This goes into the vehicles meta located in Update>update>common>data>levels>gtav

Please make sure it is placed in the line under <Initdata> and insure you dont delete the <Item> which starts off the next vehicle otherwise the game will crash on load
(Please scroll down for the next section MUST READ) 

<Item>
      <modelName>policeb2</modelName>
      <txdName>policeb2</txdName>
      <handlingId>POLICEB</handlingId>
      <gameName>POLICEB</gameName>
      <vehicleMakeName>DINKA</vehicleMakeName>
      <expressionDictName>null</expressionDictName>
      <expressionName>null</expressionName>
      <animConvRoofDictName>null</animConvRoofDictName>
      <animConvRoofName>null</animConvRoofName>
      <animConvRoofWindowsAffected />
      <ptfxAssetName>null</ptfxAssetName>
      <audioNameHash>POLICEB</audioNameHash>
      <layout>LAYOUT_BIKE_DIRT</layout>
      <coverBoundOffsets>BIKE_COVER_OFFSET_INFO</coverBoundOffsets>
      <POVTuningInfo>SANCHEZ_POV_TUNING</POVTuningInfo>
      <explosionInfo>EXPLOSION_INFO_DEFAULT</explosionInfo>
      <scenarioLayout />
      <cameraName>FOLLOW_UPRIGHT_BIKE_CAMERA</cameraName>
      <aimCameraName>BIKE_AIM_CAMERA</aimCameraName>
      <bonnetCameraName>BIKE_SANCHEZ_POV_CAMERA</bonnetCameraName>
      <povCameraName>BIKE_SANCHEZ_POV_CAMERA</povCameraName>
      <FirstPersonDriveByIKOffset x="0.000000" y="-0.060000" z="0.000000" />
      <FirstPersonDriveByUnarmedIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonProjectileDriveByIKOffset x="0.030000" y="0.020000" z="0.000000" />
	  <FirstPersonProjectileDriveByPassengerIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonProjectileDriveByRearLeftIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonProjectileDriveByRearRightIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonDriveByLeftPassengerIKOffset x="0.000000" y="-0.060000" z="-0.020000" />
	  <FirstPersonDriveByRightPassengerIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonDriveByRightRearPassengerIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonDriveByLeftPassengerUnarmedIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonDriveByRightPassengerUnarmedIKOffset x="0.000000" y="0.000000" z="0.000000" />
	  <FirstPersonMobilePhoneOffset x="0.155000" y="0.315000" z="0.520000" />
      <FirstPersonPassengerMobilePhoneOffset x="0.136000" y="0.223000" z="0.425000" />
      <PovCameraOffset x="0.000000" y="0.000000" z="0.000000" />
      <PovCameraVerticalAdjustmentForRollCage value="0.000000" />
      <PovPassengerCameraOffset x="0.000000" y="0.000000" z="0.200000" />
      <PovRearPassengerCameraOffset x="0.000000" y="0.000000" z="0.000000" />
      <vfxInfoName>VFXVEHICLEINFO_MOTORBIKE_GENERIC</vfxInfoName>
      <shouldUseCinematicViewMode value="true" />
      <shouldCameraTransitionOnClimbUpDown value="false" />
      <shouldCameraIgnoreExiting value="false" />
      <AllowPretendOccupants value="false" />
      <AllowJoyriding value="true" />
      <AllowSundayDriving value="true" />
      <AllowBodyColorMapping value="true" />
      <wheelScale value="0.267000" />
      <wheelScaleRear value="0.238800" />
      <dirtLevelMin value="0.000000" />
      <dirtLevelMax value="1.000000" />
      <envEffScaleMin value="0.000000" />
      <envEffScaleMax value="1.000000" />
      <envEffScaleMin2 value="0.000000" />
      <envEffScaleMax2 value="1.000000" />
      <damageMapScale value="0.600000" />
      <damageOffsetScale value="1.000000" />
      <diffuseTint value="0x00FFFFFF" />
      <steerWheelMult value="0.700000" />
      <HDTextureDist value="5.000000" />
      <lodDistances content="float_array">
        10.000000	
        25.000000	
        60.000000	
        120.000000	
        500.000000	
        500.000000
      </lodDistances>
      <identicalModelSpawnDistance value="80" />
      <maxNumOfSameColor value="10" />
      <defaultBodyHealth value="1000.000000" />
      <pretendOccupantsScale value="1.000000" />
      <visibleSpawnDistScale value="1.000000" />
      <trackerPathWidth value="2.000000" />
      <weaponForceMult value="1.000000" />
      <frequency value="30" />
      <swankness>SWANKNESS_1</swankness>
      <maxNum value="5" />
      <flags>FLAG_NO_BOOT FLAG_HAS_LIVERY FLAG_IGNORE_ON_SIDE_CHECK FLAG_AVERAGE_CAR FLAG_IS_OFFROAD_VEHICLE FLAG_HEADLIGHTS_USE_ACTUAL_BONE_POS</flags>
      <type>VEHICLE_TYPE_BIKE</type>
      <plateType>VPT_NONE</plateType>
      <dashboardType>VDT_SPORTBK</dashboardType>
      <vehicleClass>VC_MOTORCYCLE</vehicleClass>
      <wheelType>VWT_BIKE</wheelType>
      <trailers />
      <additionalTrailers />
      <drivers>
        <Item>
          <driverName>A_M_M_Hillbilly_02</driverName>
          <npcName />
        </Item>
        <Item>
          <driverName>A_M_M_Salton_01</driverName>
          <npcName />
        </Item>
      </drivers>
      <extraIncludes />
      <doorsWithCollisionWhenClosed />
      <driveableDoors />
      <bumpersNeedToCollideWithMap value="false" />
      <needsRopeTexture value="false" />
      <requiredExtras />
      <rewards />
      <cinematicPartCamera>
        <Item>WHEEL_REAR_LEFT_CAMERA</Item>
      </cinematicPartCamera>
      <NmBraceOverrideSet>Bike</NmBraceOverrideSet>
      <buoyancySphereOffset x="0.000000" y="0.000000" z="0.000000" />
      <buoyancySphereSizeScale value="1.000000" />
      <pOverrideRagdollThreshold type="NULL" />
	  <firstPersonDrivebyData>
        <Item>BIKE_SANCHEZ_FRONT</Item>
        <Item>BIKE_DAEMON_REAR</Item>
      </firstPersonDrivebyData>
	</Item>


-----------------------------------------------------------------------------------------------

Next section will be something most likley new so listen up 

scroll to the bottom of the vehicles meta and before the line </txdRelationships> place this
AGAIN ENSURE YOU DO NOT DELETE THE PRVIOUS ENTRY OR THE </txdRelationships> OR YOUR GAME WILL CRASH

<Item>
      <parent>vehicles_chopperbk_interior</parent>
      <child>policeb2</child>
    </Item>  

All done now move onto the carvariations