Kawasaki JS400 Battery
1976–1977. The OEM battery case the JS400 takes, the lithium that drops into it, and every model year we have on file. One case across the whole run.
1977 Kawasaki JS400
- OEM battery
- YTX20L-BSYuasa 2026 OEM guide
- Case family
- YTX20L12V starter case
- Fits all years
- 1976–1977same case every year on file
The Kawasaki JS400 takes the YTX20L-BS case. The Antigravity ATX20 RE-START is a drop-in for that case: 680 cranking amps, 4 lb, a built-in jump start that saves enough charge to get you home.
See the Antigravity ATX20
JS400 battery by model year
| Model years | OEM battery | Where it comes from | Lithium that fits |
|---|---|---|---|
| 1976–1977Your year · 1977 | OEM batteryYTX20L-BS12V starter case | Where it comes fromYuasa 2026 OEM guide | Lithium that fitsAntigravity ATX20 RE-START →Antigravity ATX20-HD →Ionic S6 → |
Trim covered: JS400.
Shop all Kawasaki Jet Ski batteriesWhat the JS400 needs, in plain English
Every JS400 from the first 1976 model through 1977 starts on the YTX20L-BS case, a 12-volt starter battery. Kawasaki ships it with a lead-acid battery that starts to fade after two or three seasons of short rides and off-season storage, and that is usually the day a rider goes looking for something better.
The lithium drop-in is the Antigravity ATX20 RE-START: 680 cranking amps, 4 pounds, the same case in lithium. Its RE-START function puts the battery to sleep before a parasitic draw can drain it, then wakes it with one press for a jump start. Charge it with a lithium-compatible charger or maintainer for the off-season and it outlasts the lead-acid battery it replaces by years.