I am looking at purchasing an aftermarket 70cc big bore kit for a Kymco People 50 2-stroke scooter. The issue is that I don't know what engine this has. It seems that the 4-stroke "4T" model uses a common QMB139, but I'm not even really sure about that. So if anyone happens to know, that would be really helpful and much appreciated.

Also, if you can suggest a 70cc upgrade kit that you've had success with that would be great too.


1 Answer 1


This web site gives these specifications for the motor:

Bore (in)                1.54
Bore (mm)                39
Compression Ratio        7.21
Cooling                  Air
Cylinders                1
Displacement (cc)        49.5
Displacement (ci)        3
Engine Configuration     Single-Cylinder
Engine Immobilizer       Not Available
Engine Type              2-Stroke
Fuel Injector            No
Fuel Requirements        Regular
Fuel System Type         Carburetor
Number Of Carburetors    1
Speed Governor           No
Starter                  Electric / Kick
Stroke (in)              1.63
Stroke (mm)              41.4
Valve Configuration      Reed Valve

It appears from the specs that the differences are between the People 50/150/250 models, not amongst the models themselves. The 150 and 250 use the four stroke motor, while the 50 is a 2-stroke. I'm pretty sure there is only a single 2-stroke motor which is used in the People 50 and not multiple different engine models.

Malossi makes a big bore cylinder kit for your scooter. This is just a suggestion, not an endorsement.

  • Thank you @Paulster2, this is good info to have. I'm wondering if maybe the engine isn't a "standard" one that is used in various different scooter brands (e.g. that qmb139) but rather a specifically Kymco setup. Either way I guess it's not important as long as a kit can be located and is assured to fit. Thanks for the link to the Malossi kit, they appear to be very good from the reviews. But for a savings of $50 I'm considering a Hoca version. Any thoughts on that?
    – stotrami
    Oct 6, 2014 at 3:15
  • @stotrami - Since I do not have any specific experience with them, I'm deign to recommend one. Besides, this SE site is not about recommendations, as they become obsolete. My suggestion of the Malossi was just to show there are kits out there available. Also, make sure you rejet your carburetor so you don't run into a lean condition after installation. Oct 6, 2014 at 11:03
  • 1
    10-4 good buddy, I'll be sure to perform my own due diligence on the selection of a kit. Thank you for the tip on the carb jets, and your time in helping us out!
    – stotrami
    Oct 6, 2014 at 21:46

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