A lot of bike shops up in the Baltics offer "motohotel" services in the winter. About 20 euros a month for a guaranteed safe, dry, warm warehouse, usually with a trickle charger for your battery.
In Estonia I can help you out with specific places, elsewhere just try googling "moto hotel" with the city name. Or contact the big local bike parts store.
That said... if you want to leave the bike in September, and continue in a few months, then in a few months the roads may not be safe for a Blackbird.
|