Welcome to SaleHoo :) Nice to have you with us!
Maybe you could provide us a link to one of your existing listings for your motorcycle so we can have look at it and hopefully provide you with constructive criticism to help you finally sell it!
To add a product, kindly login to your SaleHoo Store admin site and go to
Products > Products (stay on the Products page, don't go to Download) and click on the "Add New" button on the upper right corner. And you should be able to add new products to your store.:)
Here is a video guide to help you - Link hidden: Login to view
The video also explains clearly what the Download tab is for. :)
Hope this helps.