spurious ouput
I am going to bet you are using a .714286 MHz phase detector frequency, and this is just that spur (R=35, N=224). Try:
1) Using lower divisor numbers (higher phase detector frequency), such as R=15 and N=96. This will give you a higher phase detector frequency of 1 2/3 MHz
2) Add an RC lowpass filter at the VCO tune port to filter out phase detector spikes at 1 2/3 MHz. I would put in a lowpass with a 3 dB corner at around 20 KHz, and see if you like it better. (Whenever you add an additional lowpass filter you compromise the phase margin of the control loop, so you want to keep the lpf corner frequency say 20X the loop bandwidth, which I assume you correctly state as 1 KHz).