2004 Honda 500 using a lot of gas???

I have a 2004 Honda Foreman Rubicon 500 with that hondamatic transmission in it. A friend of mine has an 02 Honda rancher 350 with the usual foot shift transmission. When we go on day-long rides, we notice that my atv uses a lot more fuel then his. If he uses a 1/2 tank; I’m near empty. I was wondering if this is normal or not. And if not what can we look at to fix this problem? We both have the same mods to our atvs; warn 424, 2" lift, disk brake conversion. I don’t understand why I burn so much more fuel. And with a bigger tank. Any suggestions will be helpful. We keep our atvs in top condition and regularly change oil and filters. Any questions you can email me, respond to this post, or direct message me. Any suggestions on how to fix this is appreciated!!