Re: just looking for some relitivly cheap entertainment.
First off, welcome to the forum. There are a lot of friendly, talented and creative builders here.
I think you may have lost me with the idea of turning the engine 180 degrees and turning it 90 towards the front. I'm not sure why you would want to do so.
Maybe you can better clarify why you would want to take something as simple as the way it's designed to function and make it more complex than need be.
Anybody here will tell you that getting these cheaply made toy engines to run correctly and with any degree of reliability is a challenge in itself.
They are what they are. They will never be what they aren't if that makes any sense to you.
I'm not trying to discourage thinking outside the box but for all practical purposes build your bike, ride your bike and have fun with it, that's what its all about.
There will be a lot of obstacles to overcome many of which I'm not sure are feasible, but I don't claim to know everything by any means.
Anyway I wish you luck and will be interested in seeing how this will progress.