How To Clean Up Handlebar Wiring on Your Motorcycle

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How to clean up handlebar wiring on your motorcycle
Replacing the stock Kawasaki Vulcan 1500 Classic handlebar clamps with Cobra’s bridge-type billet item reinforces the center handlebar area, helping to prevent it from cracking if a hole is drilled to route handlebar wiring. With the dual-clamp arrangement, the bar pivots very slightly at each clamp point, putting bending pressures at the middle of the bar. That can lead to a fracture if you drill a hole in the center of the handlebar.Cruiser

If you have looked at the wiring running from your handlebar switches and been annoyed by the clutter, you're not alone. A customizer looking to clean up the appearance of his bike will focus on this blemish sooner or later. Once you have replaced hoses and cables with pretty aftermarket items, the switch wiring may stand out like a wart, begging for attention.

If you inspect the creations of professional builders such as Denny Berg (Get some of Denny's customizing tips HERE), you will often find that they relocate or remove most of the handlebar switches. Berg is fond of using microswitches in the ends of the handlebar for horn and starter buttons. A starter button may also be incorporated into other fixtures—the middle of the steering stem, on a dash, to the top triple clamp, etc.—since it's usually not needed in a hurry while riding. For builders willing to give up practicality, every switch can be put wherever it looks good or (in the case of a kill switch, for example) simply eliminated. By moving the switches from the handlebar, you not only eliminate the wiring running down the handlebar, you eliminate the need for the ugly switch housings, though on most bikes you will have to buy a new throttle assembly.

What if you want to keep those smooth-working, accessible handlebar switches? Why not chrome the housings and route the wiring out of sight inside the handlebar? On most bikes, the basic procedure is not too difficult, provided there is nothing large and solid (such as a weight) in the part of the bar through which you want to run the wiring. (In that case, you will need to buy a new handlebar.) At each side of the bar, drill a hole big enough for the wiring emerging from the switch housing at a point which will be covered by the switch housing and where the wire can be directed without pinching it. Drill another hole, perhaps an oval, in the middle of the bar where both looms can exit. Then, using a hanger or a length of welding rod, snag the wire loom and pull it through.

Unfortunately, it isn’t quite that simple. Those holes, especially the one in the middle, significantly weaken the bar. It used to be common practice for the factories to route the handlebar wiring inside the bar. The reason that it’s not done anymore is due to safety concerns, not cost.

To understand the danger, you need to look at the forces exerted on a handlebar. Most one-piece tubular handlebars, such as those used on virtually all cruisers, mount to clamps fastened to the top triple clamp with a single bolt each. With the handlebar removed, these clamps can pivot. As the rider puts pressure on the ends of the handlebar under braking and acceleration, the mounts still try to pivot, bending the handlebar in its middle very slightly. If the clamps mount in rubber, there is even more latitude for movement. This causes a minute flexing in the center of the bar. With a hole drilled in the middle of the bar, the bending forces concentrate there, in time causing cracks to develop. These soon turn into a fracture. One day you hit the brakes and both handlebar ends move forward, pivoting around the mounts.

So, if you are going to route wiring inside the bar this way, you need to be aware of this problem. To ensure that the handlebar does not break, the area between the handlebar clamps must be reinforced. A few handlebars come with a reinforcement welded to this area, but you can add it. Slip a larger piece of tubing over the bar, cut it to a length that permits it to fit snugly between the clamps, weld it in place, and chrome the final result. If this is not practicable, buy or machine a handlebar clamp arrangement that bridges the two clamps.

To further ensure the handlebar doesn’t crack at this or other points where you have drilled holes, keep the holes as small as possible, and dress the edges of the holes so cracks don’t develop. If you are relocating some of the switches, you may be able to get by with very small holes. If you are changing the handlebar on a bike with the wiring routed inside the bar, be certain that the replacement bar is as strong as the one it replaces. If the bike falls onto the handlebar end, check around the holes for cracks.

We tend to take handlebars for granted, and generally we can get away with it, but they are a critical component. If they break, you lose your primary control-link to the motorcycle.

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