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Super Head 4V +R 138cc SCUT Kit w/ 3 Point Supported Crankshaft - Honda CRF50/CRF70/Monkey/Gorilla

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  • $ 1,749.95


Super Head 4V +R 138cc SCUT Kit w/ 3 Point Supported Crankshaft*

CRF50F (AE03-1400001~) 
: XR50R (AE03-1000001 ~) : CRF 70F (DE 02-1700001~) 
: XR 70 R (DE 02-1300 001 -)
: 12V Monkey · Gorilla (Z50J-2000001~ / AB27-1000001~1899999) 

■ Features of Super Head 4V + R (1 cam 4 valve)

Compared to the large diameter two valves of our super head + R, by setting each two intake valves and two exhaust valves, the valve curtain area can be further enlarged, and the intake and exhaust efficiency is increased to two or more large valves It was possible to increase it. In addition, due to the head shape designed by balancing the center plug formation, valve pinching angle, combustion chamber shape, port shape, with the introduction of 4 valves, it is possible to achieve high output, which is also the greatest feature of Superhead It achieves sustainable output characteristics in the rotation range. 
By adopting 1 cam 4 valve, we were able to make light and compact as much as possible, at the same time condensing the performance as SOHC head strongest head. 

New shape Super head 4 valve + R body 
The cylinder head shape with roundness well matches the monkey style, and it can enhance the custom image of the vehicle. 
Also, each head cover made by die casting with barrel polishing produces a cylinder head beautifully. 

Valve features 
Valve diameter Intake: 21.5 mm × 2 / Exhaust: 18.5 mm × 2 
Valve stem Shaft diameter: 4.0 mm for both intake and exhaust 
Valve spring 
Prevent surging at high rotation by adopting unequal pitch. 

Characteristics of the IN / EX port The 
optimal port diameter is adopted for the port diameter according to our company's three-dimensional shape manifold. Moreover, simultaneous installation with the three-dimensional shape manifold enables smooth inhalation effect from the carburetor to the combustion chamber without resistance, and maximizes the performance of the cylinder head. 

Adoption of roller rocker arm
By adopting the roller rocker arm, we can draw out the output performance of the super head + R to the utmost, making it possible to maintain the output in the high rotation range which is also characteristic of the roller rocker arm and the output of the middle and high speed range. The roller rocker arm reduces the frictional resistance with the camshaft occurring in the slipper type rocker arm (genuine part type), and 
the roller bearings built in the rocker arm smoothly follow the cam profile from low rotation to high rotation. 

M8 Spark Plug 
4 Adopting M8 spark plug in conjunction with the optimum valve pinch angle and valve head size compact by valving.

 Hollow cam shaft (auto decompression mechanism)

The camshaft adopts both end ball bearing support and reduces the frictional resistance of the camshaft journal part. Since the optional camshaft is set in addition to the attached camshaft, it can be exchanged according to the intended use and enjoy running performance. 
Attached camshaft: 20 / 25D 
Auto Decompression Mechanism It 
reduces the kickstart force and mission burden at engine start, enabling smooth engine start even with large displacement.


 Ceramic plating cylinder / piston

The 138cc SCUT structure is patented. 
Bore diameter 57 mm 
Adopted all-aluminum ceramic plated cylinder excellent in durability, airtightness, heat dissipation. Temperature sensor mounting part is equipped as standard on the cylinder. You can measure the cylinder temperature by purchasing our thermometer built-in meter or thermometer. 
For SCUT 138 cc: C1 adapter + M5 temperature sensor  
Scut cylinder is equipped with oil jet mechanism (patent pending) 
Oil jet cylinder disassembles the crankcase and disassembles the crankcase, parts for oil injection hole machining or oil injection Without adding, it is a cylinder that can inject oil to cylinders, pistons, etc. by changing cylinders only. 
By providing the oil injection hole directly on the inner surface of the cylinder, it is possible to inject oil without interrupting the piston skirt portion and the inner wall of the piston during engine start, and it is possible to perform efficient lubrication and cooling. 
The 138 cc adopts a cast piston. Molybdenum coat is applied to the piston skirt part for good initial familiarity.


 3 point supported crankshaft

The crankshaft body is balanced cut processing for low vibration countermeasure, and it is made lightweight. By further supporting the 3B crankshaft with 3 points, the runout of the crankshaft was further reduced and durability was improved. 
Comparison with 2B crank In the 
conventional crankshaft, the bearing journal part was supported at two points in two places in the crankcase, but the three point supported crankshaft is equipped with two parts inside the crankcase and an aluminum generator It will be connected to a bearing built in the cover and will be supported at three points. Also, by applying special surface treatment to the crank taper part, raising the flywheel mounting screw from M10 to M12 and increasing the tightening force, the gripping of the contact surface with the flywheel etc. has been drastically reduced. 
3 point supported crank shaft exclusive crankcase Bearing In 
order to prevent durability increase and output reduction of the crankcase, the press fit type is adopted for the bearing on the right crankcase side, and play in the thrust direction of the crank journal is reduced. 
Stroke amount 54 mm


Normal generator cover can not be mounted on 3 point supported crankshaft. 
The three point supported crankshaft needs to press fit the right journal bearing into the crankcase. 
Special tool crankshaft installer & puller set is sold at our company. Part No. 00-01-0352 When installing 
124 cc / 125 cc / 138 cc, the length of the engine becomes long, and in the normal front fork, normal top bridge & stem, the engine interferes with the tire, so it is necessary to change around the front. 

In case of Monkey · Gorilla 
We recommend simultaneous installation of various front fork kits made by our company. 

For CRF50F / XR50R / CRF70F / XR70R 
We do not sell front fork kits etc at our company. Also, although external frame and front fork kit are on sale, our company does not confirm installation by simultaneous mounting. Ni 関 Shimashite wearing a vehicle, please go at your own risk. 
Our company Digigross muffler can not be installed at the same time.