It does not give a tension spec like the harleys because buells do not have a tension adjustment. At least the xb doesnt. I think the tubers do so they will have the tension guidelines in the manual.
The 2004 manual says
"The drive belt tension on a new belt will be considerably tight
and will loosen after approximately 1000 miles (1600 km).
The drive belt tension is automatically maintained by the idler
pulley. Axle alignment is not adjustable.
Replace drive belt and idler pulley assembly:
● At every 25,000 mile (40,000 km) service interval."