I know to most of you , this is a stupid question, but I picked up this Power King 3 speed (Made in Japan) and it was missing the seat post tube bolt, so I thought all I had to do is insert a bolt and tighten it up. As you can see in the pictures, there is no slot in the seat post tube to collapse with the bolt tightened. How do you tighten this seat post in the seat post tube? Thank you