[Mddtx]

My Gas Milage went to crap after I installed custom exhaust. I can literally watch the gas gauge bars go down as I ride. Anyone have any ideas? 2019 Z125.

 

[AL Terry]

Twisting the throttle more to hear the nose emanating from the custom exhaust?

 

[Mddtx]

No. Just driving as normal

 

[DioptricStraw]

Are you still using the 02 sensor? It's possible that you have an exhaust leak before the sensor and it is reading lean and adding a bunch of fuel. It will set a check engine light but you could try unplugging the o2 sensor and drive around, it should put it into a default fuel trim mode.