HRC Setting Data & Maintenance Information
RS125R Parts Combination according to model years
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If used machines are bought, previous owner’s specifications should be fully checked whether they are bought from private owners or retailers.
Since the RS racers have had improvements year by year, they are different in specifications depending on model years even if they have similar exterior appearance. Accordingly, before installing parts, manufacture years and parts combination according to years should be confirmed. Wrong combination would lead to degraded performance and failures.
Shown below are parts combinations according to manufacture year for the RS125R.
Since the RS racers have had improvements year by year, they are different in specifications depending on model years even if they have similar exterior appearance. Accordingly, before installing parts, manufacture years and parts combination according to years should be confirmed. Wrong combination would lead to degraded performance and failures.
Shown below are parts combinations according to manufacture year for the RS125R.
Parts combination for RS125R
Parts name Criteria '97 '98 '99 '00 '01
Cylinder Cylinder stamp Head No.6 Head No.7 Head No.8 Head No.9 Head No.0
Cylinder head Plug seating surface Plateau Plateau Plateau Plateau Recess
ECU Type No. CI662C CI708 CI708 CI708 CI708B
Carburetor Carburetor stamp 09A 09A 09D 09J
Parts name Criteria '97 '98 '99 '00 '01
Cylinder Cylinder stamp Head No.6 Head No.7 Head No.8 Head No.9 Head No.0
Cylinder head Plug seating surface Plateau Plateau Plateau Plateau Recess
ECU Type No. CI662C CI708 CI708 CI708 CI708B
Carburetor Carburetor stamp 09A 09A 09D 09J
Criteria for each part
1) Cylinder
Cylinders should be identified by the first digit of the 8-digit stamped numbers placed to the left when the exhaust side is faced forward.
Basically, manufacture year minus one (first digit).
2) Cylinder head
Photo below to the left shows a cylinder head with elevated plug-seating surfaces for 1997 through 2000 year model.
Photo below to the right shows a cylinder head with recessed plug-seating surface for the 2001 year model.
Viewing from the combustion chamber side, plug-seating surfaces are opposite each other (2001 year model has elevated seating surface).
Cylinder head with elevated plug-seating surfaces for 1997 through 2000 year model
Cylinder head with recessed plug-seating surface for the 2001 year model.
1) Cylinder
Cylinders should be identified by the first digit of the 8-digit stamped numbers placed to the left when the exhaust side is faced forward.
Basically, manufacture year minus one (first digit).
2) Cylinder head
Photo below to the left shows a cylinder head with elevated plug-seating surfaces for 1997 through 2000 year model.
Photo below to the right shows a cylinder head with recessed plug-seating surface for the 2001 year model.
Viewing from the combustion chamber side, plug-seating surfaces are opposite each other (2001 year model has elevated seating surface).
Cylinder head with elevated plug-seating surfaces for 1997 through 2000 year model
Cylinder head with recessed plug-seating surface for the 2001 year model.
'97 -'00 cylinder head with plateau shape spark plug-seating surface.
'01 cylinder head with con-caved spark plug seating-surface.
3) ECU
Can be identified by the model number [CI###] in white-letter on the upper right the body.
4) Carburetor
Can be identified by stamp indicated by white lines on the photo.
Can be identified by the model number [CI###] in white-letter on the upper right the body.
4) Carburetor
Can be identified by stamp indicated by white lines on the photo.
Features of settings by year
'97
Unleaded gasoline was introduced for the first time. Adjust ignition timing to avoid rich feeling in summer and detonation in winter (Retarding ignition timing is effective against detonation)
'98-'99
Pwj fitted carburetor was introduced for the first time.
The Pwj became effective in preventing detonation (Pwj designed to prevent detonation). (Pwj of smaller #40 or #42 were used)
'00
Like the 250, Pwj was used for carburetor settings. Larger Pwj#48 is cut after peak output power for smoother high revving (Pwj designed for setting)
'01
Increased low-to-middle torque oriented engine characteristics, effective for rising at the corner. Pwj #48 with MJH#3.9, rich setting designed not to lose powerful middle speed range.
For users who bought used machines and want to improve potential performance, it is recommended that parts be replaced with parts of latest year model for more potential.
Parts for '01 RS125R
Crankcase Crankshaft Cylinder Cylinder head ECU EX Chamber Carburetor Harness'
97 RS125R * - * * * * * *
'98 RS125R - - - * * * * -
'99 RS125R - - - * * * * -
'00 RS125R - - - * * * - -
* = Can be used if all the related parts are replaced
- = Same specifications (can be used even if different in part number)
'97
Unleaded gasoline was introduced for the first time. Adjust ignition timing to avoid rich feeling in summer and detonation in winter (Retarding ignition timing is effective against detonation)
'98-'99
Pwj fitted carburetor was introduced for the first time.
The Pwj became effective in preventing detonation (Pwj designed to prevent detonation). (Pwj of smaller #40 or #42 were used)
'00
Like the 250, Pwj was used for carburetor settings. Larger Pwj#48 is cut after peak output power for smoother high revving (Pwj designed for setting)
'01
Increased low-to-middle torque oriented engine characteristics, effective for rising at the corner. Pwj #48 with MJH#3.9, rich setting designed not to lose powerful middle speed range.
For users who bought used machines and want to improve potential performance, it is recommended that parts be replaced with parts of latest year model for more potential.
Parts for '01 RS125R
Crankcase Crankshaft Cylinder Cylinder head ECU EX Chamber Carburetor Harness'
97 RS125R * - * * * * * *
'98 RS125R - - - * * * * -
'99 RS125R - - - * * * * -
'00 RS125R - - - * * * - -
* = Can be used if all the related parts are replaced
- = Same specifications (can be used even if different in part number)
SP125 Limited
22 Walker Wood, Baildon, Shipley, West Yorkshire, BD17 5BE, England
Telephone 01274 583231 steve@sp125racing.com Mobile 07738 626165
22 Walker Wood, Baildon, Shipley, West Yorkshire, BD17 5BE, England
Telephone 01274 583231 steve@sp125racing.com Mobile 07738 626165
SP125 Limited Disclaimer
Honda, HRC and all other parts supplied by the SP125 Limited are not guaranteed when used in competition events.
As such, it is a condition of our making all parts available that it is solely the decision of each individual, rider, team member or
team whether they choose to use any part supplied and in doing so, absolve the manufacturer and SP125 Limited of any or all
such claims, including damage to equipment and/or injury to personnel irrespective of how caused.
All parts remain property of SP125 Limited until paid for in full.
All 'special order' parts, that are ordered specially under the instruction of the customer, are non returnable and non refundable.
Honda, HRC and all other parts supplied by the SP125 Limited are not guaranteed when used in competition events.
As such, it is a condition of our making all parts available that it is solely the decision of each individual, rider, team member or
team whether they choose to use any part supplied and in doing so, absolve the manufacturer and SP125 Limited of any or all
such claims, including damage to equipment and/or injury to personnel irrespective of how caused.
All parts remain property of SP125 Limited until paid for in full.
All 'special order' parts, that are ordered specially under the instruction of the customer, are non returnable and non refundable.
