UMA CERAMIC CYLINDER BLOCK 58MM FORGED PISTON – R15M R15 V3,V4 MT15 AEROX NMAX V1,V2 XSR

The UMA Racing 58mm Ceramic Cylinder Block Kit is a “Premium Standard” upgrade. Unlike the 63mm kit which increases displacement, this kit maintains the stock 155cc size but replaces the factory components with race-grade materials.

It is the ultimate choice for riders who want to keep their engine “legal” for certain racing classes or maintain stock fuel economy while significantly increasing engine durability, cooling efficiency, and high-RPM reliability.

Key Features

• Stock Displacement (155cc): By keeping the 58mm bore, you avoid the legal and technical complexities of a “Big Bore” kit while gaining professional-level internals.

• Ceramic Coating: The cylinder walls are coated in a ceramic composite that dissipates heat much faster than the standard DiASil or steel liners. This keeps engine temperatures stable during long-distance touring or heavy traffic.

• Forged Piston: The kit includes a Forged Aluminum Piston. Forged pistons are much denser and stronger than the stock cast pistons, allowing them to withstand higher temperatures and higher RPM limits without the risk of “piston slap” or cracking.

• Reduced Friction: The combination of the ceramic bore and the precision-machined forged piston significantly reduces internal drag, which can result in a “freer-revving” engine and a slight increase in usable horsepower.

• Enhanced Cooling: The water jacket (coolant path) is optimized for better flow compared to the OEM block, providing an extra layer of safety against overheating.

Technical Specifications

Why choose 58mm over 63mm?

1. Reliability Over Raw Power: If you use your bike for daily commuting or long-distance “Ironman” rides, the 58mm kit offers the best longevity. It puts no extra strain on the crankshaft or rod.

2. Heat Management: It is much easier to keep a 155cc engine cool than an 183cc engine. This is ideal for tropical climates or heavy city filtering.

3. Stock ECU Compatibility: Unlike the 63mm kit, the 58mm kit can technically run on a stock ECU because the displacement hasn’t changed. However, an aftermarket ECU is still recommended to take full advantage of the forged piston’s potential.

4. Racing Regulations: For many “Stock 150/155” racing categories, you are not allowed to increase the bore. This kit allows you to have a “Racing” engine while staying within the rules.

Installation Pro-Tip

Since the displacement remains the same, you can use your stock fuel injector and stock head. However, to truly feel the difference, we recommend pairing this with a UMA Racing Camshaft (VVA) and a High-Flow Air Filter. This will allow the engine to breathe better and take advantage of the forged piston’s ability to handle high-RPM stress.

FAQs

Is 58MM good for daily use?
Yes, it is a popular balanced big bore size for riders wanting more power without going extreme.

Do I need ECU tuning?
Highly recommended for best performance and engine safety.

Is forged piston better?
Yes, forged pistons are stronger and better for performance applications.