Honda Exhaust Valve Guide (Over Size) 12205-PNA-305. Restore proper valve-to-guide clearance with the Honda Exhaust Valve Guide (Over Size). This genuine Honda replacement is made for cylinder head rebuilds where the original guide bore has been reconditioned and now requires an over size guide to achieve the correct press fit. When installed and sized correctly, it helps keep the exhaust valve aligned and moving smoothly, supporting consistent sealing, stable compression, and long-term durability.. Key Features. Genuine Honda valve guide for dependable fit and material quality. Over size design for heads that have been machined to accept an over size guide. Helps maintain correct valve stem support and alignment. Supports improved oil control by reducing excess guide clearance. Ideal for rebuilds addressing worn guides, poor sealing, or uneven valve wear. Why It Matters. Exhaust valve guides work under extreme heat and can wear over time. Excess clearance can contribute to oil consump