Here's a little tip to other BMW Sportster builders.
The Marlin supplied engine mounting brackets are much thinner than the orginal BMW alloy ones, so you need to use shorter bolts.
I thought I'd use the originals which, as I tightened them up, hit the bottom of the tapped hole in the engine block.
I foolishly snapped one off in the block today !
Now i'll have to spend time extracting it before I move on!
best regards to other builders,