Recommended Carburetor Size

With all racing engines, the more air you can flow into the cylinder at a high velocity, the more power that can be obtained. Below are measurements of different reed valve assemblies measured at 10" of pressure drop, with all figures corrected for temperature and humidity. (Note: that CFM is cubic feet of air per minute.)

Engine Carburetors
80cc 26/28mm
125cc 34/35mm
250cc 35/36mm
500cc 36/38mm

Dare to Compare - Airflow

**Mossbarger Power Reed** 79.80 CFM
Honda CR500 (10-Petal 89-90) 68.88 CFM
**Mossbarger Power Groove Reed (BIG)** 73.68 CFM
**Mossbarger Power Groove Reed (SMALL)** 60.36 CFM
Honda CR500 (84-88) 73.68 CFM
Kawasaki KX/KXT 250 63.02 CFM
Suzuki RM/LT 250-500 64.40 CFM
Yamaha YZ250/490 64.80 CFM
**Mossbarger Power Groove Reed** 53.26 CFM
Boysen Rad Valve 250cc 64.68 CFM
Cagiva 125 1988 38.94 CFM
FMF 250cc 53.26 CFM
Honda CR/TRX/ATC25OR 54.60 CFM
Honda CR125R all 53.26 CFM
Kawasaki KX125 49.56 CFM
Suzuki RM250 1987 53.26 CFM
Suzuki RM125 (87-88 95-96) 53.26 CFM
Suzuki RM125 1989 35.28 CFM
Suzuki LT250/500 88-89 56.40 CFM
Yamaha TRI-Z 250 55.44 CFM
Yamaha YZ250 1989 50.40 CFM
Yamaha TZ250 U 1989 60.10 CFM
Yamaha YZ125 80-87 50.60 CFM
Yamaha YZ125 88-89 50.40 CFM
**Mossbarger Power Groove Reed** 36.65 CFM
Honda CR80 37.60 CFM
Honda CR25OR 1988/89 57.12 CFM
Kawasaki KX8O 86-87 38.17 CFM
Kawasaki KX80 1988-89 30.04 CFM
Yamaha YZ8O 86-89 38.17 CFM
Yamaha YZ80 93-94 33.63 CFM
Yamaha Banshee 350 37.28 CFM
Yamaha YSR5O all 20.00 CFM
Yamaha YZ125 1991(Factory Stock) 50.40 CFM
Yamaha YZ125 1991(Factory Modified) 47.04 CFM
Yamaha YZ125 1994(Factory 4 petal) 44.84 CFM