Can i make an exact copy of my laptops drive onto an external, in case I ever want to make a clean install?

I have windows 8.1 as a default installed on my lenovo yoga 3 pro. I also have a large external hdd, and i just got a new larger ssd to use on my laptop (i will sell the one that came with it). I plan on installing ubuntu when i install the new SSD, but I'd like to copy the original partitions onto my external in a way that if i so chose, I could repartition my new ssd to dual boot windows and ubuntu, or at least reinstall windows from whatever I can copy onto my external drive.

I would use disk imaging software to make an image of your current drive and then restore that image to your new SSD. After installing the software and connecting your new SSD to your computer via a data cable or an external drive, the process is rather straightforward. I used Acronis True Image when I upgraded my SSD.

Here is a review of this type of software - http://disk-imaging-software-review.toptenreviews.com/

Yes you can make an exact copy of your systems HDD, It's a pity that you didn't read about SSD drives they are not that reliable so don't go selling your old hard drive you may need it… Last but not the leased Ubuntu is far from being the best Linux operating system, there are better Linux distributions available