Money invested is $60K + $25K.
Rents after expenses is 10,800 - (2500+864+972) = $6,484. Since it costs you 4.5% for the HELOC, subtract that out before you calculate a return. Otherwise it's like this. Your return is $6,484/$85,000 = 7.6%.
Your vacancy is rather high. I use 5%. Your maintenance is light, I use 10%.
In any case, it's less than 7.6%. That is pretty low.