Pit Bike Club - Motor Identification

Hey Guys,

Im borrowing this Info from PlanetMinis its decent stuff in Identifing you Pit Bike motor..

Identification: There are many many different importers bringing over either crate motors, or entire bikes under a variety of labels. In most cases, the actual 'brand' of the motor can be traced back to a small group of producers in China. Generally speaking motors of a particular model number from a given producer will stick to a single common specification, so once you've identified your motor you can feel confidant ordering parts based on that ID.

Lately though with the larger displacement motors we're seeing variations even within a particular make and model of motor. Motors where inconsistencies have been observed that are more than just normal design updates over the life of a product will be noted. On these machines, you'll need to measure your machine specifically to determine which parts are appropriate.

Lifan - One of the most well known import brands. Like most manufacturers anyone can have a motor produced by Lifan with their name on the side, and some people buy Lifan side covers to slap on lessor motors so don't use those labels as reliable identifiers.
Identifying Marks

Known Lifan Motors
* SDG Pro Mini's '125' motor is basically a Lifan Monster 120 motor. This unit is a bit unique in that Lifan assigns SDG a unique model number rather than using their standard model number schema.

Jialing - Made 'famous' by GPX / Pitster Pro importing them with much fanfare starting in 2005.
Identifying Marks

Known Jialing Motors
* GPX 125

Zongshen - Runner up to Lifan and Jialing for brand recognition.
Identifying Marks

Known Zongshen Motors
* RCM bikes in 2005 and 2006 utilized Zongshen powerplants.

Loncin - Ebay favorite, no known 'big' import brands use this make of motor in their bikes, but many smaller brands do.
Identifying Marks

Known Loncin Motors

Ducar - Less seen than even Loncin, typically found on Ebay.
Identifying Marks

Known Ducar Motors

Faddybike - Produced in Thailand as a clone of the Honda Nice/Wave powerplant.
Identifying Marks

Known Faddybike Motors

Motor Specs: There are a few basic stats that help determine what parts will fit which motor. They also can help determine when you can 'borrow' bits from other motors to use as hop ups by cross referencing other machines with similar base specs.

To stay consistent, a few measurements will be based on the following giudelines when there is a chance for ambiguity:

Piston Pin Height: Measure from the TOP of the pin hole to the top of the outer edge of the piston. Some people measure to the middle of the pin hole, but this method allows or a direct read with a ruler or set of calipers making it simpler for others to check and compare.

Stud Spacing: Until a better way of quantifying stud spacing is developed, one motor will be designated as the 'reference' mill for a given stud pattern. All motors that are compatible will list that motor under stud spacing.

Lifan 'Monster' 120
Brand: Lifan
Bore: 52.4mm
Stroke: 55.5mm
Piston Pin: 14mm
Piston Pin Height: 12.8mm
Cylinder Height: 79mm
Stud Spacing: Lifan Monster Standard
Clutch: 4 disc primary mount
Oil Pump: Direct crank drive
Transmission: 4 speed, 1d3u or 4u depending on shift drum used
Countershaft: Coarse 17mm
Start in gear: Yes
Head: 27mm intake, 23mm exhaust, Honda CRF50 style cam

Zongshen 120
Brand: Zongshen
Bore: 52.4mm
Stroke: 55.5mm
Piston Pin: 14mm
Piston Pin Height:
Cylinder Height:
Stud Spacing:
Clutch:
Oil Pump:
Transmission: 4 speed
Countershaft: Coarse 17mm
Start in gear:
Head: 27mm intake, 23mm exhaust

Zongshen 124
Brand: Zongshen
Bore: 54mm
Stroke: 54mm
Piston Pin: 14mm
Piston Pin Height:
Cylinder Height:
Stud Spacing:
Clutch:
Oil Pump:
Transmission: 4 speed
Countershaft: Coarse 20mm
Start in gear: No
Head: 27mm intake, 23mm exhaust

'GPX' 125
Brand: Jialing
Bore: 52.4mm
Stroke: 57.5mm
Piston Pin: 13mm
Piston Pin Height: 13mm
Cylinder Height: 79mm
Stud Spacing: Lifan Monster Standard
Clutch: 5 disc primary mount
Oil Pump: Direct crank drive
Transmission: 4 speed, 1d3u or 4u depending on shift drum used
Countershaft: Coarse 17mm
Start in gear: Yes
Head: 23mm intake, 20mm exhaust, uses 'E22' style cam, short

Yx 150cc Motor:

Engine Specs:

150cc Air Cooled Four Stroke
53mm stroke
60mm bore
Compression Ratio: 9.2:1
Power and Torque: 11HP/9500°500R/min
Max. Torque: 11N.m/5500°500R/min
KLX110 Style Head

Transmission Specs:

4-Speed All Up Transmission (N-1-2-3-4)
Manual Clutch (start in any gear)
Transmission Ratio:
First Gear: 3.272 (11/36)
Second Gear: 1.937(16/31)
Third Gear: 1.35(20/27)
Fourth Gear: 1.043(23/24)
Starts in gear: Yes

Yx 160cc Motor:

Engine Specs:

160cc Air Cooled Four Stroke
57mm stroke
60mm bore
Compression Ratio: 9.2:1
Power and Torque: 11HP/9500°500R/min
Max. Torque: 11N.m/5500°500R/min
KLX110 Style Head

Transmission Specs:

4-Speed All Up Transmission (N-1-2-3-4)
Manual Clutch (start in any gear)
Transmission Ratio:
First Gear: 3.272 (11/36)
Second Gear: 1.937(16/31)
Third Gear: 1.35(20/27)
Fourth Gear: 1.043(23/24)
Starts in Gear: Yes