clipboard feature.
That said, here's a proof of concept which uses a tmux buffer and the system() function to provide (just) the functionality you asked for:
nnoremap <silent> yy yy:call system('tmux set-buffer -b vim ' . shellescape(@"))<CR>
nnoremap <silent> p :let @" = system('tmux show-buffer -b vim')<cr>p$x
These mappings use the standard yy and p commands to perform the actual yank and put, but include system calls to save the contents of the unnamed register in a tmux buffer after yanking and load the buffer contents back into the unnamed register before putting.
N.B. If I were using this in earnest, I would extend this and tidy it up a fair bit (for instance, with these mappings you can now only p things that you have previously yanked with yy: the easiest way around this is use <leader>yy and <leader>p as the triggers), but this shows the basic functionality.
Here's another version which instead uses tmux's send-keys to directly copy over the contents of the unnamed register when you yank, which in some ways is cleaner, and avoids the problem with the p mapping described above:
nnoremap <silent> yy yy:call system('tmux send-keys -t 1 ":let @\" = \"' . shellescape(@")[1:-2] . '\"' . "\r\"")<CR>
Currently this is losing the newline at the end of the yanked line: it could probably be tidied up not to do so.
tmux, you simply want to be able to yank/paste between two different instances ofvim, right? – pfnuesel Apr 21 '16 at 04:03yycommand in one pane andpinto another pane. I can't use the system clipboard because my non-gui version of vim does not have the clipboard compiled into it. I've tried many of the various solutions recommended but nothing seems to work. – StevieD Apr 21 '16 at 13:24tmuxhas a "copy mode", but it's a bit awkward to use. It also has the:set-bufferand:paste-buffercommands, as well as some other related commands (see theBUFFERSsection intmux(1)). Not entirely sure how to run this from Vim (maybe something with:bind-key -n yy ...?) It also has theMsterminfo extension to interface with the clipboard (with:set-clipboard). – Martin Tournoij Apr 21 '16 at 19:04