Before you buy
1 known problem- Learner legal
- LAMSYes, every version sold here is LAMS approved.
- On the registers as
EX400G- Watch for
-
mediumClutch slip and premature wear
- Running cost
- Valve check every 24,000km (US manual; AU/NZ owners report 42,000km, unverified)unverified · $5.5k–$8.5k used est. Aug 2026
Recalls
1 on recordAsk the seller for proof the recall work was done; a dealer can check by VIN. Search any bike at vehiclerecalls.gov.au.
Overview
The Ninja 400 dominated the LAMS sports bike category throughout its production. Replacing the heavier Ninja 300, it brought a larger 399cc engine, a significantly lighter trellis frame, and sharper handling. It is widely considered one of the best learner bikes ever made, offering enough performance to keep experienced riders entertained on a track day. Servicing note: we list the valve-clearance interval as 24,000km, the figure printed in the North American owner's manual (2018 edition, Kawasaki part 99987-1994), which we have read. Australian and New Zealand owners report that their manuals (code 99986-0102, EX400GK/JK) list 42,000km instead, and the platform has the same split elsewhere: the Z400 service manual specifies 24,000km for Canadian bikes and 42,000km everywhere else, which points at North American emissions certification rather than anything mechanical. That 42,000km figure is unverified: it comes from owners quoting their manuals, and nobody here has checked an Australian-delivered manual, so the field stays flagged until someone does. Budget for 24,000km, and check the chart in your own bike's manual.
Engines & variants
399cc Parallel Twin (LAMS)LAMS approved
Under the limits as standard. No ECU or mechanical restrictions.
Compliance-plate model code:
EX400G
- NSW and Victoria both file it under the model code EX400G rather than the marketing name, and both scope the entry to 2018-on — the year this bike replaced the Ninja 300.
- All three state registers list it, so this is a lookup problem, not an approval one.
Pros
- Class-leading power-to-weight ratio for a learner bike
- Assist and slipper clutch provides an incredibly light lever pull
- Fantastic handling out of the box
Cons
- Standard seat is thin and uncomfortable on long rides
- Factory clutch springs are too soft
Known problems
unverified marks a figure we could not confirm against a manufacturer source. It is our best reading of what is published, not a checked fact — confirm it yourself before you spend money on the strength of it.
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