Visas and immigration are totally separate from the issue of a temporary import certificate for your bike which is a customs issue!
For general guidelines try www.waytorussia.net
From my understanding of the process, one car trip to Russia from the UK, the time period depends on 2 things...
1 Which border crossing (posts on WTR website)
2 Type of visa (inferred from advice on WTR website and my experience)
My experience extends only to "private" invititation visas - for this - at Finland, Nuijamaa/Russia, Brusnichoye you get 10 working days.:-(
The above website, transport section, implies you ought to get up to 30 days on a tourist visa.
The trouble is, none of the bike people on HUBB understand enough of this in order to provide meaningful information - though they manage to travel across Russia, year after year.
I for one would be interested to know what the official periods are.
Hopefully , I've clarified the problem, even if I don't have the exact answer.
Note - I described my experience of extending the t.i.c. - on HUBB and on WTR - my russian trip write up.