YTX9-BS Battery Specifications and Compatibility Guide | 8Ah

The YTX9-BS is a 12-volt, 8 Ah sealed AGM lead-acid battery that fits only vehicles whose manual or parts catalog lists that exact size.

The size code tells you terminal layout and dimensions; it does not promise the electrical performance on Yuasa’s data sheet.

The model number denotes a sealed, maintenance-free AGM (absorbed glass mat) lead-acid battery rated at 12 volts and 8 amp-hours. Yuasa lists 8 Ah at the 10-hour rate and 8.4 Ah at the 20-hour rate, with 135 cold-cranking amps at −18 °C. Calcium/calcium plates and a glass-mat separator hold the electrolyte in place, so there is nothing to top up. Yuasa and Kawasaki both position it as an OEM-size replacement for motorcycles, scooters, ATVs, UTVs, snowmobiles, and personal watercraft, provided the vehicle specifies this size and rating.

What Do The YTX9-BS Specifications Actually Mean?

Three figures decide whether this battery does its job: 12 volts, 8 amp-hours, and 135 cold-cranking amps. The rest describes the case you have to fit.

Yuasa’s UK data sheet lists 152 × 87 × 107 mm and about 3.1 kg with acid, while Yuasa’s 2024 battery application guide lists 150 × 87 × 105 mm and 6.6 lb. That two-millimeter gap is probably a case-height versus overall-height convention, so check clearance against the battery in your hand. The 0.9 A figure is not capacity; it is Yuasa’s recommended bench-charging current, keeping a small AGM case from cooking.

YTX9-BS Battery Compatibility: What Decides The Fit

Your vehicle’s parts catalog decides fit, not the label. A YTX9-BS is correct only when the owner’s manual or a manufacturer’s listing names that size.

Kawasaki sells it as a 12-volt, 8 Ah OEM-style replacement for Kawasaki motorcycles, ATVs, and utility vehicles that specify it, and states plainly that this does not make it universal. The vehicle-specific catalog stays in charge; other manufacturers work the same way, with their fitment charts settling the question.

Cross-reference names on aftermarket boxes include PTR9-BS, M62R9B, 44156, YTR9-BS, EXT9, GTX9-BS, M329BS, 740-1825, 44025, and CTX9-BS. A match is a starting point, not proof: polarity, terminal design, dimensions, and cold-cranking amps must still line up. Our tested YTX9-BS battery roundup separates replacements that hold their rated capacity from the ones that only match the sticker.

Mounting, Polarity, And The Charging Rate

Install the battery upright and centered, confirm polarity in the installed position, and charge at Yuasa’s 0.9 A rate with a charger set for 12-volt AGM lead-acid.

1. Confirm the vehicle manual names YTX9-BS or an exact equivalent.
2. Compare length, width, height, terminal position, polarity, hardware, and hold-down bracket against the old battery.
3. Switch the vehicle off and disconnect the negative cable first.
4. Keep the new battery upright, set it in the tray, and clamp the hold-down so it cannot vibrate.
5. Reconnect the positive cable first and the negative cable last.
6. Charge with an AGM-compatible charger: connect leads before switching on mains power, and switch mains power off before disconnecting.

The job is done when terminals sit flush, cables connect without force, and the hold-down is clamped with no shim needed. Keep flames, sparks, and cigarettes away from a battery on charge. A dry-charged battery sold with separate acid needs the electrolyte absorbed and several hours of charging before installation; factory-activated sealed units skip that.