Engine Fluids, Gear Oil & Filter Specifications
| Engine Oil Viscosity & JASO/API Standard | SAE 10W-40 | API SG/SL | JASO MB |
|---|---|
| Engine Oil Drain & Refill Capacity | 1.5 L (Without Filter Change) / 1.7 L (With Filter Replacement) |
| Final Drive / Gearbox Oil Viscosity & Capacity | SAE 10W-40 or SAE 80W-90 | 250 ml (Drain) / 270 ml (Total) |
| OEM Oil Filter Part Number | Cartridge Filter OEM # 5RU-13440-00 |
| OEM Air Filter Element Part Number | OEM Dual Filters # 5RU-14451-00 & 5RU-14461-00 |
| Spark Plug Model & Electrode Gap | NGK CR8E (0.7 – 0.8 mm gap) |
Field note: The Majesty 400 utilizes dual air filter elements (# 5RU-14451-00 and # 5RU-14461-00) that must both be replaced at regular maintenance intervals. Ensure 1.7 L oil capacity with filter replacement. Compare specifications with the Yamaha TMAX 530 guide and Yamaha XMAX 300 guide. For heavy clutch and belt maintenance diagnostic procedures, refer to our maxi-scooter clutch chatter & belt wear guide.
Engine Lubrication System
| Component | Engine Oil Filter |
|---|---|
| OEM Part Number | 5RU-13440-00 |
| Dimensions | Paper cartridge |
| Torque Spec | Filter cover: 10 Nm (7.2 lbf·ft) |
| Fluid Spec | 10W-40 API SG |
| Cross-Compatibility | Yamaha Morphous 250 |
Field note: Exceeding 10 Nm on the filter cover warps the thin cast aluminum housing and causes a slow oil seep that is easy to overlook during a quick post-service inspection since it often appears only after the engine reaches full operating temperature. Always double-check for leaks on a fully warmed-up engine, not just at idle.
CVT Transmission System
| Component | Drive V-Belt |
|---|---|
| OEM Part Number | 5RU-17641-00 |
| Dimensions | Double-cog, Kevlar reinforced |
| Torque Spec | Primary sheave nut: 83 Nm (61 lbf·ft) |
| Cross-Compatibility | Unique to YP400 (2004-2014) |
Field note: Because this belt has no cross-compatible substitute and the platform is discontinued, a botched install often means a long parts search rather than a same-day fix. Under-torquing the 83 Nm primary sheave nut is the leading cause of nut back-off and crankshaft taper wear reported on this model — always use a calibrated torque wrench rated for this range, and never substitute an impact gun "to save time."
Engine Internals: Cylinder Head & Crankshaft
| Part No. | Qty | Part Name | Notes |
|---|---|---|---|
| 5RU-11181-00 | 1 | Head Comp., Cylinder | Resurface flatness tolerance 0.05mm max |
| 5RU-12101-00 | 1 | Valve, Inlet | Do not swap positions with exhaust valve |
| 5RU-11351-00 | 1 | Gasket, Cylinder Head | Single-use metal composite; never reuse |
| 5RU-11421-00 | 1 | Camshaft Comp. | Chain-driven; inspect lobe wear before reinstall |
| Part No. | Qty | Part Name | Notes |
|---|---|---|---|
| 5RU-11400-00 | 1 | Crankshaft Comp. | Heavier 400cc-class crank; check runout < 0.03mm |
| 5RU-11650-00 | 1 | Connecting Rod | Big-end side clearance spec: 0.1-0.4mm |
| 5RU-11631-00 | 1 | Piston (Std.) | Domed piston, 3-ring set |
| 5RU-11633-00 | 1 | Piston Pin | Lightly oil before install; hand-pressure fit only |
| 5RU-11635-00 | 2 | Piston Pin Clip (Circlip) | Directional installation — see expert note below |
Field note: On this discontinued 400cc platform, sourcing a replacement piston or pin after an ejected
circlip incident can mean a long parts search. The clip's opening gap must face 90° to piston travel,
never fore-or-aft — a backward clip compresses under load until it ejects into the crankcase, and
the freed pin gouges the cylinder wall on the next stroke, destroying the bore. Use only new clips and
confirm full seating by feel.
OEM Body Panels & Color Matching
| Part Name | Team Yamaha Blue | Absolute Black | Pearl White |
|---|---|---|---|
| Front Cowl | Consult Service Manual | Consult Service Manual | Consult Service Manual |
| LH Side Panel | Consult Service Manual | Consult Service Manual | Consult Service Manual |
| RH Side Panel | Consult Service Manual | Consult Service Manual | Consult Service Manual |
| Windscreen | Consult Service Manual | Consult Service Manual | Consult Service Manual |
| Rear Trunk Cover | Consult Service Manual | Consult Service Manual | Consult Service Manual |
Field note: Given this platform's discontinued status, assume the plastic mounting tabs behind the
painted surface are already past the typical three-year UV brittleness threshold on most surviving units.
Never use an impact driver on body screws, and apply silicone grease to rubber grommets before removal
— color-matched replacement panels are frequently unavailable for this model.
Official Technical Reference
The specifications above are cross-checked wherever possible, but this guide does not replace the factory service manual. Before ordering parts or performing a repair, confirm current fitment and revision bulletins directly with Yamaha Motor USA.
Visit Yamaha Motor USA Official Site & Parts Resources