Jims Tools 1706-3 Big Twin Breather Hole Reamer Tool

The JIMS USA 1706-3 Big Twin Breather Reamer Tool is a precision engine case repair tool designed to restore damaged breather holes on Big Twin single-cam engines. Purpose-built for professional and home mechanics alike, this tool allows you to reclaim a worn or damaged breather bore without the time and cost of a full engine teardown.

Key Features:

• Repairs damaged engine case breather holes on Big Twin single-cam models (1936–1999)
• Reams the breather bore to +.030" oversize, enabling installation of a replacement oversize breather gear
• No engine case disassembly required — perform the repair in-frame
• Completes the reaming process in under one hour
• Compatible with JIMS and S&S +.030" oversize replacement breather gears

Important Notes:

• After reaming, all aluminum chips must be thoroughly cleared from the breather bore and surrounding passages
• On early 1936–1969 crankcases, measure wall thickness at the breather hole before use to confirm the reamer will not break through into the air/oil separator cavity

JIMS USA Part Number: 1706-3. Cross-reference V-Twin Part Number: 16-0695.