2 inches is all ya need. Light bar extensions are easy to make. Only 4 drilled holes on a plate and a little cutting of the metal of your choice. 1/4 inch aluminum works good and will polish real nice. It is under the headlight anyway so it isn't noticed much.
If ya already have a light bar that doesn't work, let me know. I will look and see if I have 1 laying around, I usually do. The 1300 and 1800 has the same dimensions. The distant from the head light mounting holes.
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This is a headlight extension that pushes the head light out and down to have the same height for my fairing.
I will see if I can find a photo on how I make them.