Ok.  I got my vehicle to move in the directions I was trying to get it to work.  Now, the only problem is, the movement is extremely choppy and "warp" like. 

 

I am sure someone here has experienced this and can point me in the right direction to solving this.

 

 

package powell.rasterland.entity;

import net.minecraft.client.Minecraft;
import net.minecraft.entity.Entity;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.util.AxisAlignedBB;
import net.minecraft.world.World;

public class EntityRasterBike3 extends Entity
{
private int timeSinceRight =0;
private int timeSinceLeft = 0;
private int timeSinceForward = 0;
private int timeSinceBackward = 0;
private double velocity;
private double maxVelocity = 5;
private double velocityBoost = 0;
int direction = 0;

public EntityRasterBike3(World par1World)
{
	super(par1World);
	setSize(1.5F, 0.6F);
}

@Override
protected void entityInit()
{
	// TODO Auto-generated method stub

}

@Override
protected void readEntityFromNBT(NBTTagCompound nbttagcompound)
{
	// TODO Auto-generated method stub

}

@Override
protected void writeEntityToNBT(NBTTagCompound nbttagcompound)
{
	// TODO Auto-generated method stub

}

@Override
public AxisAlignedBB getBoundingBox() 
{
	return boundingBox;
}	

@Override
public AxisAlignedBB getCollisionBox(Entity entity)
{
	if (entity != riddenByEntity) 
	{
		return entity.boundingBox;
	}
	else
	{
		return null;
	}
}	

@Override
public boolean canBeCollidedWith()
{
	return !isDead;
}	

public boolean interactFirst(EntityPlayer par1EntityPlayer)
{
	if (this.riddenByEntity != null && this.riddenByEntity instanceof EntityPlayer && this.riddenByEntity != par1EntityPlayer)
	{
		return true;
	}
	else
	{
		if (!this.worldObj.isRemote)
		{
			par1EntityPlayer.rotationYaw = this.rotationYaw;
			par1EntityPlayer.rotationPitch = this.rotationPitch;
			par1EntityPlayer.mountEntity(this);
		}

		return true;
	}
}

@Override
public double getMountedYOffset() 
{
	return -0.35;
}


@Override
public void onUpdate()
{
	if(timeSinceRight > 0)
		timeSinceRight--;
	if(timeSinceLeft > 0)
		timeSinceLeft--;
	if(timeSinceForward > 0)
		timeSinceForward--;
	if(timeSinceBackward >0)
		timeSinceBackward--;

	super.onUpdate();
	if(!worldObj.isRemote && this.riddenByEntity != null)
	{

		if(Minecraft.getMinecraft().gameSettings.keyBindForward.pressed && timeSinceForward == 0)
		{
			System.out.println("Forward was pressed");
			if(velocity < maxVelocity)
				velocity = velocity + .1 + velocityBoost;
		}
		if(Minecraft.getMinecraft().gameSettings.keyBindRight.pressed && timeSinceRight == 0)
		{
			System.out.println("Right was pressed");
			this.setRotation(this.rotationYaw + 90, this.rotationPitch);
			timeSinceRight = 10;
			direction = direction < 3 ? ++direction : 0;System.out.println("Direction = " + direction);
		}
		if(Minecraft.getMinecraft().gameSettings.keyBindLeft.pressed && timeSinceLeft == 0)
		{
			System.out.println("Left was pressed");
			this.setRotation(this.rotationYaw - 90, this.rotationPitch);
			timeSinceLeft = 10;
			direction = direction > 0 ? --direction : 3;System.out.println("Direction = " + direction);
		}
		if(Minecraft.getMinecraft().gameSettings.keyBindBack.pressed && timeSinceBackward == 0)
		{
			System.out.println("Backward was pressed");
			if(velocity > 0)
				velocity = velocity - .1;
		}

	}

	if(this.riddenByEntity != null)
	{
		this.riddenByEntity.rotationYaw = this.rotationYaw;
	}

	switch(direction)
	{
		case 0: setPosition(posX, posY + motionY, posZ + velocity);
				break;
		case 1:	setPosition(posX - velocity, posY + motionY, posZ);
				break;
		case 2:	setPosition(posX, posY + motionY, posZ - velocity);
				break;
		case 3: setPosition(posX + velocity, posY + motionY, posZ);
				break;
	}


}


}

 

if(!worldObj.isRemote && this.riddenByEntity != null)
	{

		if(Minecraft.getMinecraft().gameSettings.keyBindForward.pressed

Ultimate server crash.

Use a TickHandler to catch the keys and send packets to update the entity.