Yamaha Tri-moto mods

[Yamadog]

I am about to buy a Yamaha tri-moto that is in excellent stock condition. I would like to make the machine a little more stable. Do they make a wider axle for these machines and how much should I expect to spend? Currently the bike sits on 3 uniform balloon tires. What is a good combination of size and tread pattern for medium to hard dirt? The current owner my neighbor is in CA for a week. I am not sure what year it is and I think it is a 200 cc bike.
Thanks

[Trikeaholic]

I have a set of axle extenders for yamaha pattern rims, Im not sure I want to sell them, but I might. I had a buddy make me some new ones for Honda bolt pattern so the Yamaha ones just sit on the shelf.

[plkmonster2]

3 or 4 bolt?