If you want to compare FNB loans easily there's a new app for that, CompareLoans.co.za. It's free to use with up to date data, and access is also not gated, which is convenient.
Most financial institutions (think banks, credit unions etc.) who offer vehicle finance will finance motorbikes. You'll have the choice between a secured loan (ie the bike will be used as a guarantee for the lender, and you could lose it if you default on your repayments) and an unsecured loan...