Before you drill the head off, at least give it a go with your allen wrench, what do you have to lose if you are going to drill the head off, you could even hammer in an over sized Torx bit, and give it a go, drilling the head off would be my last resort.

 

I have a good sized pocket torch kit with a solid tip adapter I use to heat bolt heads, some propane kits will have the solder tip also, much cheaper than an induction wand.

 

If it were me I would soak it with PB Blaster a few times over a few days, then hit it with an impact driver. I have a Dewalt 1/4" cordless impact driver that really works great for stuck bolts.

 

also, I would put back in any bolts you have removed and tighten then up before trying to get out the stuck ones

 

Thanks to everyone for all of the input. Based on all the recommendations and the resources available to me, here's what I did: I ended up drilling the heads off of the stuck bolts. It took about a minute or 2 per bolt taking my time and checking everything as I went. I knew I was there when the washer would start to spin with the drill. That allowed me to get the outer primary off and left about 3/4" of the bolt shanks exposed. Also left plenty of space to shoot some PB Blaster in the holes with the stuck bolts. After letting them soak for about 20 minutes, they practically unscrewed using just my fingers. Lessons learned and moving on to the actual job I started yesterday.

 

I was thinking you would grab them with some type of wrench or vice grips. I a, curius why they came off so easy at this point? wrong bit? grinding loosened them? pb blaster got in?

Derby bolts I have chisled. Was before I fell in love with PB blaster.

 

Just in case you're not aware, when you start putting it back together be sure to use a thread chaser and clean up those threads.

 

I know this will get all kinds of responses but here goes ... Thread chasers are made to do just that ... Their cut is less aggressive and they do a good job of cleaning out the existing threads without an aggressive cut

 

Additionally, there are different length screw/bolts that hold the primary cover on so make sure you get the correct length in the correct holes.

You did not state the year and model of your bike so make sure you go to the H-D parts listing and get the correct length bolts.
https://www.harley-davidson.com/us/e...s?aribrand=HDM

Example:

 

2015 Road King. I've got that all squared away, thanks. The 4 bolts toward the front are the long ones and happen to be the ones that gave me the problems. The remaining 9 are the shorter ones.