Module not working?

No experience with the MPU6050 module here.
Here are some I2C suggestions to try:

Pullup resistors on the scl and sda lines are one thing to check.
Does your MPU6050 breakout board provide these?
Are the jumpers on the breakout board used to engage the pullup resistors?

var MPU6050 = require("MPU6050");
You might try
var MM= require("MPU6050"); (and subsequent references to MPU6050 in your code)
as the MPU6050 may already used by the module.

 I2C3.setup({ scl :A8, sda: B4} );
//console.log(I2C3);
 var xgAddress= 0x6B;// Would be 0x1C if SDO_M is LOW
 var mAddress= 0x1e;// Would be 0x6A if SDO_AG is LOW 
 W=require("LSM9DS1").connect(I2C3,xgAddress,mAddress);
// W=new LSM9DS1(I2C3,xgAddress,mAddress);
 W.run();//Get it started

For PICO
//I2C1 sda=B7 scl=B6
//I2C1 sda=B9 scl=B8 shim pins
//I2C3 sda=B4 scl=A8
//I2C2 sda=B3 scl=B10