Get yourself a Letter of Invitation from the St Petersburg International Hostel. State where you want to go on the LOI application. They will send you a LOI that gives you 30 days in Russia, it may say 30 days in Moscow..but its OK..this is basically all your reservations in one.
I had a standard tourist visa. The LOI didnt mention the motorbike at all, that was dealt with at the border..no problems.
I did need to state the date of entry and the date of exit. You can enter after the stated entry date but you must leave on or before the exit date...failure to do so may result in an unwanted trip to moscow to obtain an exit permit! Its NOT like some countries where you have 30 days from the entry stamp day eg Iran.
Once in the country you must register your visa..its easier to have your sponsors do it, but it can be done at an OVIR office.
Once in side you are free to travel as you like. Just make sure you have an International drivers license, border insurance, and the customs declaration which you to show the police when they stop you every fifty kms.
I was able to register in St Petersburg the day after I entered the country. No other registration was required or asked for.
The Customs declaration is much the same as what you would have got in Uzbekistan. Dont lose it. I had another one spare just in case..figured it would be easier to claim it wasnt stamped than not have one at all.
Let me know if I can give you any more info..still thinking of the Penne Arabiatta from the hotel Nissa!!
Mark from Utrecht crossed Ukraine into Kazakstan last year, I can send you his email if you want it.
Are you visiting Chernobyl?
Close to Antarctica and a long way from reality