Speed limit under the lateral boundries of class B airspace is 200kts, see CFR 14, 91.117(c)wmburns wrote: (The JS41 can't go faster than 250 KIAS. No speeding tickets here). ]
(c) No person may operate an aircraft in the airspace underlying a Class B airspace area designated for an airport or in a VFR corridor designated through such a Class B airspace area, at an indicated airspeed of more than 200 knots (230 mph).