How to fix the fps controllers, that has rigid body and network

Hey, I'm working on a multiplayer fps. I'm the guy that are doing the network coding. My problem is that the fps controller that comes with unity uses a character controller and some on my team that are making some weapons need to use rigid body on the player(for a grappling hook), as i know, and also from my results those two don't mix so well. I get this weird bug where when another play joins the game he just fly away on the other guys screen. But on his own screen it is the other guy. If i remove rigid body it works perfect.

Does anyone know a fix, or anything that can help?

Just say if you need some source code or anything to help solve the problem.

Thanks in advance :)

My Character script with some network

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 // Require a character controller to be attached to the same game object
 [RequireComponent(typeof(CharacterMotor))]
 [AddComponentMenu("Character/FPS Input Controller")]
 
 public class FPSInputController : MonoBehaviour
 {
     private CharacterMotor motor;
     
     //Netværk variabler
     private float lastSynchronizationTime = 0f;
     private float syncDelay = 0f;
     private float syncTime = 0f;
     private Vector3 syncStartPosition = Vector3.zero;
     private Vector3 syncEndPosition = Vector3.zero;
     
     void OnSerializeNetworkView(BitStream stream, NetworkMessageInfo info)
     {
         Vector3 syncPosition = Vector3.zero;
         Vector3 syncVelocity = Vector3.zero;
         if (stream.isWriting)
         {
             syncPosition = rigidbody.position;
             stream.Serialize(ref syncPosition);
 
             syncPosition = rigidbody.velocity;
             stream.Serialize(ref syncVelocity);
         }
         else
         {
             stream.Serialize(ref syncPosition);
             stream.Serialize(ref syncVelocity);
 
             syncTime = 0f;
             syncDelay = Time.time - lastSynchronizationTime;
             lastSynchronizationTime = Time.time;
 
             syncEndPosition = syncPosition + syncVelocity * syncDelay;
             syncStartPosition = rigidbody.position;
         }
     }
     // Use this for initialization
     void Awake()
     {
         if(networkView.isMine)
         {
         lastSynchronizationTime = Time.time;
         motor = GetComponent<CharacterMotor>();
         }
         else
         {
         enabled = false;
         }
     }
     
     private void SyncedMovement()
     {
         syncTime += Time.deltaTime;
 
         rigidbody.position = Vector3.Lerp(syncStartPosition, syncEndPosition, syncTime / syncDelay);
     }
 
     void InputMovetment()
     {
         // Get the input vector from kayboard or analog stick
         Vector3 directionVector = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
         
         if (directionVector != Vector3.zero)
         {
             // Get the length of the directon vector and then normalize it
             // Dividing by the length is cheaper than normalizing when we already have the length anyway
             float directionLength = directionVector.magnitude;
             directionVector = directionVector / directionLength;
             
             // Make sure the length is no bigger than 1
             directionLength = Mathf.Min(1.0f, directionLength);
             
             // Make the input vector more sensitive towards the extremes and less sensitive in the middle
             // This makes it easier to control slow speeds when using analog sticks
             directionLength = directionLength * directionLength;
             
             // Multiply the normalized direction vector by the modified length
             directionVector = directionVector * directionLength;
             
             // Apply the direction to the CharacterMotor
             motor.inputMoveDirection = transform.rotation * directionVector;
             motor.inputJump = Input.GetButton("Jump");
         }
     }
 
     // Update is called once per frame
     void Update()
     {
         
         if (networkView.isMine)
         {
             InputMovetment();
         }
         else
         {
             SyncedMovement();
         }
         Screen.lockCursor = true;
         
     }
 }

My Network script

 using UnityEngine;
 using System.Collections;
 
 public class NetworkManager : MonoBehaviour
 {
     private const string typeName = "UniqueGameName";
     private const string gameName = "RoomName";
 
     private bool isRefreshingHostList = false;
     private HostData[] hostList;
 
     public GameObject playerPrefab;
 
     void OnGUI()
     {
         if (!Network.isClient && !Network.isServer)
         {
             if (GUI.Button(new Rect(100, 100, 250, 100), "Start Server"))
                 StartServer();
 
             if (GUI.Button(new Rect(100, 250, 250, 100), "Refresh Hosts"))
                 RefreshHostList();
 
             if (hostList != null)
             {
                 for (int i = 0; i < hostList.Length; i++)
                 {
                     if (GUI.Button(new Rect(400, 100 + (110 * i), 300, 100), hostList[i].gameName))
                         JoinServer(hostList[i]);
                 }
             }
         }
     }
 
     private void StartServer()
     {
         Network.InitializeServer(5, 25000, !Network.HavePublicAddress());
         MasterServer.RegisterHost(typeName, gameName);
     }
 
     public void OnServerInitialized()
     {
         SpawnPlayer();
     }
 
 
     void Update()
     {
         if (isRefreshingHostList && MasterServer.PollHostList().Length > 0)
         {
             isRefreshingHostList = false;
             hostList = MasterServer.PollHostList();
         }
     }
 
     private void RefreshHostList()
     {
         if (!isRefreshingHostList)
         {
             isRefreshingHostList = true;
             MasterServer.RequestHostList(typeName);
         }
     }
 
 
     private void JoinServer(HostData hostData)
     {
         Network.Connect(hostData);
     }
 
     void OnConnectedToServer()
     {
         SpawnPlayer();
     }
 
 
     private void SpawnPlayer()
     {
         Network.Instantiate(playerPrefab, Vector3.up * 8, Quaternion.identity, 0);
 
     }
 }