I found these two products that remove powder coat and also anodized finishes. Two finishes that are used on the harleys.

These are hard to remove finishes unless professionally done.

Hope you find them useful.

Anodized finish remover..
Eastwood Co. - Eastwood Anodize Remover 16 oz Trigger style Spray (http://www.eastwoodco.com/jump.jsp?itemID=18807&itemType=PRODUCT)

Powder coat finish remover..
Eastwood Co. - Eastwood Powder Coat & Paint Dissolver Quart (http://www.eastwoodco.com/jump.jsp?itemID=16495&itemType=PRODUCT)