It has been 7 years since my bankruptcy was discharged how much longer before I can get a motor home financed

I would go down see which one you like, They will do a credit check, and The amount of Down Payment could Greatly increase your chances, They will say yes or no.
I don't know if there is a set number of years, and if there is, 7 may be it.

Since it's been 7 years since a Chapter 7 bankruptcy you should be able to get approved for a loan with a hefty downpayment you should be approved as well. If you want to file bankruptcy again you can do that too as it's been 7 years but you will find the rules have changed a lot since then.