KPMI +0.001" Oversized Cast Iron Valve Guide - Evolution Intake & Exhaust - Harley Evolution 1987-1999
About KPMI
Kibblewhite Precision Machining supplies valves, valve springs, guides and complete top-end kits used by professional V-twin engine builders. Its black diamond valves and spring kits are a standard specification on high-lift cam builds.
Address wear in your Harley Evolution cylinder heads with KPMI +0.001" oversized cast iron valve guides. These guides are engineered to restore proper valve stem clearance in cylinder heads that have experienced wear, ensuring optimal valve train function. Designed for both intake and exhaust positions, they are a key component for rebuilding your Evolution motor.
Why riders pick this
- Cast iron construction for robust durability
- +0.001" oversized for worn valve guide bores
- Works for both intake and exhaust valves
- Machined to factory OEM specifications
- Restores valve train precision and reduces oil consumption
When the original valve guide bores in your Evolution cylinder heads wear, a standard size replacement may not provide the necessary press fit. KPMI oversized cast iron valve guides allow for precise machining of the head to achieve correct valve stem clearance, which is critical for preventing oil seepage and maintaining consistent compression. This ensures a long-lasting and reliable top-end.
Built for Worn Cylinder Heads
- Durable cast iron construction for dependable service
- +0.001" oversized for optimal fit in worn bores
- Compatible with both intake and exhaust valve positions
- Machined to factory specifications as a direct OEM replacement
Revitalize Your Evolution Engine
Incorporating oversized valve guides like these KPMI units is crucial for bringing worn Evolution cylinder heads back to spec. Proper valve guide installation, often part of a complete valve job, ensures that your 1987-1999 Harley Evolution engine performs reliably and efficiently. This helps prevent further wear on valves and seats, extending the life of your motor.
Specifications
- Brand: KPMI
- Manufacturer Part #: 20-4321C
- Material: Cast iron
- Oversizing: +0.001 in
- Length: 1.65 in
- Weight: 0.04 lbs
Common questions
What is the purpose of a +0.001" oversized valve guide?
The +0.001" oversizing is designed to compensate for wear in the cylinder head's original valve guide bore. This allows a machinist to ream the bore to a precise size, ensuring a tight, correct press fit for the new guide.
Is this valve guide compatible with Twin Cam or Milwaukee-Eight engines?
No, these KPMI valve guides are specific to Harley-Davidson Evolution engines from 1987-1999. Twin Cam and Milwaukee-Eight engines require different part numbers.
Can I use this guide for both intake and exhaust valves?
Yes, this KPMI +0.001" oversized cast iron valve guide is designed to fit both the intake and exhaust valve positions on 1987-1999 Harley Evolution cylinder heads.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | KPMI |
| TYPE | Engine |
| SKU | 191-57004C |
| WEIGHT | 0.04 lb |
