What size wire is run to it?Have you checked your alternator output?
Sounds like you might have a couple of different issues.If you're losing bulbs in a short period of time, the culprit is usually a bad regulator. Too much voltage means too much current and too much current makes things pop.That said, it should be pretty hard to blow a 55W or 65W bulb since your charging system usually isn't capable of powering one, let alone creating more power than one can handle.The first place to start would be getting a new headlight bulb onto the bike (I don't recommend anything over 35W, switch to HID or LED if you want a brighter headlight) and then hooking up a voltmeter. Make sure you're not going over 15V, even when the revs get up there. If you're using an AGM or LI-ION battery, 14.5V is really as high as you want to see.
Without an adjustable power supply or other testing tools, diagnosing the regulator can be difficult. The best method for the home mechanic would be to measure voltage across the battery terminals with the bike running. Give it some revs and you should see the voltage increase, but then cap out at a max of 14.5V.Our unit is bench calibrated to 13.9V, which usually ends up being about 14.2V in the real world, but due to stacked tolerances this number can be higher or lower. What you're looking for is that the voltage never exceeds 14.5V, regardless of how high you rev it.