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YD-MJN

YD-MJN

Yoshimura has dedicated years of research, development, and extensive testing to bring you new carburetors.
It is called YD-MJN (Yoshimura Downdraft - Multiple Jet Nozzle) carburetor, and it is created with a full of our know-how.

There are two different bore size models, YD-MJN24 and YD-MJN28.
Following is the product features and further information.

(All products on this page are prototype)

YD-MJN Structure

YD-MJN Structure

YD-MJN Carburetor is a downdraft carburetor designed for single cylinder engine.
Since the main body leans to engine side, the distance to cylinder is shorter and that makes the Air/Fuel mixture delivery quicker.

YD-MJN Structure

Downdraft structure improves air intake efficiency by the shorter intake.

  • Improvement of performance at high rpm
  • Improvement of throttle response

YD-MJN Structure

MJN (Multiple Jet Nozzle) produces more ideal atomized fuel than ordinary jet needles with the unique structure.
(MJN mechanism)

  • Improvement of combustion efficiency
  • Improvement of throttle response
  • Easier throttle operation by instant throttle response

It is the feature of a downdraft structure that the throttle response is improved by the shorter distance between carburetor center and cylinder, however such short intake often causes insufficient carburetion.
MJN solves the problem and it sprays and deliver an ideal Air/Fuel mixture to cylinder.

YD-MJN Structure

Red top cap is a symbol of MJN carburetor.

Manifolds were specially designed for YD-MJN to realize ideal intake length and position. Two types will be commercialized to enhance the versatility.

  • For Monkey Z50 engine type

YD-MJN Structure

  • Multi-use

YD-MJN Structure

YD-MJN Structure

Short insulator improves air intake efficiency.

Optional parts for YD-MJN Carburetor

Optional parts for YD-MJN Carburetor

Throttle holder set (Exclusive use for YD Carburetor)

  • Gunmetal gray/ L=550mm/ Part No. 671-040-5500
  • Gunmetal gray/ L=650mm/ Part No. 671-040-6500
  • Red/ L=550mm/ Part No. 671-040R5500
  • Red/ L=650mm/ Part No. 671-040R6500

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Optional parts for YD-MJN Carburetor

Aluminium Drain bolt (Red)

  • Part No. 771-C00-6100

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Optional parts for YD-MJN Carburetor

Aluminium air funnel set

  • D=24mm/L=55mm
  • D=28mm/L=45mm

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Optional parts for YD-MJN Carburetor

Jet set (Exclusive use for YD Carburetor)

  • MJ SET/ #72-#95/ Part No. 731-04007295
  • MJ SET/ #98-#120/ Part No. 731-040098120
  • PJ SET/ #35-#58/ Part No. 732-04003558

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Manifold set

  • For Monkey Z50 engine type

YD-MJN Structure

  • Multi-use

YD-MJN Structure

YD-MJN Structure

Manifold Spacer Set T18

YD-MJN Structure

L-form wire adapter

YD-MJN24/28 carburetors were developed and set up with non-Yoshimura 125cc head kit,
Yoshimura exhaust system & Yoshimura C.D.I.