My daughter has a 1998 xr70. I just ordered a 22mm carb from ebay thinking this was the stock size. Further research has indicated that this is not the stock size. 1. will this carb work on a stock 1998 xr70? 2. what modifications are needed to make this 22mm carb work on a stock 1998 xr70? 3. if this is not the stock size, why do I see so many for sale and not oter sizes?