This is the OS Speed B2103 Type S engine with OS T2100SC exhaust system.

The OS Speed B2103 Type S engine is a 3-port long-stroke engine that offers a high torque at mid-low range with a sweet delivery and low consumption. The crankcase, the crankcase cap and the carburetor feature a new design. The new DLC-coated crankshaft has two tungsten counterweights for smooth rotation and better balancing. The B2103 Type S comes with a low–profile cooling head to provide better drivability and also vertical fins on the top to improve heat dissipation. An O-ring between the cooling head and the combustion chamber insert reduces vibrations protect against dirt thanks to a better sealing. The new 22D carburetor guarantees high response and smooth acceleration.

Features:

• The long-stroke off-road engine put a high value on torque in low-middle range with smooth operation and better fuel mileage
• The crankcase, carburetor and cover plate, and inner head are designed new.
• All the parts are interchangeable to those of TYPE R’s.
• High vertical finned low-profile cooling head for improving the drivability and better heat dissipation
• The new DLC coated crankshaft has two tungsten counter weights for smooth rotation and the best balance
• A newly designed 3-port cylinder& piston set
• The inner head with a silicon O-ring for reducing vibration and preventing dust
• A newly designed 22D carburetor, which produces high response and smooth acceleration
• Replaces Speed Spec III
• Includes the OS T2100SC exhaust system

Technical specifications:

• displacement 3.49cc
• bore 16.27mm
• stroke 16.80mm
• rpm 4000-42000 rpm
• max output 2.64hp/34000 rpm
• weight 347gr
• exhaust T2100SC
• port 3-port