Flights:
Cheapest flights normally to Tampere from Milan/Bergamo Orio al Serio you get from Ryanair. Check also other companies like Finnair, Blue1, SAS, Lufthansa and so on. They often have special offers to Helsinki.
Info and accommodation/Tampere:
www.tampere.fi Tips of cheap accommodations in the centre of the city. Click "Hotel".
For example Omenahotel 46 €/4 persons max. www.omena.com/frontpage
Several Express Bus departures from Helsinki Aiport to Tampere city centre/bus station.
Motorcycling routes:
Some motorcycling routes in Finland you'll find in www.everytrail.com or you can contact motorcycle associations.