Part and Assembly Comparison

January 7, 2008 version

For clarity in the tables, I use CA for the California model 250X parts and no code for the 49-state model parts. I show only one model of the 250R, the US model, so there are no codes shown on the 250R parts. This is different than the codes that Honda uses in the Parts Catalog. If anyone from Canada, Australia, Japan, Europe, or the UK would like to send me the appropriate information for their models, I will try to include it herein.

The complete part/assembly number is made up of the prefix followed by the number within the table. The prefix is shown in each table title. For example, the 04 X cylinder head part number is 12010-KRN-672. Another example: the 06 R cylinder head part number is 12010-KRN-850.

The following parts and assemblies are compared:
Cylinder Head
Intake and Exhaust Valves
Camshaft
Tensioner Lifter Assembly
Cylinder
Left Crankcase/squirter
Piston
Carburetor Jets/needles
Fork sub-assembly
Rear Wheel sub-assembly
Swingarm sub-assembly
Rear Shock

Cylinder Head (12010-xxx-xxx)

250X

250R

04
04
04 CA

05
05 CA

06
06 CA

07
07CA

08
08CA

KRN-672
KRN-673
KSC-771

KRN-672
KSC-771

KRN-674
KSC-773

KSC-A10
KSC-A10

KSC-A10
KSC-A10

round intake ports (up to 5013824)
round intake ports (5013825 and above)
round intake ports

round intake ports
round intake ports

round intake ports, new seat material
round/oval? intake ports, new seat material

49-state and CA now both
use the same head

 
 

04
04
04

05
 

06
 

07
 

08
 

KRN-670
KRN-671
KRN-672

KRN-730
 

KRN-850
 

KRN-A00
 

KRN-A10
 

round intake ports (up to 2006059)
round intake ports
round intake ports

oval intake ports
 

oval intake and exhaust ports, new seat material
 

intake and exhaust ports futher downsized
 

intake port divider has been extended
exhaust valve guides changed for new ex valves

Note: All X and R heads are interchangeable between models and years.

 

Intake Valves (14711-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

 
 

 
 

 
 

 
 

 
 

04
 

05
 

06
 

07
 

08
 

KRN-670
 

KRN-670
 

KRN-670
 

KRN-670
 

KRN-670
 

 
 

 
 

 
 

see note below
 

see note below
 

Note: All X and R intake valves for all years are the same.
Although the 07 R intake valves are unchanged, the valve lifters (buckets), intake valve springs, and valve spring retainers are new to match the new '07 cam.
Although the 08 R intake valves are unchanged, the intake valve springs and valve spring retainers are new to match the new '08 cam.

 

Exhaust Valves (14721-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

 
 

 
 

 
 

 
 

 
 

04
 

05
 

06
 

07
 

08
 

KRN-670
 

KRN-670
 

KRN-670
 

KRN-670
 

KRN-A10
 

 
 

 
 

 
 

see note below
 

new exhaust valves
see note below

Note: All X and R exhaust valves for all years except '08 are the same.
Although the 07 R exhaust valves are unchanged, the exhaust valve springs and valve spring retainers are new to match the new '07 cam.
In addition to the 08 R exhaust valves change, the exhaust valve springs, valve spring retainers, cotters, and valve guide seals are new.

 

Camshaft (14100-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSC-670
KSC-770

KSC-670
KSC-770

KSC-670
KSC-770

KSC-670
KSC-770

KSC-670
KSC-770

 
 

 
 

 
 

 
 

 
 

04
 

05
 

06
 

07
 

08
 

KRN-670
 

KRN-730
 

KRN-670
 

KRN-A00
 

KRN-A10
 

 
 

 
 

back to the 04 cam
 

new cam
 

another new cam
 

Note: All X camshafts for all years are the same, according to model.

 

Tensioner Lifter Assembly (14520-xxx-xxx)

250X

250R

04
04 CA
04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KRN-670
KRN-670
KRN-671
KRN-671

KRN-671
KRN-671

KRN-671
KRN-671

KRN-671
KRN-671

KRN-671
KRN-671

up to 5004902
up to 5004902
5004903 and above
5004903 and above

 
 

 
 

 
 

 
 

04
04
 
 

05
 

06
 

07
 

08
 

KRN-670
KRN-671
 
 

KRN-671
 

KRN-671
 

KRN-671
 

KRN-671
 

up to ?
? and above
 
 

 
 

 
 

 
 

 
 

Note: The tensioner lifter assembly was probably redesigned to fix the camshaft-gear-jumping problem.

 

Cylinder (12100-xxx-xxx)

250X

250R

04
04 CA
04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KRN-670
KRN-670
KRN-671
KRN-671

KRN-672
KRN-672

KRN-730
KRN-730

KRN-730
KRN-730

KRN-730
KRN-730

up to 5011470
up to 5011470
5011471 and above
5011471 and above

 
 

changed for oil squirter redesign
changed for oil squirter redesign

 
 

 
 

04
04
04
 

05
 

06
 

07
 

08
 

KRN-670
KRN-671
KRN-672
 

KRN-730
 

KRN-730
 

KRN-730
 

KRN-730
 

up to 2054823
2054824 and above
later
 

changed for oil squirter redesign
 

 
 

 
 

 
 

Note: The original 04 R cylinder skirts broke under high RPM loads; redesigned mid-year. The change was made to the X as well.

 

Left Crankcase/squirter (11200-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSC-670
KSC-770

KSC-670
KSC-770

KSC-671
KSC-671

KSC-A10
KSC-A10

KSC-A20
KSC-A20

 
 

 
 

changed for oil squirter redesign
changed for oil squirter redesign

changed for tranny bearing change
changed for tranny bearing change

changed for crankcase bearing change
changed for crankcase bearing change

04
 

05
 

06
 

07
 

08
 

KRN-670
 

KRN-730
 

KRN-850
 

KRN-A00
 

KRN-A10
 

 
 

changed for oil squirter redesign
 

another change
 

changed for tranny bearing change
 

changed for crankcase bearing change
 

 

Piston (13101-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KRN-670
KRN-670

KRN-670
KRN-670

KRN-670
KRN-670

KSC-850
KSC-850

KSC-850
KSC-850

 
 

 
 

 
 

from 250R
pin and rings are different, also

 
 

04
 

05
 

06
 

07
 

08
 

KRN-670
 

KRN-670
 

KRN-850
 

KRN-850
 

KRN-A10
 

 
 

 
 

pin and rings are different, also
 

 
 

new 13.1 high compression piston
 

Note: All X and 04/05 R pistons are the same. The stroke and the head combustion chamber shape are the same for these models, thus the compression ratio is the same for all of these models. The various Service Manuals all show 12.9 : 1. So also shows the 06 R Service Manual.

 

Carburetor assembly and jets/needles (16100-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSC-671
KSC-771

KSC-671
KSC-771

KSC-673
KSC-773

KSC-A22
KSC-L12

KSC-A22
KSC-L22

55, 40, 130, NCVT (leak, pilot, main, needle)
65, 40, 130, NCYU

55, 40, 130, NCVT
65, 40, 130, NCYU

55, 40, 130, NCVT
65, 40, 130, NCYU

60, 42, 130, NLAT
55, 42, 132, NLBU

60, 42, 130, NLAT
55, 42, 132, NLBU

04
 

05
 

06
 

07
 

08
 

KRN-671
 

KRN-731
 

KRN-851
 

KRN-A02
 

KRN-A12
 

70, 40, 160, NCYR (leak, pilot, main, needle)
 

70, 42, 172, NCYQ
 

55, 40, 172, NHFS
 

70, 42, 175, NKBT
 

70, 42, 188, NMGU
 

 

Fork sub-assembly (51480-xxx-xxx and 51580-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSC-003
KSC-003

KSC-003
KSC-003

KSC-A01
KSC-A01

KSC-A01
KSC-A01

KSC-A21
KSC-A21

 
 

 
 

damper changes, less axle offset
damper changes, less axle offset

 
 

? don't know what's different
? don't know what's different

04
 

05
 

06
 

07
 

08
 

KRN-003
 

KRN-711
 

KRN-841
 

KRN-J01
 

KRN-A11
 

 
 

damper changes, less axle offset
 

valving
 

damper changes
 

higher spring rate, new damper assy
 

 

Rear Wheel sub-assembly (42650-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSC-000
KSC-000

KSC-000
KSC-000

MEY-000
MEY-000

MEY-000
MEY-000

KSC-A20
KSC-A20

 
 

 
 

lighter
lighter

 
 

lighter rim
lighter rim

04
 

05
 

06
 

07
 

08
 

KRN-000
 

KRN-710
 

KRN-710
 

KRN-710
 

KRN-A10
 

 
 

lighter
 

 
 

 
 

lighter rim
 

 

Swingarm sub-assembly (52200-xxx-xxx) (including all attached parts)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSR-J00
KSR-J00

KSR-J00
KSR-J00

KSC-A00
KSC-A00

KSC-J00
KSC-J00

KRN-A10
KRN-A10

 
 

 
 

lighter
lighter

from 250R, lighter chain guide
from 250R, lighter chain guide

from '08 250R
from '08 250R

04
 

05
 

06
 

07
 

08
 

KSK-000
 

KRN-710
 

KRN-840
 

KRN-J00
 

KRN-A10
 

 
 

lighter
 

? don't know what's different
 

lighter chain guide
 

? don't know what's different
 

 

RR Cushion Assembly aka Rear Shock (52400-xxx-xxx)

250X

250R

04
04 CA

05
05 CA

06
06 CA

07
07 CA

08
08CA

KSC-003
KSC-003

KSC-003
KSC-003

KSC-A01
KSC-A01

KSC-A11
KSC-A11

KSC-A11
KSC-A11

 
 

 
 

lighter
lighter

? don't know what's different
? don't know what's different

 
 

04
 

05
 

06
 

07
 

08
 

KRN-671
 

KRN-731
 

KRN-851
 

KRN-851
 

KRN-A11
 

 
 

lighter
 

valving
 

 
 

? don't know what's different
 

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