Rotation Problem of pendulum

hi, i have a problem of rotation of pendulum,it will rotate 70 degree right and -70 left, m using GUI slider to adjust speed, but the pendulum is rotating very very slow, m attaching script please help…

1st script(GUIBUTTON)

var speedselection;

speedselection = GUI.HorizontalSlider (Rect (550, 45, 100, 30), speedselection, 0.5, 1.5);

(min_speed=0.5, max_speed=1.5)

2nd script(pendulum_rotation)

var angle : float ;

var x : float ;

x = 0.0f;

var i:int=1;

var speed:float;

var time:float;


function Update () 

{

        var guibutton:GUIBUTTON = GameObject.Find("Scene").GetComponent(GUIBUTTON);
	time=guibutton.speedselection;
	
	speed = 70/time;
	
	angle = Time.deltaTime * speed; 
  
	if(x>69)
		{ 
			i =-1;
		}  	
		transform.Rotate (0,angle, 0 );

	}
	else if(x >= -70 && i== -1)
	{
		x -= angle;
		if ( x < -69)
		{
		i =1;
		}
		transform.Rotate (0,-angle,0);
    }

i am getting error in transform.rotate(0,angle,0) but if i give value of time to 0.5 the whole script will work perfectly

edited script, 2nd script(pendulum_rotation)

var angle : float ;

var x : float ;

x = 0.0f;

var i:int=1;

var speed:float;

var time:float;

function Update ()

{

var guibutton:GUIBUTTON = GameObject.Find(“Scene”).GetComponent(GUIBUTTON);

time=guibutton.speedselection;

speed = 70/time;

angle = Time.deltaTime * speed; 

if(x <= 70 && i==1)
{
	x += angle;
	if ( x>69)
	{ 
		i =-1;
	}  	
	transform.Rotate (0,angle, 0 );

}
else if(x >= -70 && i== -1)
{
	x -= angle;
	if ( x < -69)
	{
	i =1;
	}
	transform.Rotate (0,-angle,0);
}

}