Itura has a tension measuring device similar to the Lennox
shown in the Lonnie Bird article referenced elsewhere in
this thread. Price is around $140 US.

Suffolk suggests using The Flutter Method. Open up
the throat to max blade exposure, move the blade
guides back away from the blade and put enough
tension on the blade so it won't spin off the wheels.
Turn on the saw. If the blade's under tensioned it
will flutter. If no fluttering then back off the tension
'til fluttering begins then add tension 'til the
fluttering stops. If you start with fluttering, add
tension until it stop.

Repeating - you need to start with enough tension
to keep the blade on the wheels!

And BTW - check the weld before using any blade.
A bad weld that lets loose with the saw running
will a) accordian an amazing length of band in
the blade guard and b) necessitate a shorts change
(DAMHIKT).

charlie b