Motorcycle Repair: Service, yamaha vmax, two tanks

Question
Hi, and thanks for reading this question. Now, my bike's a Yamaha VMax but that shouldn't have much affect on my question. I brought the bike into a shop for some service and, after more than two weeks and $500, got the bike back last Friday, with a second exhaust I had lying around installed and the bike jetted - which the place did without asking me first and without using a specific jet kit (I also had the carbs cleaned out and an aftermarket fan switch installed). I've had the bike back for just a few days now and I'm noticing that the fuel economy has markedly dropped. Before, I'd usually get about 90 city miles to 3 gallons before the light went off and maybe 110 on the highway, which is the accepted standard for my model. In the last two tanks I've ridden about 25 miles city and 50 miles highway, and have had to refuel after only 78 miles. I'm not happy and I'd like to get your advice. Thanks again.

Answer
Sounds like they installed larger jets which will hurt you fuel milage, but it shouldnt cut it in half. When you change exhausts you need to rejet and it sould like what they did.Talk to the shoop that did the work and ask them why you lost so much milage.
Good luck and happy riding
Mike