EPA engine family

Engine family NAMSC.049MC1

If this code is printed on your emission label, this is your machine's federal record: sold under Amstar Motors LLC, with an engine built by Taizhou Zhongneng (ZNEN), certified as street-legal scooters and motorcycles.

Displacement: 49cc
Model years: 2022
Models certified: 26
Certificates: 1

What this record says

Sold in the US by: Amstar Motors LLC
Engine built by: Taizhou Zhongneng (ZNEN)
Vehicle category: Highway Motorcycle - Ia (<50cc)
Certificate numbers: NAMSC.049MC1-002

What the number itself says

Reading NAMSC.049MC1 left to right: N is the model-year letter for 2022, AMS is the three-character code the EPA assigned to Amstar Motors as certificate holder, C marks a highway (street-legal) certification, .049 is the displacement in litres, so 49cc and MC1 is Amstar Motors' 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 test vehicle Amstar Motors submitted for this family (model ZNEN-Bomb 50) carried engine code BN139QMB. In the Chinese engine-model convention that reads as one cylinder with a nominal 39 mm bore, QMB series. Against the certified 49cc that implies a stroke of roughly 41 mm — a sanity check for a piston or cylinder listing, not a published figure.

The certificate describes a four-stroke, single-cylinder engine with 2 valves per cylinder fed by carburettor, run by an ignition control module (CDI-type ignition). 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 2.2 kW (about 3 hp) at 7,500 rpm, driving through a CVT (belt and variator).

Engine code on test vehicle: BN139QMB
Nominal bore (from the code): 39 mm · implied stroke ≈ 41 mm
Cylinders / valves: 1 · 2 per cylinder
Cycle: four-stroke
Fuel delivery: carburettor
Oxygen sensor: no
Engine control: ICM
Catalytic converter: TWC, single bed, open loop
Air injection: PAIR
Rated power: 2.2 kW (≈3 hp)
Rated speed: 7,500 rpm
Transmission: CVT (belt and variator)
Sales area: 50S
Vehicle built by: Taizhou Zhongneng Motorcycle Co.,Ltd.
Test vehicle model: ZNEN-Bomb 50

Filing history and where it was sold

Amstar Motors filed one certificate under this family, for model year 2022, sold as 50-state, California included.

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

Certified emission levels: CO 2.5, HC 0.3 g/km.

What this configuration means when you shop for parts

Amstar Motors certified the BN139QMB 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 39 mm bore in the code gives the engine size, not the carburettor size — measure the intake bore and the mounting on the BN139QMB before ordering.

The CVT behind the BN139QMB 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 ZNEN-Bomb 50 rather than ordering by displacement.

The PAIR valve Amstar Motors lists on the BN139QMB is an emissions part; its hoses perish and are the usual cause of popping on the overrun.

The exhaust on Amstar Motors' NAMSC.049MC1 carries a catalyst, so a replacement silencer without one changes what the BN139QMB was certified with.

Other records carrying the same engine code

Amstar Motors certified an engine with this code under 16 other family numbers — the same engine filed again in another year, or in an off-road and a street version:

Other certificate holders whose test vehicle carried the same engine code (10 of 34 shown):

Bintelli LLCGGTRC.049MC12016 · same engine factory
Bintelli LLCFGTRC.049ZNE2015 · same engine factory
Bintelli LLCEGTRC.049ZNE2014 · same engine factory
Bintelli LLCDGTRC.049ZNE2013 · same engine factory
BMS Motorsports, Inc.HBMSC.049MC12017 · same engine factory
BMS Motorsports, Inc.GBMSC.049MC12016 · same engine factory
BMS Motorsports, Inc.FBMSC.049MC12015 · same engine factory
BMS Motorsports, Inc.EBMSC.049ZNE2014 · same engine factory
BMS Motorsports, Inc.DBMSC.049ZNE2013 · same engine factory
BMS Motorsports, Inc.CBMSC.049ZNE2012 · same engine factory

A shared code from the same factory is a strong search lead. From a different factory it is as often a naming coincidence. Either way it narrows the search; it does not settle it — measure before you buy.

Models certified under NAMSC.049MC1

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.

Aurora 50 · Aurora-S 50 · Bull II 50 · Canoe 50 · Canoe III 50 · Cross 50 · F10 · Falcon7 50 · Frigate 50 · Grace 50 · JOC 50 · Jazz 50 · R8 50 · Revival 50 · Revival2 50 · Shuttle 50 · Snail 50 · Sun 50 · Sun3 50 · Trophy 50 · VPA 50 IV · Vector 50 · Veracruz 50 · ZN50QT-50 · ZN50QT-G · ZNEN-Bomb 50

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.