Planet Minis - View Single Post - Import Motor FAQ

Kurlon · 09-17-2006, 10:45 AM

This FAQ is for all Import motors running a stock stroke of 52mm or longer. As you track down relevant info, post to the thread and I'll add it to the FAQ. For shorter stroke motors, there will be a separate FAQ.

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

Transmissions: There are a few variations on a common theme floating around in the gear boxes of various motors. Most all import big displacement mills run a 4 speed box with either an international shift (1d3u) or all up shift pattern.

Jialing
Gear Ratios
1st: 3.181
2nd: 1.705
3rd: 1.238
4th: 0.958
Shaft Sizes
Lifan 120/125
Gear Ratios

Shaft Sizes
Main Shaft: 17mm clutch side, 12mm sprocket side
Counter Shaft: 14mm or 15mm clutch side, 17mm sprocket side

Cams: Remember to verify valve to piston clearance, and valve to valve clearance whenever swapping cams around.

There are many cam specs HERE for comparison amongst the various offerings. You can thank Cyclerider for gathering most of that data.

Jialing 'small valve' head - Uses 'short' E22 style cams with a 3 bolt sprocket. Note that it's been reported later heads have altered geometry, causing valve to valve contact with long duration cams. G1 and G2 Crower grinds are reported to work with both older and newer batches of the Jialing small valve head. As yet no external method of telling old vs new heads apart has been reported. VERIFY valve to valve clearance before running an aftermarket cam!

Crower
Import G1 Grind

Import G2 Grind

Dr ATV
'Takegawa Z40' Grind

Lifan 'Monster' big valve head - Uses Honda CRF style cams. Note, it normally uses a 3 bolt 32 tooth cam sprocket, Honda cams use a 2 bolt pattern. If you use this head on a motor with a 16 tooth crank sprocket, you will need to source a 32 tooth 2 bolt cam sprocket to use Honda cams. Periodically check your cam sprocket for signs of excess wear where the cam cover thrust button contacts, or the inside thrust tab rubs.

Crower
CRF50 G1 Grind

CRF70 G1 Grind

CRF70 G2 Grind

Dr ATV
'Z40' Grind

'Z28' Grind

TBQ Race Grind

Honda TB
'Race Head' Cam

'Stock Head' Cam

Piston Kits: Yeah, right, you're going to leave YOUR's stock...

Countershaft Sprockets: It used to be simple, you just ordered front sprockets for an old Z50 and they'd fit... but some motors started shipping with larger countershafts, with require different sprockets that don't seem to match any existing motors. See which shaft type your motor takes in the specs section, then check out some of the available options.

Coarse 17mm - Aka old Z50
Dr ATV
12 to 17 tooth

12 to 18 tooth

Coarse 20mm - Lifan and Zongshen 54 x 54 motors
Dr ATV
16 and 17 tooth

14 and 15 tooth, may require modification

Common Issues: What to look forward to with your new motor, along with preventative steps or post gotcha fixes.

Clutches
Primary Shaft Mounted Manuals - There are two varieties you'll see, 4 disk and 5 disk, with Jialing being the only one shipping a 5 disk setup at this time.
Slipping Clutch - Put heavier springs in. The most common suggestion is to get a set of clutch springs for a Honda 1999 or later TRX90 and swap them in for better clutch feel and more grabbing power.

5 disk upgrade - Some have sucessfully transplanted a 5 disk clutch stack from a Jialing to other motors that initially had 4 disk setups. This requires modifying the clutch basket, removing material from the bottom of the tab cutouts so the new stack will fit in.

09-17-2006, 10:45 AM	#1 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,851	Import Motor FAQ - Long Stroke Mills This FAQ is for all Import motors running a stock stroke of 52mm or longer. As you track down relevant info, post to the thread and I'll add it to the FAQ. For shorter stroke motors, there will be a separate FAQ. 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 Transmissions: There are a few variations on a common theme floating around in the gear boxes of various motors. Most all import big displacement mills run a 4 speed box with either an international shift (1d3u) or all up shift pattern. Jialing Gear Ratios 1st: 3.181 2nd: 1.705 3rd: 1.238 4th: 0.958 Shaft Sizes Lifan 120/125 Gear Ratios Shaft Sizes Main Shaft: 17mm clutch side, 12mm sprocket side Counter Shaft: 14mm or 15mm clutch side, 17mm sprocket side Cams: Remember to verify valve to piston clearance, and valve to valve clearance whenever swapping cams around. There are many cam specs HERE for comparison amongst the various offerings. You can thank Cyclerider for gathering most of that data. Jialing 'small valve' head - Uses 'short' E22 style cams with a 3 bolt sprocket. Note that it's been reported later heads have altered geometry, causing valve to valve contact with long duration cams. G1 and G2 Crower grinds are reported to work with both older and newer batches of the Jialing small valve head. As yet no external method of telling old vs new heads apart has been reported. VERIFY valve to valve clearance before running an aftermarket cam! Crower Import G1 Grind Import G2 Grind Dr ATV 'Takegawa Z40' Grind Lifan 'Monster' big valve head - Uses Honda CRF style cams. Note, it normally uses a 3 bolt 32 tooth cam sprocket, Honda cams use a 2 bolt pattern. If you use this head on a motor with a 16 tooth crank sprocket, you will need to source a 32 tooth 2 bolt cam sprocket to use Honda cams. Periodically check your cam sprocket for signs of excess wear where the cam cover thrust button contacts, or the inside thrust tab rubs. Crower CRF50 G1 Grind CRF70 G1 Grind CRF70 G2 Grind Dr ATV 'Z40' Grind 'Z28' Grind TBQ Race Grind Honda TB 'Race Head' Cam 'Stock Head' Cam Piston Kits: Yeah, right, you're going to leave YOUR's stock... Countershaft Sprockets: It used to be simple, you just ordered front sprockets for an old Z50 and they'd fit... but some motors started shipping with larger countershafts, with require different sprockets that don't seem to match any existing motors. See which shaft type your motor takes in the specs section, then check out some of the available options. Coarse 17mm - Aka old Z50 Dr ATV 12 to 17 tooth 12 to 18 tooth Coarse 20mm - Lifan and Zongshen 54 x 54 motors Dr ATV 16 and 17 tooth 14 and 15 tooth, may require modification Common Issues: What to look forward to with your new motor, along with preventative steps or post gotcha fixes. Clutches Primary Shaft Mounted Manuals - There are two varieties you'll see, 4 disk and 5 disk, with Jialing being the only one shipping a 5 disk setup at this time. Slipping Clutch - Put heavier springs in. The most common suggestion is to get a set of clutch springs for a Honda 1999 or later TRX90 and swap them in for better clutch feel and more grabbing power. 5 disk upgrade - Some have sucessfully transplanted a 5 disk clutch stack from a Jialing to other motors that initially had 4 disk setups. This requires modifying the clutch basket, removing material from the bottom of the tab cutouts so the new stack will fit in. __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771 Last edited by Kurlon; 11-22-2006 at 12:16 PM.