AMF Harley-Davidson X-90 (MiniBike) Page 2 of 2

This page is about the front forks...

As I do not know about drawings for the different front forks used on the X-90 and because it is not listed in the X-90 parts manual, but only in the supplement without any drawings I decided to make this page!

Three different front forks were used on the X-90, the early type (Ceriani) is descriped in the parts manual, so the following lines are about the late 1973 to early 1975 front forks: Marzocchi (late 1973 to early 1975) and Betor (late 1975 to end of production).

The Ceriani front fork:

This picture shows the Cerrani front fork.

The 28 mm Marzocchi front fork:

In this picture you can see the fork cup ("1") and the oil seal ("2") which is mounted outside on the lower of the cup. It seals the lower fork legs to the cups. In the line below you can see the ring retainer clip ("3") which holds the two Simmerrings "4" in their position inside the cup. The outside diameter of the ring retainer is 4 cm and the inside diameter is 3,8 cm. The dimensions of the Simmerrings are 28 mm x 38 mm x 7 mm and the originals used by the factory are from Corteco, but you can use others as well, just make sure the outside rim is plain rubber.

To twist the cup out of the lower fork leg, you have to slide the rubber dust cover upward. Use your fingers only, so you don't damage it. Now you have to twist the cup counterclockwise while you are holding the lower fork leg tight. As the cup is made of a soft metal, you should NOT use pliers or anything like that because you possibly damage the cup. A slight deformation and it will not seal the oil properly anymore. In this picture you can see the special pin-tool. If you still can't imagine how to use it, there is another picture.
If you have disassembled the fork and need to refill it, use 150ml of fresh oil

Not yet commented is this picture.

The Betor front fork:

I will report more about this fork in the near future as Bram and Greg already made some pictures for me!

Do you have further information? E-Mail:
Thanks to Bram from Luxembourg for the pictures of the Betor front fork;