Motorcycle Valve Seat Milling Machine SUPREMA-MVC

It's used to correct the valve seat on motorcycle cylinder heads — when the seat is worn, out-of-round, or off-angle, the valve doesn't seal properly and the engine loses compression. The SUPREMA-MVC is a portable valve seat milling machine that you fix directly onto the head with an electromagnet, rotate manually with the lever, and mill the seat to the correct angle, without removing the head from a large machine. Practical and fast for motorcycle shop use.

The SUPREMA-MVC mills valve seats from 0.71 inches (18 mm) up to 1.57 inches (40 mm). It comes with two tool holder capsules (nos. 2000 and 2001) and three cutting tools (nos. 41155, 41156, and L-12 at 90°). The kit also includes nine hardened and ground pilot guide shafts in various diameters — 0.160; 0.196; 0.196; 0.214; 0.215; 0.215; 0.216; 0.216 and 0.258 inches (Ø 4.06; 4.97; 4.98; 5.43; 5.45; 5.46; 5.48; 5.49 and 6.56 mm) — to fit precisely into the valve guide of each motorcycle.

The SUPREMA-MVC is compatible with motorcycle cylinder heads that have valve seats between 0.71 and 1.57 inches (Ø 18 to Ø 40 mm) — which covers the vast majority of motorcycles on the market. Compatibility with the valve guide depends on the correct pilot guide shaft: the kit comes with nine hardened and ground shafts (from 0.160 to 0.258 inches / Ø 4.06 to Ø 6.56 mm) to handle different valve stem diameters. If the head has a seat in that range and the guide matches one of the covered diameters, the machine works.

The portable milling machine, like the SUPREMA-MVC, fixes directly onto the cylinder head via electromagnet and operates manually with the lever — ideal for motorcycle shops with limited space or lower service volume. The bench-type machine is larger, motor-driven, and usually has more angle adjustment features, making it better suited for high-volume engine rebuilders or heavier cylinder heads. The portable delivers good precision with less investment and takes up much less floor space.

First, you fit the correct pilot guide shaft into the cylinder head's valve guide — it centers everything. Then you fix the electromagnet with the column and tool holder shaft on top. You choose the right capsule and tool for the seat diameter and angle. Then just rotate the lever manually to mill. After milling, you use the vacuum gauge to check whether the valve is seating and sealing correctly. The diamond stone sharpener is used to resharpen the cutting tool when needed.

How often depends on the number of cylinder heads worked and the seat material — hardened seats wear the tool faster. The sign is when the tool starts scraping instead of cutting cleanly, or the seat finish comes out uneven. The SUPREMA-MVC already comes with a diamond stone tool sharpener included in the kit, so resharpening is done right in the shop, no sending out. There's no fixed interval: the rebuilder's own experience determines the right time.

The SUPREMA-MVC 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.