ProBld GY6 Engine Case Boring Tool - 54mm Stud Spacing

Case boring doesn’t have to be stressful — this ProBld tool lets you open up your GY6 A engine cases for larger cylinders with clean precision. Just bolt it on, chuck up a drill, and adjust to your desired bore size.

The Details

Designed specifically for GY6 A (54mm stud spacing) engine cases, this boring tool keeps the cut centered and consistent, helping you safely clear material for big-bore cylinders. Run your drill with the clutch engaged and take shallow passes to maintain control. The stainless hardware and adjustable guide arms make this a strong, reusable tool for builders who love clean work.

Important Things to Note

• For 54mm stud spacing only (GY6 A cases)
• The crankshaft must be removed before use
• Cut in small increments — do not remove too much material at once
• Requires a handheld drill with clutch
• This demonstration video is for reference only — it does NOT show the ProBld tool

What's Included

• ProBld GY6 case boring tool assembly
• Adjustable boring guide arms
• Mounting hardware for case setup