Exhaust stud with Allen head no need to double nut these. Insert with Allen or hex head and use Loctite. Super strong perfect for those big bore kits. Use M6 for Honda Ruckus 49cc. Usually GY6 big bore heads use M8 such as TAIDA or NCY. Please check your headfirst.
|Dimensions||3 × 2 × 0.25 in|
1/4 (6MM), 5/16 (8MM)