KOSO NORTH AMERICA - MC623000 - Four-Valve Head Kit — Big Bore - '14-'21 Honda Grom 125, Monkey
Koso's Four-Valve Head Kit is the piece that completes a Big Bore build on '14-'21 Honda engines, swapping in a four-valve design that increases airflow and performance over the stock two-valve head. The kit includes a forged piston along with stainless steel 24mm intake and 20mm exhaust valves for more power and torque. A proper exhaust system needs to be paired with it to prevent back pressure and excess heat from building up.
Features
- Ideal engine part to complete Koso's big bore kit
- Unique four-valve design increases air flow and performance
- Provides more power and torque
- Features a forged piston, stainless steel 24 mm intake valves and 20 mm exhaust valves
- Proper exhaust system must be used to prevent re-flow pressure and heat.
Specs
- Engine Type: 4-Stroke
- Product Name: Cylinder Head Kit
- Units: Kit
- Displacement: 170 cc
- Style: Big Bore
- Compression Ratio: 12.3:1
- Features: Head Kit Only
- Riding Style: Street
- Material: Stainless Steel
- Type: 4 Valve
Frequently Asked Questions - KOSO NORTH AMERICA - MC623000 - Four-Valve Head Kit — Big Bore - '14-'21 Honda Grom 125, Monkey
How do I know if this part fits my vehicle?
Check the fitment information listed on this page against your exact year, make, model, and (where applicable) trim, engine size, or configuration. If your exact vehicle isn't listed, or you're not sure, use the product chat on this page or contact our support team before ordering - we're glad to help confirm fitment.
What does it mean if a product is listed as universal fit?
Universal fit means the product is designed to work across a range of vehicles, not that it's guaranteed to fit every one. Compare the listed measurements, mounting requirements, and connector or hardware specs against your specific vehicle before ordering, since some installations may need additional hardware or minor fabrication.
Where can I find installation instructions for this product?
General installation notes are provided above where available. For detailed step-by-step instructions, refer to the manufacturer's documentation included with the product, or use the product chat on this page for questions about difficulty, required tools, or whether professional installation is recommended.
What if I have more questions about this product?
Use the product chat on this page for fitment, specs, installation, and compatibility questions, or contact our support team directly for help before you order.
