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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