Any cycle tracks on the banks of the water of leith edinburgh?

Yes

Water of Leith
From - to: Balerno to Edinburgh

Length: 10 miles

Type: Towpath and railway path, mostly traffic-free (on-road links to stations at either end) and mostly downhill

Access: Railway stations at Curriehill, Kirknewton, Kingsknowe and central Edinburgh

The ride begins at Balerno High School,
which can be reached via quiet roads from
the stations at Curriehill or Kirknewton.
Here you join the traffic-free route beside
the Water of Leith, whose waters rise in
the Pentland Hills and flow into the Firth
of Forth at Leith. If you are lucky you
may glimpse a kingfisher, or even an
otter, as you pedal downhill with the city
of Edinburgh spread out before you.
At Colinton you follow the old railway line
through a long tunnel, and at Slateford
aqueduct the route joins the Union Canal
into Edinburgh where you emerge at
Fountainbridge. From there you can follow
the Route 75 signs to the Meadows and
the junction of Routes 1 and 75. Head
into the city centre for Waverley and
Haymarket stations.
If you want a longer ride, why not head
westwards away from Edinburgh when
you reach the Union Canal? This will take
you to the Falkirk Wheel, the world’s
only rotating boat lift, at the junction of
the Clyde & Forth and Union canals.
The infamous Burke and Hare were
labourers on the Union Canal before they
diversified into the more lucrative business
of supplying bodies for dissection by
Edinburgh’s teaching hospitals.
Cyclists on canal towpaths must carry a
canal cycling permit.
These can be downloaded from
waterscape.com/cycling/permit.html
or obtained from British Waterways on
01923 201120.

I don't think that the Water of Leith offers much for cycling. It has various walkways through most of Edinburgh but they are not really suitable for cycling.
The Union Canal has a good walkway that can be cycled from the Lochrin Basin to the Falkirk Wheel and from there you can follow the Forth & Clyde Canal towpath to Bowling where the canal joins the River Clyde on the outskirts of Glasgow.

There is a track along the banks of the Water of Leith - The Water of Leith Walkway. You can cycle along most of it, but you will have to push the bike in places and there are some staircases. See the Wikipedia article:
http://en.wikipedia.org/wiki/Water_of_Le...

There is also a track along the side of the canal:
http://en.wikipedia.org/wiki/Union_Canal...

If you are cycling in Edinburgh, it is worth buying the cycle map produced by Spokes, an Edinburgh cycling group. This costs about £5 from a book or cycle shop.
http://spokes.org.uk

There's a cycle path which goes along the union canal and you can follow it from Edinburgh right through to Glasgow.

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