Honda trx 400 swap why?

Description:

Took this in px around 6/7 months ago. Being completely honest I don't know much about them, I took it thinking it was a good idea when in reality I've only had it out twice.

Starts off the button, although The battery isn't the greatest and it loses its charge after a few weeks. It goes through all the gears, the only issue I found is I couldn't knock it into neutral without switching the engine off. This may be a quad issue or simply the fact I genuinely have zero clue what I'm doing with it. Apparently it's had alot of money spent on it from the previous owner but there is no paperwork to prove but I'm sure anyone who knows about these will look at it and make their own mind up.

I'd be open to alot of swaps, although I'd be more interested in a good quad that suits a 12 year old or perhaps a decent t project car that I can work on with my boy?

I have cash I could add to the right deal, also I'd accept cash for the right deal.

NOTE... as much as I say I dont know much about quads I do know you'd struggle to buy one of these period, I also know it isn't 7 or 800 pounds worth so please be sensible with your offers