EPA engine family

Engine family ATTNC.049MD1

If this code is printed on your emission label, this is your machine's federal record: sold under Titan Imports Inc., with an engine built by Zhejiang Kaikai Meiduo Locomotive Co.Ltd, certified as street-legal scooters and motorcycles.

Displacement: 49cc
Model years: 2010
Models certified: 24
Certificates: 1

What this record says

Sold in the US by: Titan Imports Inc.
Engine built by: Zhejiang Kaikai Meiduo Locomotive Co.Ltd.
Vehicle category: Highway Motorcycle - Ia (<50cc)
Certificate numbers: ATTNC.049MD1-001

What the number itself says

Reading ATTNC.049MD1 left to right: A is the model-year letter for 2010, TTN is the three-character code the EPA assigned to Titan Imports as certificate holder, C marks a highway (street-legal) certification, .049 is the displacement in litres, so 49cc and MD1 is Titan Imports' 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 Titan Imports submitted for this family (model MD50QT-15) carried engine code 139QMB. 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 2.1 kW (about 3 hp) at 7,000 rpm, driving through a CVT (belt and variator).

Engine code on test vehicle: 139QMB
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: 2.1 kW (≈3 hp)
Rated speed: 7,000 rpm
Transmission: CVT (belt and variator)
Sales area: 49S
Vehicle built by: Zhejiang Kaikai Meiduo Locomotive Co.Ltd.
Test vehicle model: MD50QT-15

Filing history and where it was sold

Titan Imports filed one certificate under this family, for model year 2010, sold as 49-state (not certified for sale in California).

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

Certified emission levels: CO 2.5, HC 0.9 g/km.

What this configuration means when you shop for parts

Titan Imports certified the 139QMB 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 139QMB before ordering.

The CVT behind the 139QMB 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 MD50QT-15 rather than ordering by displacement.

The PAIR valve Titan Imports lists on the 139QMB is an emissions part; its hoses perish and are the usual cause of popping on the overrun.

The exhaust on Titan Imports' ATTNC.049MD1 carries a catalyst, so a replacement silencer without one changes what the 139QMB was certified with.

Other records carrying the same engine code

Titan Imports certified an engine with this code under 5 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 32 shown):

Earthstone Studio LLC Dba Owl Scooter9OWLC.049MD12009 · same engine factory
Benyate Motorsport LLCTBYMC.049MC12026 · different engine factory
Benyate Motorsport LLCSBYMC.049MC12025 · different engine factory
Benyate Motorsport LLCRBYMC.049MC12024 · different engine factory
Benyate Motorsport LLCPBYMC.049MC12023 · different engine factory
Benyate Motorsport LLCNBYMC.049MC12022 · different engine factory
Benzhou (Usa) Vehicle Industry Group Co., Ltd.8BNZC.050SA12008 · different engine factory
Dafier, Inc.FDFRC.049QQA2015 · different engine factory
Dafier, Inc.EDFRC.049QQA2014 · different engine factory
Dafier, Inc.DDFRC.049QQA2013 · different 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 ATTNC.049MD1

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.

Meiduo MD50QT · Meiduo MD50QT-10 · Meiduo MD50QT-11 · Meiduo MD50QT-15 · Meiduo MD50QT-2 · Meiduo MD50QT-3 · Meiduo MD50QT-4 · Meiduo MD50QT-5 · Meiduo MD50QT-6 · Meiduo MD50QT-7 · Meiduo MD50QT-8 · Meiduo MD50QT-9 · Velocity MP50QT · Velocity MP50QT-10 · Velocity MP50QT-11 · Velocity MP50QT-12 · Velocity MP50QT-2 · Velocity MP50QT-3 · Velocity MP50QT-4 · Velocity MP50QT-5 · Velocity MP50QT-6 · Velocity MP50QT-7 · Velocity MP50QT-8 · Velocity MP50QT-9

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.