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Cylinder Head Service
Cylinder Head Service
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The CRF300L's stock cylinder head leaves a lot to be desired. Sloppy casting, non-concentric valve seats, and other shortcomings are addressed with our CNC porting service, which includes a 5-angle valve job, head-resurfacing, plus new valves and seals.
The process starts with fully automated sculpting of the intake and exhaust ports on a 5-axis CNC machine. The combustion chamber also gets contoured. Then, the stock 3-angle valve seats are given a 5-angle profile. New OEM valves and seals are included, or you can upgrade to KPMI Black Diamond Valves for an additional $60.
With this porting service, total flow (measured in CFM) is increased by an average of 12 percent with this mod, increasing power across the rev range, but especially in the midrange (see dyno chart below). We have a specific Stage 3.5 ECU tune to match this setup.
Options explained:
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Assembled head: Send us your complete, assembled head and we'll port and service it and provide new OEM or Kibblewhite valves and seals. Assembly includes setting the valve clearances using a bench engine. Turnaround time is typically 2-3 weeks. Please specify your bike's year when ordering. Option upgrade: Kibblewhite lightweight spring set.
- Replacement bare head: If you want to retain your stock head for whatever reason we'll ship you a pre-ported bare head (with new OEM or Kibblewhite valves and seals included but not installed - they go on after the spring seat is set on the guide) that you can swap your ancillary parts onto. Please specify your bike's year when ordering.
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Assembled head: Send us your complete, assembled head and we'll port and service it and provide new OEM or Kibblewhite valves and seals. Assembly includes setting the valve clearances using a bench engine. Turnaround time is typically 2-3 weeks. Please specify your bike's year when ordering. Option upgrade: Kibblewhite lightweight spring set.
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Ari Henning's work and consideration for my needs was exemplary! His attention to detail, expertise, and workmanship exceeded my expectations. I highly recommend any one considering the Big Bore project reach out to Ari!
Sprung for this at the same time along withe the big bore kit.
Anyone familiar with 550 performance ecu upgrades will understand the following. The bump in usable power for the ported and polished heads combined with the bigbore kit is like the jump from stock power to the stage 1.5 upgraded power. The jump to 3.5 tune is similar in how it completely changes the riding experience for the better.
Head looked like a quality porting job , valves and springs were top notch , every question I had was answered couldn’t be happier, Thanks
Ari Henning's work and consideration for my needs was exemplary! His attention to detail, expertise, and workmanship exceeded my expectations. I highly recommend any one considering the Big Bore project reach out to Ari!
Sprung for this at the same time along withe the big bore kit.
Anyone familiar with 550 performance ecu upgrades will understand the following. The bump in usable power for the ported and polished heads combined with the bigbore kit is like the jump from stock power to the stage 1.5 upgraded power. The jump to 3.5 tune is similar in how it completely changes the riding experience for the better.
Head looked like a quality porting job , valves and springs were top notch , every question I had was answered couldn’t be happier, Thanks