Mikuni BS34 CV

I wouldn't expect the stock jets in a BS34 straight off an XS650 to suit an SR. 

Here's a link to the BST34 (which is a different carb to the BS34 used on the XS) as suited for SR use:

www.sr500-owners.de/tech/partsdb/data/bst34.html

For SR use: Main 165, Pilot fuel 45, and Pilot air 80.
Pilot Screw set (part 34 on diagram): 1.5 turns out seemed optimal for me at sea level, whereas diagram says 2.5 turns out.

The standard jetting above is designed for use with standard exhaust and standard airbox/filter.

Edit: Bear in mind the BS carb used on XS's is different to the BST used on the SR, so whether my jetting suggestions re: BST are still valid is a judgement call.

The BS34 starts off with 132.5 main and 42.5 pilot fuel.
www.xs650.com/threads/bs34-carb-diagram-schematic-exploded-view.44960/