Just noticed my math was off by 1mm.NOT 15mm, but 14mm,,,,What can I say it was tired and had been working with kids all day!
Red swingarm is from a RF 900 conversion. The braced bare aluminum is a gsxr 1100 swingarm.
The sleeves from the rf 900 willl fit inside the gsxr to allow the same picot bolt. A few mm from each side will be removed to fit in the frame. It's at the machinist now.