Has any one has built or had experice building a older ariens yt10?

hello i was wondering if any one has built or had experice building a ariens yt10 its a older one it has a 3 speed with a hi and lo so i guess you would call it a 6 speed i have locked the rear and put some nobby tires on it the rear pulley was a 5 inch i put a 4 inch on it and if any one has seen these mowers they know that the belt from the moter goes to a jack shaft from the factory and then from the jack shaft to the rear where the clutch and rear end pulley but the jack shaft sits off to the side and unfortantly the pulley on the jack shaft is small i would say that the pulley that the moter is hooked to is a 4 inch and the one that runs the rear is a 2 and half but with it sitting off to the side the smaller pulley the belt only touches not even a 3rd of that pulley and it slips bad and i wanting to know is it hard to convert it to one belt or is there other pulleys i can buy but i would rather convert it any help would be appreactated