Welcome back to Iconic Motorbikes’ Iconic Restoration Tips! Since our last post, Iconic Motorbikes’ resident mad scientist has been hard at work in the lab, working on new restoration tricks! When we left off, our yellowed fluid reservoirs had been returned to like-new condition, but the caps had been set aside for a future post.
This post, in fact.
Those caps, along with many other plastic and synthetic rubber components found on both vintage and modern bikes, can be easily restored using a process I refer to as “re-moisturization,” a little trick learned years ago from a professional research chemist. To demonstrate, we will use the cap from the previous brake fluid reservoir restoration post, along with the rear hugger from a 1995 Kawasaki ZX-7R.
For those of you who aren’t professional research chemists, I’ll try to keep things relatively simple. The vast majority of plastic parts used on our motorcycles are molded using polyvinyl chloride or “PVC” plastic. The science behind its restoration begins with understanding the chemical composition of PVC. Vinyl chloride monomer or “VCM” is formed by combining ethylene (obtained from petroleum) with chlorine (produced from the electrolysis of salt water). VCM molecules are polymerized to form PVC resin, and appropriate additives are incorporated to make a customized PVC compound with characteristics specific to the part’s intended function.
The key to this lies in the ethylene, which is the primary component in PVC plastic. Over time, and with exposure to environmental chemicals, heat and the UV rays of the sun, PVC-based plastics tend to dry out, lose their moisture and luster, and become brittle. Fortunately, ethylene is derived from petroleum, and there are many products on the market that are advertised as being able to “restore” black plastic:
However, these products primarily contain “petroleum distillates,” and their petroleum content is not nearly enough to properly restore these damaged parts. The process of re-moisturization solves this easily and inexpensively by using a different product:
The sophisticated technique for re-moisturizing parts? Simply slather a generous amount of petroleum jelly onto the parts using a clean shop rag as shown:
Once applied, let the petroleum jelly soak into your parts for a minimum of 48 hours. Then simply wipe it off and buff the part with a clean microfiber towel. The results of the re-moisturization process are remarkable:
This same re-moisturization process can be used on the synthetic rubber motorcycle parts:
Once again, the results are impressive. Plastic and synthetic rubber parts are soft, pliable, and ready to go back on the bike!
That’s it from the Iconic Restoration Tips for now, so stay tuned for our next installment!