Ok I've got a 08 street glide factory came with a 96 vin # on bike and motor say 96. But derby cover say 103 so does air filter cover and has a dyno fuel pack. So my question is how can I tell if my motor has been upgraded to a 103 from a 95?

 

Pull the head and measure the bore

 

Brads suggestion would be the most straightforward approach.
Scott

 

IIRC, the 103" motor was not available in the FLHX until 2011 with the PowerPak option; probably a 96" motor. However, if you suspect different, check static compression. The 96" motor should see about 180psi and the 103" motor should see about 190psi, both at sea level so adjust as required. Numbers may be off a bit depending on gauge, test procedure, battery condition, etc. but the point being that the 103" motor will put up higher static numbers than the smaller bore 96" motor. Still betting it's a 96" motor though.

 

Didn't you get anything from PO, or was this bike purchased at dealer? Could just be someone got ahold of 103cu/in covers and swapped on your 96cu/in bike to lead others into "thinking" it was a 103. Hope it wasn't highlighted as perk in your purchase...