We are missing the,"Customization" section of CC's for this as some of guys on there have modded this.What I can say is that you really need to fabricate some small brackets so you can bolt to the main engine/frame bolts like normal crash bars do and not to the engine which can crack if the bike gets dropped.
You can bolt to the bottom of the engine but only if you secure the top to the engine mounting and I would try and stick to using the engine/frame as the main load bearing points.


Note:Anyone reading this with engine bars notice that mine have been modded with slots instead of holes using a hacksaw.This makes the bars very easy to remove but does NOT weaken their usage(Tested in a slide).