Cannondaleriders

what size is the top injector oring(#11 in the engine diagram)?mine is leaking and im gonna try and get a replacement in the morning,i got a ride so no time to order one.Would prefer the size instead of trying to "eyeball" a replacement with my old one...thanx

well since nobody knew i ended up using a size #31 oring,it seemed to be identical to my stock one,it didnt leak so it'll remain on duty.