Friday, March 3, 2017

WR250R tail tidy, the hard way

Honda and Yamaha have a knack for designing rear fenders that look like the spawn of Jar Jar Binks mated with an escalator:


On second thought, it looks more like Princess Leia when she snuck into Jabba the Hutt's lair:


Unfortunately, the WRR fender tangles with your body and scenery precisely how most princesses would not:



After slicing myself on the license plate yet again, it was the last straw and time to relocate the plate to a better position. Unfortunately, Ontario Regulations on motorcycle safety inspections suggests that installing some of the more popular aftermarket tail tidy kits I found for the WRR could risk a ticket. On the other hand, Regulation 1. (3) states: "No part of the motorcycle shall have a broken, bent or sharp edge that protrudes in such as way as to constitute a hazard to persons or vehicles."

This seemed to be a good enough justification for moving the plate. And the Edge 2 tail tidy kit ($121.99 at Kimpex, the cheapest option I found), which relocates the plate higher and incorporates a new tail light, looked like the best way to do it. However, because I'm cheap, I wanted to reuse the original Yamaha Jar-Jar-eyes turn signals. I also wanted to retain the three reflectors to hopefully avoid other regulatory problems. So, some mods were in order to fit everything together with the Edge kit. The result was a disproportionately epic project that provided several nights of entertaining fabrication, using stuff around my shop.

My concept was to make a C-shaped bracket that bolts onto the Edge 2 where some optional LED signals are intended to mount. The first step was to create a pattern, with the dotted lines indicating where I'd bend the material at right angles.


Here it is transferred to some 3/16" T6061 plate aluminum I had on hand and cut out with a jigsaw. Some filing cleaned it up. 


I scanned the part and can send you the PDF if you want a starting point to make your own.

The teardrop-shaped holes are for the rubber bases of the signals, which just press in and are held in place by friction and a moulded lip. The small end of the teardrop should face forward; I ended up flipping the bracket around to get the right fit which required reversing the hole orientation. 

Ignoring all common sense and my experience with material properties, I then stupidly tried to bend the ears 90 degrees to form the bracket. Oh snap.


Vincent van Gogh would've appreciated my craftsmanship. I decided to cut off the other ear as well so at least the problem was symmetrical. Then some extruded aluminum angle I had lying around inspired the idea of making some corner brackets to reattach both ears. 


The brackets were cut oversize to make alignment easier, then drilled, epoxied, and riveted in place. 


After filing them back to the original profile, they looked OK. 


Since the extrusion was fairly thin and I didn't want it cracking when the signals got hit in a fall, I added some JB Weld to fillet the inside corner. The result was pretty solid:


Black paint does marvels to cover imperfections:



While the paint was drying, I mounted the tail-light and connected the wiring. Here's the original harness under the left body panel:


The original fender used separate wire bundles for the tail light (3 wires; big white plug) and plate illumination light (2 wires; yellow plug). Since the Edge integrates the plate lights with the brake lights, it needs just three wires which connect to the original brake light plug. I cut off the mating plug from the original fender wiring harness and soldered/heat-shrunk it to the new Edge cable so I could just plug it in to the existing harness. The yellow plug (for the plate light) on the bike is no longer needed, so I just wrapped it with electrical tape to keep it clean.

Lights worked fine. Although the taillight is smaller than the original LED unit, it's quite bright and almost painfully so when the brakes are on. The plate illumination is also plenty bright.
    

Now back to the bracket. The tail lights squeezed in quite solidly.


Assembly with the Edge bracket proved a little tight, so some minor filing was needed to fit everything together. Although not shown here, I found I needed to bend the signal mounting tabs on the Edge so that when I mounted my bracket, the signal lights aimed horizontally and not up.

Here's the wiring routed to avoid interference with the mount points for my custom rear rack.


Here's a simple bracket I made from some stainless steel salvaged from a dishwasher door, to mount a rear-facing reflector under the plate. There's a subtle notch filed into the side of the bracket that locks with the anti-rotation pin on the reflector.



The Edge 2 kit comes with some small steel angle-brackets (not shown) for mounting after-market LED turn signals. The brackets are just the right size for mounting the side reflectors to the license plate bolts.

Here's the finished assembly.


It's a much cleaner look with more clearance than the stock fender.


It also shaves off nearly a kilogram from the stock configuration, in a location where loads adversely affect handling. Overall a win and I'm looking forward to testing it on the road.

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