Assuming you travel on GB docs you must have-
Passport with Visa
V5
Driving License + IDP
All originals. No translations needed, although V5 headings translated can be helpful if they want to crawl all over it looking for numbers.

You must have basic road insurance with a certificate issued by a Russian Ins Co. Buy this at the town before or at the border - about £35 for 2 months for a bike.

At borders, ride slowly to head of the first queue - no-one seems to mind and it can save you hours. I found the border at Zilupe (LAT) very busy (took me nearly 5 hours this year, and I had passed over 100 cars in the arrivals queue!) whereas the year before at Narva (EST) I sailed through in less than half an hour.

Have a few Roubles - they used to ask for 120 for the paperwork, but didn't this year. ATMs everywhere once in.
At the border they will give you a Temporary Import Permit for the bike. This is then the equivalent of a V5. Be sure it is valid for as long as you need. They take it back at exit border so be sure to leave before it expires. If re-entering RUS you get a new one each time, though the same Ins Cert is OK if still valid.
Once in RUS you must always have your Passport with you. If using a vehicle always also have the Import Permit, IDP and Ins Cert. These willl be inspected at the regular roadside police checks. A right pain in the arse, but just a fact of life - smile and be polite and helpful, they are only doing a job and once they see everything is correct they want rid of you, so they can look for irregularities with someone else and get bribes from them.

Cant help on Magadan but I know there are helpful bike groups all over RUS. Othere will reply.

Enjoy - its a great (in both meanings) country with wonderful people. Its the politics that get up my nose!

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