Carburetor Kit - CRF250R - 2007 - Repair and Tuning

The Keyster FH-8082N Carburetor Repair and Tuning Kit is designed for the original Keihin FCR01D carburetor used on the U.S.-spec 2007 Honda CRF250R. More than a basic carburetor rebuild kit, FH-8082N combines commonly serviced fuel-system components with multiple main jets, pilot jets and four Keyster jet needle calibrations, allowing the carburetor to be repaired and its fuel mixture adjusted for the individual motorcycle.

The supplied tuning range is especially useful on a CRF250R that no longer has its original carburetor settings, or when changes in elevation, temperature, intake, exhaust or engine configuration require the fuel mixture to be adjusted. Keyster designs its tuning components as a coordinated lean-to-rich system rather than simply supplying a group of equally spaced jet sizes.

Fitment

• 2007 Honda CRF250R

Designed for the original Keihin FCR01D carburetor used on U.S.-spec 2007 CRF250R models.

Keyster Premium Nencho Kit Includes

• 1 x Chamber Gasket
• 1 x Top Cover Gasket
• 1 x Spring Seat
• 1 x Pilot Jet #41
• 1 x Pilot Jet #42
• 1 x Pilot Jet #45
• 1 x Main Jet #168
• 1 x Main Jet #171
• 1 x Main Jet #175
• 1 x Main Jet #179
• 1 x Main Jet #184
• 1 x Main Jet #189
• 1 x Jet Needle D511-L
• 1 x Jet Needle D511-S
• 1 x Jet Needle D511-R
• 1 x Jet Needle D511-RR
• 1 x Starter Jet #68
• 1 x Leak Jet #70
• 1 x Slow Air Jet #100
• 1 x Needle Jet
• 1 x Needle Valve
• 1 x Pilot Screw
• 1 x Pilot Screw Spring
• 1 x Pilot Screw Washer
• 1 x Pilot Screw O-Ring
• 1 x Needle Jet Holder
• 2 x O-Rings
• 4 x E-Clips

Keyster Tuning Range

Keyster fuel-setting kits use a lean-to-rich calibration system identified as L, S, R and related steps. The “S” component represents the standard calibration, while L moves the mixture leaner and R moves it richer.

• Main Jets:
  • #168 - LL / Leaner
  • #171 - L / Lean
  • #175 - S / Standard
  • #179 - R / Rich
  • #184 - RR / Richer
  • #189 - RRR / Richest
• Pilot Jets:
  • #41 - L / Lean
  • #42 - S / Standard
  • #45 - RR / Richer
• Jet Needles:
  • D511-L - Lean
  • D511-S - Standard
  • D511-R - Rich
  • D511-RR - Richer

This range allows changes to the low-, mid- and high-throttle fuel circuits without relying only on needle clip position or a single replacement jet size.

Factory 2007 CRF250R Carburetor Baseline

For reference, Honda specifies the following standard settings for the U.S.-spec 2007 CRF250R:

• Carburetor ID: FCR01D
• Main Jet: #175
• Slow Jet: #42
• Jet Needle: NKBT
• Needle Clip Position: 3rd groove
• Pilot Screw: 2-1/4 turns out
• Float Level: 6.0 mm (0.24 in.)

The Keyster FH-8082N includes both the factory-size #175 main jet and #42 pilot/slow jet, along with leaner and richer alternatives. It also includes the #100 slow-air jet, #70 accelerator-pump leak jet and #68 starter jet used in the original carburetor application.

D511 Jet Needle Options

Honda identifies the original U.S.-spec 2007 CRF250R jet needle as NKBT, while Keyster uses its own D511-series identification for the tuning needles supplied with FH-8082N. The D511-S is the standard calibration within the Keyster tuning system, with D511-L providing a leaner option and D511-R and D511-RR progressively richer alternatives.

Because the Keyster and Honda needle identification systems are different, the D511 codes should not be treated as Honda OEM needle numbers. Record the needle identification and clip position found in the carburetor before disassembly so the original setup can be referenced during tuning.

Honda OEM Cross-References

• Carburetor Assembly - FCR01D A: 16100-KRN-A02
• Float Valve Set: 16011-MEN-851
• Float Chamber Gasket: 16163-MEB-671
• Gasket Set: 16010-KSC-671
• Needle Jet Holder: 16165-KRN-A01
• Standard NKBT Jet Needle Set: 16203-KRN-A01
• Main Jet #175: 99101-357-1750
• Slow Jet #42: 99103-440-0420
• Slow Air Jet #100: 99104-MEB-1000
• Leak Jet #70: 99108-KRN-0700
• Starter Jet #68: 99112-KRN-0680

OEM numbers are provided for application and component-reference purposes. Keyster components use Keyster-specific calibrations and are not necessarily marked with the corresponding Honda OEM identification.

One Kit Services One Carburetor

The 2007 Honda CRF250R uses a single carburetor, so one FH-8082N kit is required to service the motorcycle.

Important Rebuild and Tuning Notes

Before disassembling the carburetor, record the existing main jet, pilot jet, jet needle identification, needle clip position and pilot-screw setting. Previous owners frequently change CRF250R jetting, so the components found in the carburetor may not match the original Honda specifications.

For a stock or near-stock motorcycle, the factory settings provide a useful starting reference. Final jetting may need to change with altitude, ambient temperature, intake or exhaust modifications, engine modifications and overall engine condition. Make tuning changes methodically and evaluate one fuel circuit at a time rather than assuming the richest available setting will provide the best performance.

The FH-8082N includes the #70 leak jet used in the accelerator-pump circuit, but the accelerator-pump diaphragm itself is not included. Inspect the diaphragm, pump passages and related components separately while the carburetor is disassembled, particularly if the motorcycle has hesitation or bogging during rapid throttle opening.

Manufactured in Japan by Keyster.