
Manufacturer reference: 60-60670
Kibblewhite C674 valve guide, designed for head preparation and refurbishment on motocross machines. Made in the USA, this C674 bronze (manganese) guide offers easy machining: it bores quickly and finishes smoothly with Kibblewhite ball hones, even when mounted on an electric or cordless drill. Ideal for mechanic riders who want to renew the intake and exhaust guides without excessive machining constraints.
These guides meet the same strict KPMI® tolerances, while exhibiting lower strength and durability compared to premium C630 guides (nickel-aluminium bronze). They are preferred when seeking easier fitting on the boring/honing machine and controlled seating of the valve seats. Particularly suitable for SUZUKI RM-Z 450 (RL42A) 2007 heads and other compatible motocross machines.
Workshop tip: check play and concentricity after boring and proceed with gradual honing to ensure clean and reliable valve guidance over time.