Question about paying down %age of mortgage with investment funds

[Jay Ipswich]

Hello all, I'm a newbie who just signed up looking for some financial advice.

I'm a single person, aged 43, who recently bought a new home in the CA Bay Area putting 20% down left with a mortgage of 720K. My mortgage payment is $4500/month which is roughly 60% of my net salaried income. I have a 6 months worth safety net cash put away in my savings for unexpected incidents such as job loss, urgent home maintenance, etc. 

I aggressively contribute the max 17k/year towards my 401k (6% of it is matched by my employer); and the max 6.5k/year towards my roth ira. The remaining 40% of my net income is sufficient for my regular lifestyle expenses.

I also own an investment property which has 140k mortgage; rental income $1700/month; current appraised value 270k.

So, as a single person filing taxes, my total mortgage amount spread across both properties is 860k.

I have a brokerage investment account with a sprinkling of stocks/mutual funds valued at 100k. My roth ira that i've been contributing to for the past several years has funds valued at 75k.

In light of the above --- my question is whether it would make financial sense to liquidate my investment account of 100k (and incur cap gains taxes); and pay down my personal home mortgage so I reduce my total mortgage liability or leave things as is? I would put myself at a 5 on a risk taking scale of 0 to 10.

Appreciate your comments or suggestions.