If you're aiming for that ultra-clean cockpit look on your bike, drilling handlebars for internal wiring is pretty much the best way to make it happen. There's something deeply satisfying about seeing a set of bars with zero visible clutter—no zip ties, no plastic sheathing, just clean metal lines. But let's be honest, the thought of taking a power drill to a perfectly good set of handlebars can be a bit nerve-wracking. You're intentionally putting holes in the thing that helps you steer, so you definitely want to get it right the first time.
Most riders go this route when they're building a custom bobber, a chopper, or even just cleaning up a modern cruiser. It's one of those "pro-level" mods that isn't actually that hard if you have a steady hand and a little patience. In this post, we're going to walk through how to handle the job without ruining your bars or compromising your safety.
Is your handlebar a good candidate?
Before you even touch a drill, you've got to look at what you're working with. Not all handlebars are created equal. If you're rocking thin-walled, cheap aluminum bars, you might want to think twice. Aluminum can be finicky; once you compromise the structure with a hole, it can develop stress cracks faster than steel.
Steel bars, on the other hand, are the go-to for this kind of project. They're sturdy, forgiving, and can handle a few well-placed holes without turning into a safety hazard. You also need to consider the diameter. If you're trying to shove a thick bundle of wires through 7/8-inch bars, it's going to be a tight squeeze. 1-inch or 1.25-inch bars are much friendlier for internal routing because they give you some literal breathing room.
Gathering the right tools
You don't need a full machine shop, but a few specific tools will make this a whole lot easier. You'll want a good power drill—corded is usually better for consistent torque, but a strong cordless one works too.
You're also going to need: * A center punch (this is non-negotiable) * High-quality cobalt or titanium drill bits * A small round file or a deburring tool * Masking tape * A permanent marker * Cutting oil (to keep those bits from dulling)
The center punch is probably the most important tool here. If you try to drill into a curved chrome surface without a pilot dimple, that drill bit is going to dance all over your bars, leaving some nasty scratches behind.
Marking your territory
Don't just start drilling where you think the holes should go. Mount the bars on the bike first. Sit in the saddle and see where your hands naturally fall. You'll want the entry holes near the switch housings and the exit hole usually right in the center, between the risers.
Once you've found the spots, wrap the area in masking tape. This does two things: it gives you a surface to draw on, and it protects the chrome or powder coat from any minor slips. Mark your exact center points with a marker, then give that center punch a good whack with a hammer. You want a deep enough divot that the drill bit has no choice but to stay put.
The actual drilling process
Now for the part that makes everyone sweat. Start with a small pilot hole. Don't go straight for the final size. A tiny 1/8-inch bit will catch much easier and give you a guide for the larger bits. Apply a drop of cutting oil and go slow. You don't need high speed; you need steady pressure.
Once the pilot hole is through, move up in sizes incrementally. If you need a 3/8-inch hole for your wire loom, don't jump from 1/8 to 3/8. Hit a 1/4-inch bit in between. This keeps the heat down and ensures the hole stays round.
Pro tip: If you're drilling the center exit hole, sometimes it's better to make it slightly oval or "slot-shaped" rather than a perfect circle. Wires don't like 90-degree bends. An elongated hole allows the wires to exit at a more natural angle, which prevents the insulation from chafing over time.
Smoothing things out
This is the step most people skip, and it's the one that causes the most headaches later. Once the holes are drilled, the edges inside the bar are going to be sharp—like, razor-sharp. If you pull your wires through those raw edges, the metal will slice right through the insulation, and you'll end up with a short circuit the first time you hit a bump.
Take a small round needle file or a deburring bit on a Dremel and smooth out every single edge. You want it to feel like butter when you run your finger over it. If it's still catchy, keep filing. After that, it's a great idea to use rubber grommets in the holes. If the holes are too small for grommets, at least use some heavy-duty heat shrink tubing over the wire bundle where it passes through the metal.
Fishing the wires
Honestly, drilling handlebars for internal wiring is the easy part. Getting the wires through the bars is where the real test of character begins. You aren't going to be able to just push the wires through; they'll bunch up and get stuck at the first corner.
The old-school trick is to use a piece of string and a vacuum cleaner. Plug one end of the bar, put the vacuum hose over the center exit hole, and feed the string into the entry hole. The vacuum will suck the string right through. Once the string is through, tie it to your wire bundle and pull it back.
Another way is using a thin "fish tape" or even a piece of stiff baling wire with a small hook on the end. Just be patient. If you feel resistance, don't just yank. Pull it back a bit, wiggle it, and try again. Using a little bit of wire lube or even just some dish soap can help the bundle slide through the tight spots.
Structural integrity and safety
I'd be remiss if I didn't mention the "don'ts." Never drill a hole right next to a weld or a sharp bend. These areas are already under stress, and adding a hole there is just asking for a handlebar failure. Try to keep your holes at least an inch or two away from any structural joints or the clamping area of the risers.
Also, keep the holes as small as possible. You only need enough room for the wires to pass through comfortably. A massive gaping hole might look easy to work with, but it significantly weakens the tubing. If you're worried about the strength, you can sometimes weld a small "bung" or reinforcement ring around the hole, though that's usually overkill for most street bikes.
Wrapping it up
At the end of the day, taking the time to do this right transforms the look of your bike. It's one of those subtle mods that people notice without really knowing why the bike looks so good. It just looks intentional and high-end.
Just remember: measure three times, punch your centers, start with small bits, and for the love of all things holy, deburr those holes. Once you get those wires tucked away and your switch housings bolted back on, you'll realize the effort was totally worth it. There's nothing quite like the view from the seat when all you see is the road ahead and a clean set of bars. Happy wrenching!