Cash out refinance or keep existing loan?

[A Bee]

Esteemed BP readers,

I recently posted my first question and was happy to read everyone's posts, thank you very much :)

My question has to do with a potential cash out refinance on a 4 unit building in Los Angeles.  Should I refinance and take some money out or keep the current loan?

If I leave the current loan in place I net cash flow $1,800 a month.  If I cash out refinance the net cash flow drops to $1,050 a month, but get to cash out approximately $140,000.  Both loans are 30 year amortizations. 

The difference in net cash flow would be $9,000 annually ($750 difference X 12 months).  To breakeven, theoretically I would have to put the cash out proceeds, or $140,000 into something to yield 6.4% ($9,000 difference in annual cash flow / $140,000).   And finding an LA apartment deal that yields at least 6.4% is not "market" at the moment.

Also:  The existing loan has a 3.75% interest rate fixed and the new loan would be at 4.125% fixed, both 30 year amortizations.  In addition, adding the extra debt with the refinance would not limit me for buying another property per my lender.  Also, the refinance loan would result in a loan to value of 65% on the property.

What do you think should be the move, cash out refinance or leave as-is? Assuming the cash out proceeds would, if taken, be used to purchase another building.

Thank you in advance!