Fine-tune your air-fuel ratio with these high-precision Keihin Small Round 4mm Main Jets. Designed for Keihin PB, PAB, and CVK series carburetors, these are the standard jet for optimizing performance after installing a big-bore kit, exhaust, or high-flow air filter. The M4x0.70 thread and 5mm round head match the Keihin 99101-116 style used across a wide range of 50cc�150cc scooters. Available in 15 sizes from #75 to #130 � select your size from the variant dropdown.
Compatibility note: These are Keihin "Small Round" (99101-116) style jets. Not compatible with Keihin "Large Round" (99101-393) or "Hex" (99101-357) styles. Verify your jet dimensions before ordering.
Jetting tip: Always start with a larger jet than you think you need and work down. Running too lean can cause engine overheating and permanent damage. See our Jetting Instructions for a full guide.
California Prop 65 Warning: www.p65warnings.ca.gov
