Good news for your knuckles: the S50’s battery drops out the bottom of the box ahead of the rear wheel. No seat removal. No interpretive yoga with side covers. Just a tidy little trapdoor operation with the right order of operations.
What You’ll Need
- 10 mm socket or wrench
- Needle-nose pliers
- Dielectric grease (optional)
- Replacement battery sized to UB16B-A1 (confirm fit and orientation on Partzilla’s S50 battery diagram)
Want a quick visual of the bottom-door approach? These rider notes and threads line up with the S50/S83/VS800 family’s under-bike battery design: 2005 S50 battery change (video), 2005 S83 battery removal (bottom door swings down), VS800/S50 clearance tip: roll rear wheel onto a board, and S50 bottom plate drops — remove side bolts and pull down. If you misplaced the trapdoor screws, one rider documented the OEM size from the parts fiche: M5×8 panhead screws reference.
Safety (the short chant you’ll remember)
Ignition off, key out. Work in a ventilated area. Negative (–) off first, negative on last. No exceptions.
The Correct Bottom-Exit Steps
1) Make space under the bike. Put the bike on its sidestand on level ground. For extra clearance, roll the rear tire onto a 2×4 (or similar). This nudges the battery box a little farther from the floor, making the trapdoor and battery easier to wrangle (see the board tip in this forum note).
2) Locate the battery box trapdoor. It’s in front of the rear wheel, centered under the bike. You’ll see the small bottom plate (“door”) secured by a screw on each side, depending on year/hardware (the parts diagram on Partzilla helps you positively ID the bits).
3) Support the battery, then remove the trapdoor screws. Place one hand or a small jack/wood block under the door to support the battery weight. Remove the trapdoor fasteners (common spec reported: M5×8 panhead; see bolt reference). Swing the bottom plate downward. The battery will lower just enough to give you access to the terminals.
4) Disconnect the terminals with the battery partly lowered. With the battery supported, loosen and remove the negative (–) cable first, then the positive (+). Keep a thumb over the tiny square nuts in the terminals so they don’t BASE-jump into the subframe. Tuck the cables aside so they can’t spring back to the posts.
Ah, yes — those leads. Suzuki really tested the limits of human dexterity there. The terminals on the S50’s battery sit deep in a narrow pocket, surrounded by frame rails and wiring that seem actively hostile to tools. A full-size ratchet is about as useful as a turkey leg in that gap. What you actually need is a mini 10 mm tool setup: a ¼-inch drive flex-head ratchet or a tiny right-angle wrench paired with a shallow 10 mm socket. Even better, slip the socket onto a thumb ratchet or bit ratchet — something barely longer than a matchbook — so you can turn it one or two clicks at a time without scraping knuckles on the frame. Magnetic sockets help too; those square terminal nuts are Houdini-level escape artists. Some riders even use a 10 mm wrench cut down to half-length just for this task. Whatever you choose, you’ll feel like a surgeon operating through keyhole incisions — and when that negative lead finally comes free, you’ll want to stand up and take a bow.
5) Drop and remove the battery. Lower the battery the rest of the way and slide it out through the bottom. If it snags, check for any harness that might be catching. Some riders find a gentle wiggle plus the 2×4 trick makes it glide (the “door swings open” method is echoed in this S83 post and this S50 thread).
6) Prep the new battery. For flooded UB16B-A1 types, fill and charge per instructions before install. For AGM/LiFePO₄, ensure it’s fully charged and oriented correctly (posts to the proper sides). A light smear of dielectric grease on terminal faces helps deter corrosion.
7) Reinstall from the bottom and secure the door. Slide the new battery up into the box. Reconnect positive (+) first, then negative (–). Confirm the lugs lie flat and don’t rotate when snugging. Swing the trapdoor back up and reinstall its screws to snug (do not over-torque small fasteners). If you borrowed the 2×4 trick, roll back off and verify nothing rubs.
8) Test and tidy. Key on, neutral light bright, press starter. You want crisp cranking. If it hesitates, recheck terminal tightness and battery state. When routing looks dubious, sanity-check against Partzilla’s diagram or watch the bottom-access video once more.
Troubleshooting (fast)
- Click but no spin: Battery low or poor terminal contact — clean, re-snug, retest.
- Dead silence: Verify kill switch, main fuse near starter relay, and that negative landed on bare metal.
- Weird intermittent resets: Those square nuts can sit crooked; re-seat so the lug clamps flat.
Art Prompt (Cubism)
A fractured still life bursts across the canvas: a guitar neck, a wine bottle, and a folded newspaper reduced to interlocking planes of ochre, slate blue, and warm charcoal. Edges collide at sharp angles, creating a mosaic of light and shadow where wood grain becomes geometry and glass becomes faceted moonlight. Forms overlap in a shallow stage, textures of stippled pigment and matte paper collage peeking through. The composition leans diagonally, dynamic yet balanced, with crisp contours and subtle gradients that nudge the eye in zigzags. The mood is urbane and slightly enigmatic — like café chatter rendered into prisms — its cubed echoes humming with quiet sophistication.
Video Prompt
Begin with a tight macro on a single angular plane, then whip-pan to reveal the full cubist tableau. Animate the guitar strings as vibrating lines that ripple into geometric waves; let the bottle’s highlights shard into moving facets. Use gentle parallax so overlapping shapes slide past each other, as if the canvas were a city of planes at rush hour. Cut on beat to quick jump-zooms through negative space, then drift into a slow orbit where shadows deepen to charcoal. Finish by reassembling the scene from fragments — pieces fly in from the edges and click into a final, satisfying lock — before a soft vignette fade.
Songs to set the mood:
- Liszt — Bonobo
- Wolf Like Me — TV on the Radio
If this helped your Boulevard behave, drop a comment with your battery brand and any trapdoor tricks you found. Follow for more ride-saving fixes delivered with fewer sparks and more smiles.