it will be a time consuming but you shall approach the police station where the FIR is lodged. Find out date, name & number of applicant, examine the document provided by him to lodge FIR.
if it is before the transfer to your name, inform the police of seller who sold you the bike. also you shall approach the seller, demand full refund for fraudulent sale, inform him you will register FIR for selling a stolen bike and monetary fraud committed.
incase the FIR is after the date of transfer, the issue remains valid. The registration number is allocated to a specific bike under a engine & chassis number with excise records. The case is likely case of Typo Graphical error at the police station registering the FIR.
In any case only a visit to concerned police station will help you.