Super Head 4V+R Bore Up Kit 145cc CT125 Monkey 125 GROM

【SP武川 01-05-0644 Superhead 4V+R Bore Up Kit 145cc for CT125, Monkey 125, GROM Engine Parts Takegawa】
■Product Description
By increasing the number of intake and exhaust valves to two each, the valve curtain area has been further expanded, enabling higher intake and exhaust efficiency than with large-diameter 2-valve engines.
Furthermore, the head shape is designed to balance the center plug, valve挟み角 (valve included angle), combustion chamber shape, and port shape, all of which are a result of the 4-valve configuration. This allows for higher output and achieves the sustained high-revving power characteristics that are a hallmark of the Superhead.
By adopting a 1-cam, 4-valve design, we were able to achieve the lightest and most compact design possible, while simultaneously condensing the performance expected of the strongest SOHC head.

■Detailed Description
●Adopts bearing-integrated roller rocker arms, similar to genuine parts.
Reduces friction resistance with the camshaft, and the roller bearings integrated into the rocker arms allow for smooth tracking of the cam profile from low to high revolutions.
●Valves
Intake: 21.5mm x 2 / Exhaust: 18.5mm x 2
Valve stem shaft diameter: 4.0mm for both intake and exhaust.
●Valve Springs
Uses unequal pitch (two-stage pitch) single valve springs, which reduces surging at high revolutions. The ports are optimized to match SP Takegawa's big throttle body manifold.
Additionally, by simultaneously installing an SP Takegawa big throttle body manifold, a smooth and unobstructed intake effect from the big throttle body to the combustion chamber is achieved, maximizing the performance of the cylinder head.
The original SP Takegawa cylinder head design blends well with the vehicle's style, enhancing the custom image of the vehicle.
Furthermore, the inspection cover and L. cylinder head side cover are made of barrel-polished die-cast aluminum.
The oil tower on the R side of the cylinder head also features machined aluminum with silver anodizing.
Various covers and the oil tower, which boast excellent dress-up effects, elegantly adorn the cylinder head.
●M8 Spark Plug
An M8 spark plug is adopted due to the optimal valve included angle resulting from the 4-valve configuration and the compact head design.
●Auto Decompression Camshaft (10/10D)
The camshaft is supported by ball bearings at both ends, reducing friction resistance in the camshaft journal area.
●Auto Decompression Mechanism
Reduces the force required for kick-starting and the load on the transmission when starting the engine, allowing for smooth engine starting even with large displacements.
●Cylinder
Adopts an aluminum cylinder with an iron sleeve.
Bore diameter 54mm. Stroke 63.1mm (normal). Compression ratio 12.0:1.
The cylinder can be fitted with an SP Takegawa M5 temperature sensor, allowing for measurement of cylinder temperature by purchasing a separate thermometer (Compact LED Thermometer with M5 Temperature Sensor).
●Piston
The piston itself is precisely machined from cast aluminum, resulting in a lightweight yet highly rigid finish.

■Compatible Models
HONDA
CT125 (JA65-1000001～1099999)
Monkey 125 (JB03/JB05-1000001～)
GROM (JC92-1000001～1099999)

■Notes
※Image is for illustration purposes. Includes products of different sizes and colors.
※Product design and specifications are subject to change without notice. Please be aware of this.
※When installing the Superhead 4V+R Bore Up Kit, simultaneous installation of the FI-CON TYPE-X (injection controller) is required.
※As the displacement will exceed 125cc, it cannot be driven on public roads under light motorcycle registration (Type 2). It is for competition use only.
※The installation of SP Takegawa's bore-up kit significantly increases engine output and torque, which increases stress such as twisting and deflection on the crankshaft. SP Takegawa recommends simultaneous installation of a crankshaft support adapter to reduce the load on the crankshaft. The crankshaft support adapter adds support with a ball bearing at the end of the crankshaft flywheel side, suppressing twisting and deflection and improving crankshaft durability.
※This product is made to order, so cancellations are not accepted after an order is placed.
※As this product is made to order, it takes time for delivery. Also, please note that the manufacturer may discontinue the product or change specifications without prior notice. Thank you for your understanding.