Moreover as Marty was putting together the S3 rules he overlooked a little issue; Not all years of CR125 were the same - leading to what would become a "Frankenstien" of various years of parts to build the most powerful "Stock" motor.  Marty was working on resolving this when he was replaced at SKUSA.

Where SKUSA set a standard of leadership with all things shifter, over the last few years they began to stumble.  Even today the SKUSA S3 rules are more like a series of suggestions rather then specifications.  Recognizing the potential of Stock Moto and the need for a concise set of specifications that would keep development to a minimal cost, Kartweb Staff set out to develop the 125 Stock Shifter Standards.  These released as an open protocol document meaning no one had to stay "within the lines" and were free to use/change/ignore any of the specifications identified. 

2005 has been a very positive year for the growth of Stock Moto.  Between the various sources of CR125 retailers, they report a total of 78 motors sold in the first 10 months of the year.

For 2006 there are currently 6 variations of rules for Stock Moto that will be running in 9 Regional and 1 National Series.  Five of these rule sets are very similar as they all root from the 125 Stock Shifter Standards.

1. Kartweb 125 Stock Shifter Standards (KW)
2. Northern California Kart Club (NCK)
3. South West Regional Challenge (SWRC)
4. Woodbridge Kart Club (WKC)*
5. Florida Winter Tour (FWT)*
6. SKUSA

* = Rules still in draft

There are 7 basic elements to set specifications for;

1. Induction System
2. Exhaust System
3. Cylinder Head
4. Cylinder/Piston
5. Ignition
6. Crankcase
7. Clutch & Gears

The following identifies where each of the current promoters stand on these rules;

1) Induction System

1) Air Filters/Air Box deviations:

• SKUSA and SWRC do not allow Air Filter
• KW, NCK, WKC, FWT allow either to run

2) Fuel Pump

• KW, NCK, WKC, SKUSA in line with Standards
• SWRC and FWT have not specified

3) Carburetor

• KW, WKC, FWT in compliance
• SWRC not defined
• NCK, SKUSA restricted to Keihn brand

4) Carb Boot

This is one of the "hot spots" in the class.  The CR Boot does not allow larger seat on most chassis.  The RS boot does allow a larger seat to fit although there is a concern the RS Boot will provide more power.  The fact is the RS Boot has stuffers designed for the very different RS Reedcage resulting in a slight drop of power when used with the CR Reedcage.

• KW - allows RS Boot with stuffers removed
• NCK, WKC, FWT - allows RS Boot with stuffers intact
• SWRC, SKUSA - CR Boot only

5) Reeds and Reedcages

Reeds are nearly impossible to validate as "OEM".

• KW, WKC, FWT- Reeds are open, stops may be bent, cages untouched
• NCK - Reeds are open, stops may be bent, cages untouched
• SWRC not defined
• SKUSA - Reeds are open

2) Exhaust System

1) Pipe

Pipes are a major part of tuning a 2 stroke.  There are no ideal pipes commercially available that can be validated by a tech official from a set of dimensions.  NCK has managed to secure an RLV 6800 that is used for tech purposes and as such limits the class to one pipe.  This isn't feasible for everyone.  Pipes are a replacement item after 12-15 hours due to metal fatigue.  The ideal is to have a single pipe & silencer specified with hash marks at measurement points, and a silencer that can be readily verified for packing material.  These do not yet exist.

• KW - Pipe open but must not measure greater then 17-1/8" in circumference
• NCK - RLV 6800 only, and meets Tech Sample Pipe measurements
• WKC - Not yet defined
• FWT - RLV 6800, RCE T3, Leary, but must not measure greater then 17-1/8" in circumference
• SWRC - Open
• SKUSA - RLV 6800, RCE T3, Leary

2) Silencer

Silencers are a tuning element just as the pipe is.  Various packing materials such as different sizes of Steel Wool can alter the pressure building extending the power band at higher RPM.  Specifying a silencer without enforceable tech may be worse then leaving it open.

• KW - 10" x 2.5" diameter minimum, or within local noise ordinance
• NCK - 12-14.5" long with specific dimensions on the core.  Steel Wool or Fiberglass packing is allowed.
• WKC - Not defined yet
• FWT - Within local noise ordinance
• SWRC - Not defined
• SKUSA - 10" x 2.5" diameter minimum

3) Cylinder Head

SKUSA originally introduced this class with an 11.0 CCV rule.  Honda CR125's can range from 10.5 - 11.4 depending on stack up of tolerances.  As the head and cylinder are CNC controlled including ultimate Exhaust Port height, raising or lowering the cylinder to meet a CCV will not affect relative port timing.  However using CCV opens the possibility of reshaping the combustion chamber (narrower and tighter squish) which will produce more power.  The proposed solution is to use a profile gage and the tooling is currently in construction to be released in December.  This will eliminate the need for a CCV Rule.  It is expected that everyone except SKUSA will be using the profile gage and minimum deck height to control the CCV.

4) Cylinder - Piston- Bore

Cylinders are the major differences among the promoters.  The 99 model CR125 cylinder offers the best choice as the exhaust port heights are machined in the same operation as the deck and floor is machined.  They are among the most repeatable critical measurement areas of all the model years and even better, they have the lowest price.

The 2000/2001 cylinder offers superior performance over the 99 in the upper part of the power band, beyond the HP peak point.  They all have about the same peak,  To get the benefit of a 2000/2001 cylinder requires the 2000 crankcases as they are designed to match the port channels.  

SKUSA and SWRC are the only promoter who allows a range of years rather then limiting the cylinder and head to 99 only.  Southern California SKUSA competitors have been buying pro-built motors and as a result the number of later model cylinders/crankcases are proliferating and dominating. 

1) Cylinder

• KW, NCK, FWT, WKC - 99 only
• SKUSA, SWRC - 99-2002

2) Port Controls

• KW, NCK, FWT, WKC - dimensional limits and Port Map
• SKUSA, SWRC - not specified

3) Piston

• KW, FWT - open to same dimensional measurements as OEM
• NCK - OEM only with 3 exhaust rib lube holes allowed
• WKC - not defined yet
• SWRC - not specified
• SKUSA OEM only

 

5) Ignition

Different years of CR125 uses different CDI modules and stators.  Connectors are not interchangeable.  CDI modules are very difficult to tech without special electrical hardware and trained operators.

• KW, NCK, FWT, WKC - 99 only
• SKUSA, SWRC - 99 - 2002

6) Crankcase - Crankshaft

1) Model Years

• KW, NCK, WKC, FWT, SWRC - not specified
• SKUSA - 99-2002

2) Internal mods ("Legacy")

• KW, NCK - provisions allowed at a regional level only with 10 lb handicap
• FWT, WKC, SWRC not defined
• SKUSA - not allowed

3) Kick Start Boss Removal

• KW, NCK, WKC, SWRC - allowed
• SKUSA SWRC - not allowed

4) Main Bearings

• KW - Steel only, any class of fit
• NCK, FWT -  OEM only
• SWRC, WKA - not specified
• SKUSA not allowed

6) Clutch - Gearbox

All are in agreement that clutch needs to be OEM, gears to be OEM per 97 model ratios.  The only question here pertains to polished gears which provides no performance advantage nor can it be tech'd.