reverend - the uk version has single filament bulbs and the connecter block for each only has 2 wires.
You`d have to splice into the wiring harness to run two bulbs, change the connector blocks and maybe change the whole headlamp as i think one side of the reflector is designed for dip & the other for main.

 

So, has anyone in the USA tried a pair of Sliverstar H13 bulbs?

 

the stock ones the dealer told me are actually H4 bulbs

 

Dealer coujldn't tell me what bulb either.&nbsp\\; I opened mine up to install a headlight modulator.&nbsp\\; They are definietly h13.&nbsp\\; See pics.&nbsp\\; FYI.&nbsp\\; ANyone interested in headlight modulators... Kriss makes great ones and they recently made one specially for Fatbob.&nbsp\\;&nbsp\\; I sent them pics and details about the lights and within a week they had them for sale and listed on theior site..., http://www.kriss.com/hdfatbobmod.php