This kit part features the Desmodromic Twin Cam 4V cylinder head.
Desmodromic Twin Cam 4V Head Features
Desmodromic Engine (Forced Valve Opening and Closing Mechanism)
In most motorcycles, the intake and exhaust valves are opened and closed by the camshaft and valve springs.
The Desmodromic mechanism uses a specially shaped camshaft and rocker arm to forcibly open and close the valves. Since there is no valve spring, there is no surging at high rpm and the friction related to the camshaft drive is very low.
The SP Takekawa Desmodromic Twin Camshaft 4V is designed with 8 rocker arms and 2 camshafts skillfully arranged like a precision machine within the limited stud bolt positions of the Monkey.
The Desmodromic mechanism, combined with SP Takekawa's cylinder head development technology, achieves the highest level of intake and exhaust efficiency and engine performance.
The Twin Cam Desmodromic 4V offers the highest power output and engine response that you have ever experienced.
Valve diameter
The exhaust port is located in the same position as the Monkee (carburetor model), so you can use the stock lineup of exhausts instead of the special exhausts.
Machined aluminum cylinder head cover
All cylinder head covers are machined from aluminum and anodized silver for superior corrosion resistance.
The anodizing process emphasizes the machined aluminum parts and gives the cylinder head a beautiful appearance.
Breather union is included when using a breather hose.
M8 Spark Plug
In line with the optimal valve pinching angle and head compactness due to the 4-valve design, the M8 spark plug is used.
Rocker Arm / Hollow Camshaft
Rocker arm (forced valve opening/closing mechanism)
Without valve springs, the camshaft forces the valves to open and close.
In contrast to the valve spring type, the rocker arm (forced valve opening/closing mechanism)
forcibly opens and closes the valves with the camshaft. (
Hollow camshaft
The camshaft of the forced valve opening/closing mechanism has two independent camshafts, one for opening and one for closing. The camshaft of the forced valve opening/closing mechanism is equipped with camshafts that perform independent actions for "open" and "closed".
The camshaft journals are supported by ball bearings on both ends to reduce frictional resistance during start-up and at low speeds.
The camshafts included in the kit are the recommended camshafts for each displacement.
Ceramic Plated Cylinder/Piston
124cc HA Cylinder
All aluminum ceramic plated cylinder is used for durability, airtightness and heat dissipation.
The cylinder comes stock with a temperature sensor mounting area.
The cylinder temperature can be measured by SP Takekawa's built-in thermometer or by purchasing a thermometer.
124cc HA Cylinder: M5 Temperature Sensor
124cc uses forged pistons
■ 2-Point Crankshaft
To accommodate high power engines, the journal bearing of the long stroke crankshaft (54mm stroke) is specially designed with a larger bore. The crankshaft is equipped with a special bearing with a larger inner diameter.
This allows the shaft diameter to be increased from 20mm to 22mm, which is where the crankshaft stress is concentrated.
The crankshaft is also treated with a special surface treatment to further increase durability.