BBR Tuning 49cc 4-Stroke Motorized Bicycle Intake Manifold Upgrade &ndash; Install Any 2-Stroke Carburetor Directly To A 4 Stroke INCREASES PERFORMANCE: Since there are few upgrades for 4-stroke motorized bicycles being able to swap out your non adjustable stock carburetor to a high performance 2-stroke carburetor is huge. Be able to a just fuel to air ratio as well as jetting gives your engine huge potential for increased torque and top speed. HEAVY DUTY: This intake manifold is machine from aircraft grade billet aluminum and designed to provide clean air flow to your engines cylinder head resulting in a smoother more efficient running engine. EASY INSTALLATION: Installation couldn't be easier: just remove the stock carburetor from your 4-stroke engine block, mount the new manifold on top of the stock spacer and gasket, then bolt on the 2-stroke carburetor you want to use UNIVERSAL FIT: Works with most 49cc motorized bicycle engine kits such as the Flying Horse 5G and Huasheng 142f 4G and 7G. Compatible carburetors are the NT Carburetor, Speed Carburetor, high performance carburetors and Runtong/ Runtong. It's not compatible with CNS carburetors. INCLUDED COMPONENTS: 1x 40mm Stud Spaced Billet Aluminum BBR Tuning 4-Stroke Intake Manifold