ICE bikes too…
In speaking with other ICE bike dual sport owners I have found that they too have had issues with failing rear turn/tail light assemblies. As a matter of fact they make it sound as if it’s a common occurrence. KTM, Suzuki specifically. Some of that makes me feel better, but another part of me isn’t comforted. When I began racing a very wise racer with way more experience told me “Mark, always look at how clean someone’s bike is when they arrive at the track. If their bike is dirty you can be almost certain that they do not regularly check things on their ride. Just my two cents but I’ve found this to be true in my racing career.”
Sure enough when I began road racing my teammates were meticulous about their bikes. It taught me that checking/marking bolts, fasteners, etc. not only prevented DNFs but more importantly crashes. As I was inspecting my Kalk (LOL) I noticed a small chip on the top left side of my swingarm. It occurred to me that when my tail assembly mount failed and I noticed the assembly flash by me to my left side; the reason it was thrown forward was due to the wiring created a pendulum and as the assembly hit my rear tire it was thrown forward. So I started thinking that “if” the assembly had been thrown on the right side of the bike and jammed into the chain/sprocket I “could have” been thrown forward off the bike at 59 MPH! All of this is of course “Shoulda, Coulda, Woulda” stuff but…
In addition to reinforcing the rear bracket brace as described below I decided to design a tether so that if the brace does fail the rear assembly will not drop into the tire/sprocket/chain. I guess it’s just my own paranoia having crashed on the racetrack several times, once due to an equipment failure of my front magnesium rim where it disintegrated. So I zip tied the horizontal bar of the turn indicators to the upper two extension bars of the section that extends under the seat. The most valuable lesson I learned from road racing is all of the precautions taken like using Water Wetter rather than slick as KY Jelly radiator coolant, safety wiring drain plugs/caliper bolts is all about ensuring the safety of others. Old great habits never die, they’re just transferred to new adventures.
Other’s have experienced this part failure
Cake US informed me (which is admirable to me) that two other USA Kalk& customers have had the same failure of the license plate/rear turn signal mount. They let me know that Cake Sweden is revising the design of the part at the urging of Cake USA. Further down in this post you will see the part that failed. After further examination of the part I surmise that it was caused by vibration fatigue.
What I initially believed was a delamination of the metal upon closer examination the part failure shows the characteristics of vibration fatigue. Because the license plate catches the wind as the bike moves and vibrates, and since the aluminum bar is only 2.45mm thick the part does not appear strong enough at sustained high speeds. Which is what the &’s do on roadways. Cake USA let me know that the primary goal of the Swedish design is to keep the bike light. I know this phenomenon well since during my backpacking days I would literally drill holes in the handle of my toothbrush to save grams! But there is always a tradeoff (you never get something for nothing) with weight savings; a loss of strength depending on the design and use of the part. When I was a young teen we use to use metal coat hangers to roast marshmallows at the beach. We found that if we kept rapidly bending the metal back and forth at the junction it would heat up. So much so we use to burn one another with those things; Ah The Good Old Days! LOL. A classic example of vibration fatigue.
I was told by Cake USA that the part’s redesign will be accomplished in “spring of 2021” which for me is too long to wait. Why? Well because experiencing this failure, fortunate enough in noticing that the assembly had fallen off of my bike, not having it caught in my sprocket/chain, not losing my CA license plate – I do NOT want this to happen again. And waiting until Spring 2021 is too long. I ride my bike because where I live I don’t have an ‘off season’ in winter. Not to mention that as a motorcycle rider one of the worst things that can happen on the street is when something falls off a vehicle in front of you! I don’t want to be THAT GUY.
So here is what I did….
Reinforcing the rear tail mount
I disassembled the new replacement rear section and Dremel’d out the bottom of the tail light so that I could install a 3.2mm aluminum bar stock bent to the same angle as the rear assembly. I then bolted it to the right hand side of the tail assembly to prevent vibration failure. It took some planning to ensure that it would not interfere with the OEM assembly. But for ME it’s well worth the hassle to prevent another part failure. The part did not fail at the bend, but where the narrow portion of the mount meets the wider upper portion of the tail light assembly. So the leverage of the lower section combined with the surface area of my license plate caused random vibration which is classic in vibration failure cases.
I revised my original fix by using 2mm thick stainless steel and opted to make the reinforcement the entire width of the license plate hanger rather than just on the right side. I also epoxied the metal brace to the aluminum hanger and bolted it at the top as well as with the turn signal mounting bolts. And I decided to spray dipped the assembly to prevent rust of the steel plate.
My first fix:
Cake’s quick replacement part turn around
It is at this point I want to state that both Nate and Emily from the SLC Cake office took care of sending me a replacement rear light assembly right away. I was planning to be out of town so they kindly arranged to have my part FedEx’d to me to arrive close to my return home. Wonderful customer service as I’ve come to experience with Cake.
I sincerely hope that when Cake Sweden revises the part they retroactively ship them out to Kalk&/INK& owners so we can replace the parts to prevent what happened to me and others. It’s not only a safety issue to Kalk/INK& owners, but to the driving public.
How it occurred
Today on my way home I took a road where the speed limit is 45 MPH. Of course no one travels at that speed and that includes me. I had the throttled pinned and was maintaining 59 MPH just to stay with the flow of traffic.
Out of the corner of my eye I see ‘this thing’ as it bounces by me and then behind me. So at the first opportunity, I pulled over on a side street to inspect my bike since I just recently installed a Red Light Magnet on the bottom of my bike and thought it may have fallen off. Nope it was still there. As I began to look around I noticed something strange, no license plate or rear turn signals! WTF!!!!
I then rode to the other side of the highway did a U turn and retraced my route, I saw my plate and turn signal assembly on the side of the road. I pulled over as far as I could on the street and walked back to grab my plate. I have installed a license plate locker on my bike and it was open since the lock was broken on impact with the ground and the contents were gone. In it I kept:
- My CA registration
- My Proof of Insurance
- One COVID19 paper mask
I walked back for about ¼ mile hoping to find my paperwork, no luck. Luckily I keep a tank bag on my bike that has bungees on the top so I was able to lash the part to my tank bag and rode home. When I got home I disassembled the rear light assembly and began to examine the metal portion that failed on the license plate holder.
At no time during my ownership has that area sustained impact of any kind. Actually nothing on the bike has sustained any impact. And after examining the metal it’s obvious that there was no curling or deformation of the part which would indicate some sort of prior impact. But what I did notice is the delamination of the metal bar on the portion that holds the plate to Cake’s rear tail light assembly.
You can see there is no curling of this piece which is the portion that holds the turn indicators that hit the ground. It is very apparent that the metal has delaminated.
This is the portion that remained on the bike, the tail/brake light portion. The delamination of the metal here is even more apparent than in the prior image.
I wondered if the license plate locker put added stress on the metal so I weighed the locker and the license plate.
A 3.78 ounce delta between my license plate and the license plate locker does not seem enough to stress the metal mount enough even with the small items I had in the locker for it to fail. Also the surface area of the locker and license plate is very similar so I do not believe that any added wind resistance would cause the issue.
I am submitting this to Cake as a warranty claim since it seems to be a failure in materials. Once I find out what will happen I will update this post.