Engine Sprocket
We've several rear sprocket options available for our clients to “fine tune” their gas operated bicycle to achieve their desired optimal velocity/power gear ratio.
A note to keep in mind: The larger the trunk sprocket, the slower the bike will go, but will have power to climb hills. The smaller the trunk sprocket, the quicker the bike will go, but will climb hills less successfully. You are trading power for quickness or vice versa.
We offer sizes of 36 tooth, 44 tooth, 48 tooth, and 56 tooth sprockets in the Large sprockets 9-hole gear. The inner diameter is usually 1.4", hole spacing is certainly 1". Find table below 
for specs. Commonly, the large 9-hole sprocket with 48 tooth configuration should come with the 4G T-Belt Drive 4-stroke engine kit.
Rear Sprocket (Large 9 Hole) Hole Spacing Internal 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 come in two sizes, 44 tooth and 50 tooth. The internal diameter can be 1.39" and hole spacing is 1". See desk below for specs. The tiny 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 Top 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" Sluggish High Sold Separately
We also carry 5-hole sprockets in 44 tooth, and 48 tooth sizes. The internal diameter can be 2.5" and the hole spacing is 2". Outer diameters are 7" for the 44 tooth and 8" for the 48 tooth
Back 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 offer a 6-hole sprocket in 36 tooth, 44 tooth, and 50 tooth sprocket sizes. Internal 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" Sluggish High Sold Separately
We provide a disc brake sprocket that bolts to the brake rotor hub in a 44 tooth sprocket. Inner diameter is definitely 1.29" and hole spacing is 1" with an outer diameter of 7"
Disc Brake Sprocket (9 Hole) Hole Spacing Inner Diameter Outer Diameter Best 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-challenging, aircraft-rated Durabar 60 steel and bearing areas are surface to a 16 micron finish
• Deep heat-treating provides 60-63 Rockwell hardness and CNC machined tapers ensure concentricity within .0003″
• 3-hole crank pin design distributes oil equally 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 made for the Yerf Dog Spiderbox GX150. It will fit the majority of GY6 engines without reverse.
If you are choosing to eliminate a reverse box rather than replacing it, you may use this sprocket to do away with the whole setup cleanly.