YTX9-BS Battery: Specs, Fitment, Cross-Reference and Buying Guide
Quick answer:
YTX9-BS is a 12V sealed AGM powersport battery in group size 9. The OEM version is rated 8Ah and 135 CCA, measures roughly 150 × 87 × 105 mm, and carries the positive terminal on the left. It is a direct-fit replacement for Group 9 applications — but not for Group 9B or 9-B, which share a different case.
That one-line answer covers most lookups. The rest of this page covers the details that decide whether the battery actually works in your machine: rating basis, polarity, activation, cross-references, and what to check before you order a pallet of them.
YTX9-BS Specs at a Glance
| Specification | OEM (Yuasa YTX9-BS) | TCS YTX9-BS |
|---|---|---|
| Voltage | 12V | 12V |
| Chemistry | AGM, sealed maintenance-free | AGM, dry charged maintenance-free |
| Group size | 9 | 9 |
| Capacity | 8Ah (10-hour rate) | 9Ah (10-hour rate) |
| Cold Cranking Amps | 135 CCA | Per datasheet |
| Dimensions (L × W × H) | 152 × 87 × 107 mm | 150 × 86 × 105 mm |
| Terminal polarity | + Left / − Right | + / − |
| Weight | ~3.0–3.15 kg, filled | 2.22 kg, dry |
| Activation | Bottle-supplied (fill before use) | Dry charged, electrolyte separate |
| Typical use | Motorcycles, ATVs, UTVs, PWC | Same applications |
Check the test basis behind the capacity figure. The OEM datasheet rates its cell at 8Ah on a 10-hour discharge; the TCS label reads 9Ah/10Hr. Both numbers sit on the same basis, so the gap comes from the manufacturer’s own rating rather than a different test method. Capacity claims do vary between producers, which is why the datasheet — not the headline Ah on a box — is what you should compare.
The weight difference is water. A dry-charged battery ships without electrolyte, so its catalog weight excludes the acid you add at activation. Add roughly 0.6–0.9 kg once filled, and the numbers land in the same range as the OEM unit.
What the Code Tells You
The part number is a spec sheet in miniature.
- YTX identifies the manufacturer’s sealed AGM powersport family — maintenance-free, factory-sealed construction rather than a flooded cell with caps.
- 9 is the group size. Group size fixes the case footprint and terminal geometry. Everything that fits a Group 9 tray shares this number.
- BS indicates a bottle-supplied battery: it ships dry, with an acid pack, and must be filled and charged before first use. Factory-activated versions carry a different suffix.
Knowing the suffix matters in procurement. A dry battery stores longer on the shelf and travels cheaper, but it needs an activation step and a charging bench at the destination. A factory-activated battery arrives ready to install but ages from the day it was filled. Neither is universally better — the right choice depends on your channel and turnover.
One note on naming: YTX9-BS is a part number registered by GS Yuasa, and the YTX / YTZ / GYZ families are their trademarks. Third-party manufacturers publish cross-references to it rather than claiming ownership of the code. TCS supplies a direct-fit Group 9 replacement built to the same case and terminal standard.
Will It Fit? Dimensions, Polarity and the Group 9 Trap
Measure three things before ordering, and check a fourth before installing.
1. Case dimensions
The OEM case runs about 152 × 87 × 107 mm. TCS molds at 150 × 86 × 105 mm. Differences of a millimetre or two are normal, but compression brackets are less forgiving. Measure the old battery with calipers if space is tight.
2. Terminal polarity
OEM layout is positive on the left, negative on the right (viewed from front). Reverse it and cables won’t reach without stretching, which causes fatigue. Confirm your layout, not just the code.
3. Terminal type
Group 9 uses powersport terminals with both top and front connection points. Check which pair your harness uses before assuming either will work.
The trap: Group 9 is not Group 9B or 9-B.
These are different case families that happen to sit in adjacent catalog columns. A Group 9B battery will not substitute for a Group 9 application, and the reverse is equally true. If a listing offers a “9-B” battery as a YTX9-BS replacement, verify the dimensions and terminal positions line by line — the group number alone is not proof.
Cross-Reference: What a YTX9-BS Replaces
Distribution catalogs carry dozens of part numbers for the same physical battery. These are the common equivalents:
| Category | Part numbers |
|---|---|
| Powersport brands | CTX9-BS, GTX9-BS, ETX9-BS, PTX9-BS, UTX9-BS, VTX9-BS, KTX9-BS, FTX9-BS, BTX9-BS, XTAX9-BS |
| Group 9 codes | 9-BS, B106, ETX9, ESTX9, SC9BS, NLP9, PC310 |
| Retail / aftermarket | 44025, 740-1825, AG-901, ATX-9, M329BS, M729BS, MBTX9U |
| European references | Varta 508 012 008, ATH9-12B, B9-12b |
Two cautions when working from a chart like this:
- Cross-reference lists inherit errors: one distributor copies another’s table, and a wrong number propagates for a decade.
- Lithium columns are not drop-in equivalents: A lithium pack sold as “YTX9-BS replacement” may match the case but not the charging behaviour — see the chemistry section below.
For a reseller building a catalog, the practical rule is to verify by measurement and specification against the OEM datasheet, and to keep your own verified table rather than trusting a borrowed one.
Which Machines Use It
Group 9 covers a wide band of mid-size powersport equipment. Kawasaki publishes YTX9-BS fitment across the Ninja 250 and 300, KLX dual-sport and off-road models, Versys, the Z series, and select Brute Force ATVs. The same group appears across Honda, Yamaha, Suzuki, Triumph, KTM and Hyosung applications, plus personal watercraft and snowmobiles that use a Group 9 pack.
Model lists age badly, though. Manufacturers change battery trays mid-generation, and a chart printed three years ago may not cover this year’s model. Search by your exact year, model and engine variant in the OEM application guide, then confirm against the physical battery in the machine. Ten minutes of measurement beats a return shipment.
Signs the Battery Is Actually the Problem
Before replacing, rule out the charging system — otherwise the new battery inherits the old one’s death.
A healthy resting voltage sits around 12.6–12.8V after a few hours off charge. Below 12.4V suggests a partial discharge; below 12.0V under no load points to a failing cell. Cranking voltage tells a more useful story: if it drops below roughly 9.5–10V while the starter turns, the battery is struggling regardless of what the resting figure claims.
Charging voltage belongs in the same test. Rev the engine and watch the reading — a healthy regulator holds roughly 13.5–14.5V. Over 15V cooks the electrolyte; under 13V leaves the battery chronically undercharged. Both failures kill replacement batteries within a season, and neither is fixed by buying a better brand.
A load test or conductance test confirms what the multimeter suggests. Most battery distributors will run one in a few minutes if you bring the unit in.
Activation and Installation
Dry-charged units Fill with the supplied electrolyte, let the plates absorb for the period the manufacturer specifies, then charge before use. Skipping the initial charge is the single most common way a new dry battery is judged “faulty”.
Charging Use a charger matched to the battery’s capacity, generally around one-tenth of the Ah rating for a slow charge. Fast-charging raises electrolyte temperature and shortens life.
Installation Clean terminals, apply corrosion inhibitor, and torque bolts to spec. A loose terminal arcs and heats; an over-tightened one cracks the case seal. Avoid cable pull and vibration.
Storage A battery left at 12.0V sulfates; one kept on a maintainer at full charge does not. Seasonal riders should plan for a maintainer, not a shelf.
AGM, Gel or Lithium in Group 9
The stock chemistry is AGM, and staying with it keeps installation simple: no charging-profile changes, no regulator questions, no mounting modifications.
Gel versions exist for deep-discharge duty, but they want a different charge profile. Dropping a gel battery into a system tuned for AGM shortens its life.
Lithium packs offer large weight savings and low self-discharge. However, real capacity is often lower than the “lead-acid equivalent,” and cold-weather charging has limits. On a competition machine where weight changes handling, it pays back; on a work ATV, it rarely does.
For Distributors and Wholesalers
Group 9 is one of the highest-volume powersport sizes. What matters when you are stocking it:
- ✓ Consistent case dimensions across production batches.
- ✓ Stated rating basis on capacity for catalog accuracy.
- ✓ Terminal layout verification per batch.
- ✓ Dry versus activated options for turnover/climate.
- ✓ Written warranty terms and technical support.
TCS has manufactured lead-acid motorcycle and powersport batteries since 1995, with a Group 9 unit in both dry-charged and maintenance-free form, OEM/ODM support, and export experience across Southeast Asia, Africa, the Middle East, Europe and Latin America.
Frequently Asked Questions
What are the YTX9-BS dimensions?
The OEM case measures about 152 × 87 × 107 mm. TCS molds at 150 × 86 × 105 mm. Always confirm against the bracket.
How many CCA does a YTX9-BS have?
The OEM rating is 135 CCA at 0°F (−18°C). Beware of “pulse current” numbers from other brands.
Is YTX9-BS the same as 9-B or 9-BS?
No. Group 9, 9B and 9-B are different case families. Dimensions and terminal positions differ.
Why does my new YTX9-BS die within a season?
Usually the charging system. A regulator running above 15V or below 13V will ruin any replacement.
The Short Version
Group 9, 12V, AGM, 135 CCA, positive terminal on the left. Fit by measurement, not by part number alone — and confirm the charging system before blaming the battery.
TCS Battery manufactures a Group 9 replacement in dry-charged and maintenance-free form, with OEM/ODM programs, private labeling and export documentation.