I think that your ans

Ngoc-Tuan Vu supplied the formulas, so let me supply some text:

Does this help?

P.S.: I answered yesterday, but my first answer seems to have gone to the nul: device :(

Ngoc-Tuan Vu provided the correct details but there are some small calculation errors and the final time is incorrect, it should be 

  t= (a + 2b + c)/V

Also a = (pi - 2Alpha)r1  Alpha in radians

or     a = (180-2Alpha)*r1*pi/180  Alpha in degrees

and same for c.

Just make sure if you work either in radians or degrees otherwise apart from these minor issues his methodology is correct

For N1 = 800 rpm I get

V = 10.4666 m/s

alpha = 0.0583 rad

a = 378.124 mm

b = 2994.3 mm

c = 977.457 mm

d = a + 2b + c = 7344.81

t = d/v = 7344.81/10.466/1000 = .701733 sec

If you omitted all the math and just used d = pi*r1 + 2L + pi*r2

you get d = 7335.2  and  t = 0.701739

So there is only 0.000006 sec difference due to large distance between the pulleys. Math versus practical engineering and experience :)

@Gregory Diana

Yes your answer really help a lot its an exact answer Thank you