sp125racing
Follow us at
  • sp125racing
  • Honda RS125
    • RS125 Genuine Honda HRC Parts
    • RS125 Engine Parts
    • VHM Piston Height Tool Guide
    • RS125 Chassis Parts
    • RS125 Honda Wheels Tyrewarmers Sprockets
    • RS125 Honda Crash Protectors
    • RS125 Honda Brembo Brakes
    • RS125 Honda Handlebars Levers & Footpegs
    • RS125 Honda Stands
    • RS125 Honda Quickshifters
    • Battle Shifter Fitting Instructions
    • RS125 Special Tools
    • RS125 Honda Fairings
    • RS125 Honda Seats
    • RS125 Honda Mudguards
    • HRC Datalogger & Detonation Counters
    • Detonation Detection System
    • Replacement for HRC Detonation Lead
    • RS125 16 Setting Ignition Curve Changer
    • RS125 Ignition Pulse Simulator
    • RS125 Throttle Position Sensor Checker
    • RS125 Gear Change Light
    • RS125 Powerjet Controller
    • RS125 Powervalve Controller Box
    • RS125 High Viz Temp Gauge
    • RS125 Ni-MH Battery Pack
    • RS125 Honda How To Order
  • HRC Setting Data & Maintenance Information
    • RS125R / RS250 Basic Concept of Power Jets
    • RS125 / RS250 Settings using Detonation Counters
    • RS125 / RS250 Settings according to seasonal conditions
    • RS125R / RS250R Functions of carburetor parts
    • RS250R Carburetor Settings
    • RS125R Parts Combination according to model years
    • RS250R Parts Combination according to model years
    • RS125R / RS250R Optimizing riding position
    • RS125R / RS250R Suspension Settings vol.1
    • RS250R Suspension Directionality
    • RS125R / RS250R Points of engine and frame assembly
    • RS125R / RS250R Notes on Engine Maintenance
    • RS125R / RS250R Notes on Frame Maintenance
    • RS125R / RS250R Conservation for engine power
    • RS125R / RS250R Running In / Warming Up / Position Adjustment
  • Honda RS250
    • RS250 Genuine Honda HRC Parts
    • RS250 Engine Parts
    • RS250 Chassis Parts
    • RS250 Handlebars, Levers & Footpegs
    • RS250 Brakes
    • RS250 Honda Stands
    • RS250 Honda Quickshifters
    • RS250 Bodywork
    • RS250 Bike Specification 2008
    • RS250 16 Setting Ignition Curve Changer
    • RS250 Ignition Pulse Simulator
    • RS250 Honda How To Order
  • Honda NSF250R
    • NSF250R Genuine Honda HRC Parts
    • NSF250R Engine Parts
    • NSF250R Honda Wheels Tyrewarmers Sprockets
    • NSF250R Honda Handlebars Levers & Footpegs
    • NSF250R Chassis Parts
    • NSF250R Honda Crash Protectors
    • NSF250R Honda Stands
    • NSF250R Honda Quickshifter
    • NSF250R Bodywork & Airbox Parts
    • NSF250R Honda How To Order
    • NSF250R High Viz Temp Gauge
  • Nova Gearbox - KTM Moto3
  • Terms and Conditions
  • Steve Patrickson Profile
  • Race Team Archives
    • 2023 sp125racing Team
    • 2022 sp125racing Team
    • 2021 sp125racing Team
    • 2020 sp125racing Team
    • 2019 sp125racing Team
    • 2018 sp125racing Team
    • 2017 sp125racing Team
    • 2016 sp125racing Team
    • 2015 sp125racing Team
    • 2014 sp125racing Team
    • 2013 sp125racing Team
    • 2012 sp125racing Team
    • 2011 sp125racing Team
    • 2010 sp125racing Team
    • 2009 sp125racing Team
    • 2008 sp125racing Team
    • 2007 sp125racing Team
    • 2006 sp125racing Team
    • 2005 sp125racing Team
    • 2004 sp125racing Team
    • 2003 sp125racing Team
    • 2002 sp125racing Team
    • Tom Carne Profile
    • Jordan Weaving Profile
    • Rob Guiver Profile
    • Brad Ray Profile
    • Chrissy Rouse Profile
    • Matt Davies Profile
    • Ben Barrett Profile
    • Matthew Hoyle Profile
    • Lee Costello Profile
    • Nicole McAleer Profile
    • Connor Behan Profile
    • Luke Hinton Profile
    • Jordan Malton Profile
    • Dan Moreton Profile
    • Michael Smith Profile
    • Luke Jones Profile
    • Jamie Ashby Profile
    • Mark Clayton Profile
    • Joel Marklund Profile
    • Elliot Lodge Profile
    • Elliot Lodge 2018 Profile
    • Elliot Lodge 2019 Profile
    • Harvey Claridge 2018 Profile
    • Harvey Claridge 2019 Profile
    • Franco Bourne 2019 Profile
    • Calum Beach 2019 Profile
    • Jeremy Knight 2019 Profile
    • Cameron Horsman 2019 Profile
  • Contact
  • 2022 Race Dates
  • 2023 Race Dates
  • 2024 Race Dates

HRC Setting Data & Maintenance Information


RS125R / RS250R Notes on Engine Maintenance


Please  'Refresh' this page every time you visit.         If it is slow to reload, you know then that this page has been updated since your last visit.

Picture
Picture
 The RS provides the high potential for circuit use. Lack of the basic maintenance, however, will result largely degraded performance. Servicing should be regularly performed and parts be periodically replaced, if needed.

Periodic replacement parts
Item
Plug cap
Standard Cylinder
Standard Piston
Piston ring
Piston pin
Piston pin clip
Connecting rod small end bearing
Crankshaft

Counter Balance Bearing
Clutch outer
Spark plug
Ignition coil
Reed valve

Intervals
Every 1000km (cleaning for each maintenance)
Every 2000km
Every 500km
Every 500km
Every 500km
Every 300km (Every time clip is removed)
Every 500km
Every 2000km

Every 2000km
Every 2000km




Criteria

Wear or damage
Damaged skirt or wear
Partial loss of identification point, wear
Burning, damage, stepped wear

Burning, wear, damage
Deformation, damage
Deformation, damage
Wear, damage
Wear
Wear, damage
Loose, damage
Overhaul
Item
Front/rear suspension
Cables (throttle or clutch)
Brake master cylinder
Steering stem
Suspension link section
Wheel bearing

Interval
Every 2000 km or every 4 races

Every 2 to 3 races (every time races are done in a rainy day)
Every season

Every season (check needed after falling down)
At new vehicle, every time parts replaced
Abnormal noise, play, defective operation
Checking other fasteners
Check the brake system, front section, or rear axle section for loose fasteners. Also check wire lock. 



Reasons for specifying intervals in terms of kilometres for periodic replacement parts
Example: Pistons for which replacement is specified at every 500km



Durability: Reduced streaks on piston surface (oil bank)
                 Occurrence of cracks
Degraded performance: Deformed pistons
                                       Blow up (ring grooves struck by rings, wear) 


As described above, intervals in km are the ranges within which an appropriate racer can provide its inherent high performance or which will not cause durability related failure. (Likewise, these intervals have been specified for other parts. See owners manual)
Picture
Cylinder 
With increased power, the 2001 model year RS125R and RS250R have cylinder bore shape and timing similar to the manufacturer's kit engine.
Accordingly, cylinder maintenance has become more important than before.
Basically, it is recommended that the items described in the manual be followed. In particular, mentioned below is the description on the necessity for chamfering.

Picture
The chamfer on the upper surface of the exhaust port may be glittering when obliquely viewed from the skirt side of the cylinder taken from engines which have travelled to some degree.

Picture
The figure above shows a magnified view of the cross section of the port chamfer. The piston ring slightly protrudes into the exhaust port when the piston goes up and down.
This chamfer again rests in the bore surface. If there is, however, an angular (even obtuse-angle) section at the cylinder chamfer interface section, the piston ring movement gradually becomes bad, resulting in strengthened contact by the ring on chamfers.
For this reason, chamfer should be made. When chamfering is made for upper and lower ports, wet abrasive papers will be applied to the interface of the bore surface and the port chamfer at small angles (10 to 15 degrees) to make the interface round. 
Chamfer maintenance would avoid stuck rings or peeled plate at the cylinder port.

Picture
Piston
•Piston contact
Piston contact should not usually be removed. Severe contact with the cylinder is attributed to some other reasons. Pistons have special profile (out of round), which is designed to produce heat emission, providing proper contact when pistons and cylinders are subject to deformation.
Accordingly, careless piston modifications in profile will degrade the ideal profile, resulting in more contact with other portions.
Picture
Ring sticking 
With the increase of service engine speeds year after year, even if keystone rings are used, sticking may result.
If rings and pistons are new, ring groove modifications are not required against sticking. However, if stuck rings are found at the time of maintenance, the modifications must be done. Stuck rings may cause engine troubles as well as a significant power drop.
Stuck rings can be identified by signs of a failure exhibited at the engine start, such as unwillingness to start engines or abnormal engine noise emitted from the silencer. 
Picture
Piston rings 
The abutment of piston rings should be chamfered at the gap using a round file. This is intended to prevent stopper pins from being cut by rotational force generated when pistons are moving up and down.
Picture
Piston sizes (applicable until the year 2002 RS250R) 
Cross reference of piston and cylinder combination
Picture
*Cylinders for the 2001 year and later models bear no A/B identification markings. Instead, they have NXA stamped at the side. 


Handling cylinders and cylinder heads 
Extreme care should be exercised during handling cylinders or cylinder heads.
In particular, flawed mating faces may deteriorate adherence, causing blow by.
If there are projections caused by flaw or dent, they should be removed using abrasive paper to make the surface flat.
However, if flaws are present across O-rings or flaws are present in the O-ring grooves, appropriate cylinders or cylinder heads should not be used since O-rings cause blow by. 



RC valve (applicable until 2002 year RS250R) 
For the RS250R, unadjusted RC valves will result in significant power drop (1 to 5 PS). Even if piston maintenance is not performed, RC valves, once heated, should be readjusted since the valves displace. 


Clutch outer section 
The clutch outer section should be periodically serviced and replaced if necessary. If excessive plays or cracks are found during servicing, defective parts should be replaced as soon as possible. (clutch outer fasteners)
(Protruded fasteners may damage pulsar plates for the RS125R or casing cover for the RS250R.) 



Water seal 
When water pump seals are replaced to fix coolant leak from water pump, water pump shaft should be visually checked. If the shaft exhibits colour change or rough surface, just seal replacement will not solve the problem. In this case, both seals and shafts should be replaced. If coolant leak is again found after replacement of both parts, water pump bearing and balancershaft bearing should be replaced as well. 


Carburetor 
When cleaning carburetors, do not apply high pressure air to carburetors with floats installed. High pressure air would cause oil level in carburetors to get out of order, resulting in significantly wrong settings. 


Carburetor float
Carburetor float section is a very delicate part. Extreme care should be exercised during disassembly.
If oil level should go wrong, see owners' manual for proper adjustment. Wrong oil level would cause rich or lean mixture, or hesitation. Also, check that floats are smoothly going up and down. 
If floats do not move smoothly, rich feeling or hesitation may result when beginning to open the throttle. Also, unstable fuel mixture would cause frequent detonation.
Picture
Float level should be checked at the point at which float valve comes into slight contact with float lip.
Oil level height should be measured at the highest point of the float, instead of at the point of main jet.

Picture
2001 year model cylinder head
Secondary volume for the 2001 and later models is less than that for 2000 and earlier modelled by 0.2cc in cylinder head volume. The 2001 year model has a cylinder head with the centre protruded, making impossible the measurement of the volume when the head assembled (because of creation of air puddle). Single head only allows measurement. Secondary volume criteria


 Item     Volume when assembled     Single head volume

'00        11.6cc                               11.1cc
'01        11.4cc                               10.9cc


Non-standard combination will result in unwillingness to rev highly and vibration, leading to deteriorated potential performance.
The 2000 year model exhaust joint is different in joint diameter from the 2001 year model, making impossible its common use.


Picture
Exhaust joint
The 2001 year model has exhaust joint length and colour which are opposed to the 2000 year model.

 Machine          #1 front side                      #2 rear side

'00model          34.2mm black                    29.2mm silver white
'01model          27.5mm silver white            29.5mm black


Non-standard combination will result in unwillingness to rev highly and vibration, leading to deteriorated potential performance.
The 2000 year model exhaust joint is different in joint diameter from the 2001 year model, making impossible its common use.


Exhaust joint gasket
 The 2001 year model has a thin stainless gasket in comparison with its former thick copper gasket (for improved durability). Accordingly, like installation of exhaust joints to chambers, liquid gasket should be applied before exhaust joints are installed. 



Reed valve 
The 2001 year and later model has undergone changes to a reed valve body, having altered angle as compared with 2000 year model (2001 model has steep angles). 
Making reed valves thinner allows easy opening, and installation of supports secures functioning of valves when wide-open.
As described in the manual, valves, supporter and stoppers should be so installed to ensure their position
.

return to hrc setting information

return to honda rs125
home
SP125 Limited
22 Walker Wood,  Baildon,  Shipley,  West Yorkshire,  BD17 5BE,  England
Telephone 01274 583231      [email protected]      Mobile 07738 626165
Picture
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.
Powered by Create your own unique website with customizable templates.