what is the standard % of profit you may earn if you let a financer use your registered business name to him?

You can ask whatever you think you are intitled too. There is no set amount. Some companies are recognized by a specific name. and if that were changed it would affect the business. So often when people sell a business a value is put on the name especially if it is well established. This is called Good Will.

Sometimes re numeration is a lump sum or profit sharing etc. You need to sit down with your Financier and agree to a percentage. The best way to handle this situation is to bring your financier in as a partner. therefore you are still listed as an owner and entitled to a percentage of the profits. Often the amount the person invests determines his profit share. If you have invested 20% and he invests 80% capital, you get 20% of the profits. He is also entitled to a salary as well as % of profits if he is running the business.