initial meeting with Kofi, I expressed concern whether the proximity of the cat covers to the exhaust system and its associated heat would cause a problem for the carbon fiber overlays. Kofi did not perceive it to be an issue, but reminded me that my project is virgin territory for him. After subse- quent research in the area of heat conduction, I decided upon titanium and stainless steel fasteners, as both metals tend to be poor conductors of heat. And I found that a titanium Torx T25 button head cap screw used in conjunction with a # 10 stainless steel washer nicely replicates the look of the OEM fastener. I replaced the stock cat covers with
the carbon fiber ones and was pleased to see that the lines in my bike again flowed. The transformation is noth- ing short of amazing. My new cat covers match perfectly in pattern and finish with their Akrapovic carbon fiber mates. But I knew that the true test would be in the ride—whether the overlaid cat covers would hold up to the heat of the exhaust system. I immediately geared up and headed out for a test ride, with a stop at one of the local BMW dealerships to show off my K 1600 GT’s new look. About 50 miles and an hour later, I was back in my garage, eager to see how the cat covers had fared. To my dismay, I could see what appeared to be a silver ring that had formed at the outer edge of one of the fasteners. A closer inspection of that mounting hole revealed that the bare metal of the cat cover was now exposed at the outer rim of the stainless steel washer used with the titanium screw. Inspection of the other three mounting holes also revealed signs of distress to the carbon fiber overlays. There now appeared cuts, cracks
and crevices in the once pristine car- bon fiber. All damage was confined to the immediate area surrounding the mounting holes—the rest of the car- bon fiber overlays remain perfect.
58 BMW OWNERS NEWS May 2016
I thereupon sent Kofi an email message,
complete with pics of the now-damaged areas, and requested his thoughts on the matter. I also inquired if and how a remedy could be effected. Kofi, after consultation with his fabricator, replied that the heat generated by the exhaust system likely transferred to the fasteners and corre- spondingly caused shrinkage at points of contact and the noted damage to the carbon fiber overlays. He also told me that it was an easy fix, and requested that I return the cat covers to him. I did so, and within about a week’s time, was again meeting with Kofi to pick up my repaired cat covers. Upon inspection, I could tell that the cat covers had suffered repairs to the areas surround- ing the mounting holes, and, though acceptable to me, they are no longer the perfect cat covers that I had initially installed on my bike. The repairs were done at no charge to me, and Kofi and I chalked the initial installation up to a learning expe- rience. But now it was time to get it right. Back to the internet I went, this time con-
centrating on ways to adequately buffer heat transfer from metals. I learned PTFE (Teflon) to be such a buffer, and it is rou- tinely used in high-temperature applica- tions. I also took a close look at the fasteners used by Akrapovic in fitting its carbon fiber accent pieces to my silencers and noted what appeared to be non-metallic (likely Teflon) washers directly beneath the screw caps. During my internet searches I also learned that attaching carbon fiber prod- ucts to any surface should be done with care, using fastening techniques that dis- perse the stress caused to the carbon fiber at time of installation. Armed with this new knowledge, I procured Teflon washers of the appropriate inner and outer diameters, and even found carbon fiber washers of an outer diameter that would cover all signs of repair to the cat covers, yet look natural to the installation. Using a combination of stainless steel,
Teflon, and carbon fiber washers, I devised an order to fastening the cat covers that hopefully would not only minimize if not eliminate the transfer of heat to the carbon fiber overlays, but also adequately disperse
any stress to the overlays caused by the fas- teners. Moreover, the ordering visually appeared natural to me—like it was sup- posed to look that way. I re-installed the carbon fiber cat covers using my newly- devised fastening sequence and was happy to see that I had hit my mark, at least as per- tains to the visual aspect of the installation. But, again, the proof of my success would
be in the ride. I thereupon embarked on a similar ride to that taken after initial instal- lation, but this time more anxious in the return to my garage. Upon dismount, I thoroughly inspected each mounting hole and found no signs of distress to the carbon fiber overlays. Nor have any subsequent rides produced any such signs. Feeling a sense of both relief and accomplishment, I am at the point now where I inspect the cat covers only when I check the air pressures in my tires. Fueled by the look of the carbon fiber cat
covers at first view, I knew that I would want to overlay with carbon fiber other parts to my bike. I intently surveyed my K 1600 GT, looking for areas that would ben- efit from carbon fiber, yet not overwhelm the bike. I ultimately decided to overlay with carbon fiber those parts on my GT which come as standard in chrome on the K 1600 GTL. Such a venture would produce a nice bridge between the K 1600 GT and K 1600 GTL, while complimenting the car- bon fiber already existing on my bike. I chose to start with the windshield trim pieces, and again Koncept Cars did not dis- appoint. But because of the small and deep recesses in the area of the mounting holes, the fabricator had a difficult time produc- ing perfect carbon fiber overlays to those recesses. I was not overly concerned, because I knew that I now had an array of suitable washers on which to draw to con- ceal the defects. Using a combination of stainless steel and carbon fiber washers, I was able to fill the recesses and produce a finished look to the installed carbon fiber windshield trim pieces. Any imperfections are now covered, and the fasteners virtually take on an OE. look. A knowledgeable pur- ist would have to be looking closely to notice the difference.
TECH
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