Is it possible to pull data off a linux hard drive using windows 8.1?

Windows only naturally understands Windows file systems... but you can install more.

Ubuntu by default uses ext4 these days, so you probably need something like this :

http://www.ext2fsd.com/

It appears that the ext2fsd solution has not been updated in over 2 years, and has outstanding known bugs that indicate they create data corruption, so I would be cautious about that approach.

I think you would be be better off accessing the filesystem from a native OS. I would suggest that you prepare a bootable image of the Ubuntu desktop installer ISO for the version you have/had installed on the dead PC, and use that to boot your Windows 8 PC.

1. On the Windows 8 machine, download the appropriate image from Ubuntu.
2. On the Windows 8 machine, either burn the image to a CD/DVD, or make a bootable image on a USB/flash device (I prefer the PenDrive Rufus tool on Windows).
3. Power down the Windows 8 machine and attach the dead Ubuntu machine's disk via SATA (before power up) or USB (before or after).
4. Insert the Ubuntu CD/DVD/USB/flashdrive in the Windows 8 machine.
5. Power up the Windows 8 machine; when it starts, be sure to configure the BIOS to boot from CD/DVD or "removable device" (USB/Flash) before the local HDD, or choose it from the boot-time BIOS selection.
6. At the Ubuntu Live Welcome screen, select "Try Ubuntu", not "Install Ubuntu", and allow the system to load.
7. Look for dead system's disk on the Live Ubuntu's desktop/Nautilus/mount list.
8. Navigate to the files on the old linux drive that you want to recover, and copy them to a partition on the Windows 8 machine, a USB/flash device, or network storage.
9. Shutdown the Live Ubuntu image and remove the Ubuntu CD/DVD/USB/flash device from the Windows system.
10. Restart the Windows machine under Windows 8 and access the files from the location you copied them to.