That seems about right for a “jet kitted” carb.I've been keeping records since I bought the bike and I am averaging 40.4 MPG. Compared to others on this forum, this is quite low.
It’ll take off ~5mpg in most instances.
For some, the additional power output is worth it!
Having said this, I opt for fuel mileage over performance. The KLR doesn’t…nor will it ever have any performance to begin with 😂
Having another 25-30 miles (per tank) is always appreciated on my longer riding trips.