intake valve stuck

[motochamp250]

I have a 1971 Honda SL125 that has been sitting for about 5 years. I have everything ready to run, but my intake valve is stuck slightly open, hindering my compression.
If you have any ideas on how to free the valve without pulling the whole head, b/c that is a real pain to remove the entire engine and tranny, I would greatly appreciate it.

Thanks,
JR