Motorcycle Valve Seat Milling Machine SUPREMA-MVA

The motorcycle valve seat milling machine is used to machine (mill) the seat where the valve rests in the cylinder head. When the seat is worn or out of angle, the valve doesn't seal properly and the engine loses compression. The Chinelatto SUPREMA-MVA mills seats from 0.71 to 1.57 inches (Ø 18 to Ø 40 mm), already including a pneumatic motor, a vacuum gauge to check valve seating, and 9 pilot guide shafts for different valve guides.

The SUPREMA-MVA mills valve seats from 0.71 to 1.57 inches (Ø 18 to Ø 40 mm) — a range that covers the vast majority of motorcycle cylinder heads on the market. It comes with 2 toolholder capsules (no. 2000 and 2001) and 3 cutting tools (no. 41155, 41156, and L-12 at 90°). The kit ships ready to work, with no need to purchase separate tooling to get started.

The SUPREMA-MVA is designed for motorcycle cylinder heads in general. Compatibility depends on the seat diameter (0.71–1.57 inches / Ø 18–40 mm) and the valve guide diameter, because the machine uses hardened and ground pilot guide shafts as the centering reference. The kit includes 9 shafts in diameters 0.160 / 0.196 / 0.196 / 0.214 / 0.215 / 0.215 / 0.216 / 0.216 / 0.258 inches (Ø 4.06 / 4.97 / 4.98 / 5.43 / 5.45 / 5.46 / 5.48 / 5.49 / 6.56 mm), covering most domestic and imported popular motorcycles.

On a manual milling machine, the operator has to hold and align the cylinder head by hand during the job, which increases the risk of vibration and angle deviation. On a milling machine with an electromagnet — like the SUPREMA-MVA — the electromagnet clamps the assembly (column + toolholder shaft) to the cylinder head, providing greater stability during milling. The result is a more uniform valve seat, which improves valve sealing and the service life of the repair.

The process starts by fitting the correct pilot guide shaft into the valve guide of the cylinder head — it centers the tool on the seat. The electromagnet is activated to lock the column in place. The pneumatic motor (connected to compressed air) rotates the toolholder capsule with the cutting tool, which removes material from the seat until the correct angle and finish are achieved. Finally, the vacuum gauge tests the valve seating: if the vacuum holds, the seal is good.

The main maintenance for the cutting tool is resharpening. The SUPREMA-MVA already comes with a tool sharpener equipped with a diamond stone, so the shop technician can resharpen the tool in-house without sending it out. In addition, the pilot guide shafts are hardened and ground for long service life, but they need to be kept clean and free of burrs to ensure correct centering. The pneumatic motor requires lubrication according to the manufacturer's instructions.

The SUPREMA-MVA is quoted on demand, and pricing varies with each customer's needs, including accessories, tooling and optional features. With in-house technology developed by Chinelatto in Brazil since 1962, you can count on responsive support from our technical team. Spare parts: many are kept in stock and the others are manufactured within a reasonable lead time. Request a quote at chinelatto.com.br/contact — our sales team will contact you very soon.