Engine Sprocket
We’ve several rear sprocket options available for our customers to “fine tune” their gas operated bike to accomplish their desired optimal speed/power gear ratio.
A note to keep in mind: The larger the trunk sprocket, the slower the bike will go, but will have capacity to climb hills. The smaller the trunk sprocket, the quicker the bike will move, but will climb hills less effectively. You are trading power for acceleration or vice versa.
We offer sizes of 36 tooth, 44 tooth, 48 tooth, and 56 tooth sprockets in the Large 9-hole gear. The internal diameter is 1.4″, hole spacing can be 1″. Find table below for specifications. Commonly, the large 9-hole sprocket with 48 tooth configuration will come with the 4G T-Belt Drive 4-stroke engine kit.

Rear Sprocket (Large 9 Hole) Hole Spacing Inner Diameter Outer Diameter Best Speed Acceleration/Power Included With
36 Tooth 1″ 1 13/32″ 5 7/8″ Fast Low Sold Separately
44 Tooth 1″ 1 13/32″ 7″ Moderate+ Moderate- Sold Separately
48 Tooth 1″ 1 13/32″ 8 1/8″ Moderate- Moderate+ 4G T-Belt
56 Tooth 1″ 1 13/32″ 9″ Slower High Sold Separately

The tiny 9-hole sprockets can be found in two sizes, 44 tooth and 50 tooth. The internal diameter is definitely 1.39″ and hole spacing is 1″. See table below for specs. The small 9-hole 44 tooth sprocket should come with the SkyHawk Angle Fire 2-stroke engine kit.

Rear Sprocket (Small 9 Hole) Hole Spacing Internal Diameter Outer Diameter Best Speed Acceleration/Power Included With
44 Tooth 1″ 1.39″ 7 1/8″ Moderate+ Moderate- SkyHawk Angle Fire
50 Tooth 1″ 1.39″ 8 1/8″ Gradual High Sold Separately

We also carry 5-hole sprockets in 44 tooth, and 48 tooth sizes. The internal diameter is 2.5″ and the hole spacing can be 2″. Outer diameters are 7″ for the 44 tooth and 8″ for the 48 tooth

Rear Sprocket (5 Hole) Hole Spacing Inner Diameter External Diameter Best Speed Acceleration/Power Included With
44 Tooth 2″ 2.5″ 7″ Moderate+ Moderate- SkyHawk Angle Fire
48 Tooth 2″ 2.5″ 8″ Moderate- Moderate+ Sold Separately

We provide a 6-hole sprocket in 36 tooth, 44 tooth, and 50 tooth sprocket sizes. Inner diameter 1.8″ and hole spacing of just one 1.5″. Outer diameters are 5 7/8″ for the 36 tooth, 7.25″ for the 44 tooth, and 8 1/8″ for the 50 tooth

Back Sprocket (6 Hole) Hole Spacing Inner Diameter External Diameter Top Speed Acceleration/Power Included With
36 Tooth 1.5″ 1.8″ 5 7/8″ Fast Slow Sold Separately
44 Tooth 1.5″ 1.8″ 7 1/4″ Moderate+ Moderate- Sold Separately
50 Tooth 1.5″ 1.8″ 8 1/8″ Gradual High Sold Separately

We provide a disc brake sprocket that bolts to the brake rotor hub in a 44 tooth sprocket. Internal diameter is usually 1.29″ and hole spacing is 1″ with an external diameter of 7″

Disc Brake Sprocket (9 Hole) Hole Spacing Inner Diameter Outer Diameter Top Speed Acceleration/Power Included With
44 Tooth 1″ 1.29″ 7″ Moderate+ Moderate- Sold Separately
Ever-power Engine Sprocket Shaft
Description
Description for Ever-power Engine Sprocket Shaft
• Pins and shafts are machined from super-difficult, aircraft-rated Durabar 60 metal and bearing surfaces are surface to a 16 micron finish
• Deep heat-treating provides 60-63 Rockwell hardness and CNC machined tapers assure concentricity within .0003″
• 3-hole crank pin design distributes oil similarly to both rod races
• Annealed threads on shafts allow torquing up to 100 ft. lbs. over the OEM specifications
ENGINE SPROCKET, 13T
This sprocket was originally designed for the Yerf Dog Spiderbox GX150. It’ll fit the majority of GY6 engines without invert.
In case you are choosing to remove a reverse box rather than replacing it, you can use this sprocket to do away with the whole setup cleanly.