A method I also use, quite therapeutic walking around with a weed slasher, also helps if you grew up watching Erol Flynn filmsWhen I was a countryside ranger we used to knock the heads off of bracken as it unfurled early in the growing season. This meant that significant amounts of the stored energy used for the early growing was lost to the plant as it hadn't yet got large enough to effectively photosynthesise and had used most of its energy producing the early growth. It really did weaken the areas of bracken that we worked on significantly. I think if you were to use your quad in the early growing season in the way that you've described that you would have a large impact on the ability of bracken to grow. We were working by hand only. Just remember that without the bracken you'll find that your soil structure will change a lot and you may not find it pleasant riding on the quad after a while.

