EPA engine family

Engine family CJAJC.049S4A

If this code is printed on your emission label, this is your machine's federal record: sold under Jiajue U.S.A. LLC, with an engine built by Zhejiang Jiajue, certified as street-legal scooters and motorcycles.

Displacement: 49cc
Model years: 2012
Models certified: 18
Certificates: 1

What this record says

Sold in the US by: Jiajue U.S.A. LLC
Engine built by: Zhejiang Jiajue
Vehicle category: Highway Motorcycle - Ia (<50cc)
Certificate numbers: CJAJC.049S4A-001

What the number itself says

Reading CJAJC.049S4A left to right: C is the model-year letter for 2012, JAJ is the three-character code the EPA assigned to Jiajue U.S.A. as certificate holder, C marks a highway (street-legal) certification, .049 is the displacement in litres, so 49cc and S4A is Jiajue U.S.A.'s own sequence for that year. Nothing in the number names the factory — that comes from the certificate itself.

The engine, as described on the certificate

The certificate describes a four-stroke, single-cylinder engine with 2 valves per cylinder fed by carburettor. There is a catalytic converter in the exhaust, recorded as "TWC, single bed, open loop". The head carries a pulse secondary-air (PAIR) valve.

Rated power on the record is 2 kW (about 3 hp) at 7,500 rpm, driving through a CVT (belt and variator).

Cylinders / valves: 1 · 2 per cylinder
Cycle: four-stroke
Fuel delivery: carburettor
Oxygen sensor: no
Catalytic converter: TWC, single bed, open loop
Air injection: PAIR
Rated power: 2 kW (≈3 hp)
Rated speed: 7,500 rpm
Transmission: CVT (belt and variator)
Sales area: 49S
Vehicle built by: Zhejiang Jiajue Motorcycle Manufacturing Co.,Ltd
Test vehicle model: JJ50QT-13

Filing history and where it was sold

Jiajue U.S.A. filed one certificate under this family, for model year 2012, sold as 49-state (not certified for sale in California).

The vehicle itself is recorded as built by the same company, Zhejiang Jiajue Motorcycle Manufacturing Co.,Ltd in China — engine and chassis from one source.

Certified emission levels: CO 1.6, HC 0.2 g/km.

What this configuration means when you shop for parts

Jiajue U.S.A. certified this 49cc engine with a carburettor at 49cc, so the fuel-side wear items are the carburettor, its jets and float needle, the intake boot and the choke. The record gives no carburettor part number — measure the intake bore and the mounting on this 49cc engine before ordering.

The CVT behind this 49cc engine makes its drive belt, variator rollers and clutch shoes the consumables; belt length and width vary between 49cc machines, so measure the old belt on the JJ50QT-13 rather than ordering by displacement.

The PAIR valve Jiajue U.S.A. lists on this 49cc engine is an emissions part; its hoses perish and are the usual cause of popping on the overrun.

The exhaust on Jiajue U.S.A.'s CJAJC.049S4A carries a catalyst, so a replacement silencer without one changes what this 49cc engine was certified with.

Models certified under CJAJC.049S4A

Every model designation the importer listed on this certificate. If your machine's model name appears here, this is the right record — even if the name on the bodywork is slightly different.

JJ50QT-11 · JJ50QT-11A · JJ50QT-11B · JJ50QT-11C · JJ50QT-13 · JJ50QT-15 · JJ50QT-17 · JJ50QT-22 · JJ50QT-22A · JJ50QT-22B · JJ50QT-22C · JJ50QT-22D · JJ50QT-23A · JJ50QT-23B · JJ50QT-3 · JJ50QT-3A · JJ50QT-4 · JJ50QT-8

Other American badges on engines from the same factory

Related in the registry

Source. US EPA annual certification data — EPA Certified Highway Motorcycle Test Results, MY2006-present; EPA Certified Off-Road Motorcycle / ATV / UTV / Rec Vehicle, MY2006-present. Retrieved 2026-09-07. Full provenance and method.