Size of the 'oxygen sensor' nut?
 

How big, in mm, is the nut on the oxygen sensor on the catalysator? I need to get a spanner that fits but the bike is at home. :/

goines
22mm or 7/8" will work.

Ed

Thanks. :)

How often should that part be replaced?

When it goes bad, or gets "lazy". To get a accurate reading it should prolly get hooked up to a motronic scantool, and hopefully you can read the voltage with a line graph. A meter can be used in some cases (depending on the meter). I havent heard of a milage where they should be changed at.

John