Rule re-write.

[firko]

Enough of this extended forks bullshit..........Ted you're getting caught up in some vortex where you're stuck on travel increase by modifying stock forks. As someone who's built a lot of specials and know a lot more people who have done the same, not many, if anybody modifies forks for more travel...shit, I never even considered it an option until you started going off. Most builders fit bigger diameter/longer /more efficient forks, forks that come stock with extra travel, not fluck with forks that were inadequate in the first place. Frame changes are about improving geometry and have only a minimal influence on travel.  The mods are mostly about getting the bike to turn better, track more efficiently and basically handle better. You and I must have been on different cosmic planes in the late seventies it seems....I recall seeing modified bikes all over the place where I lived in the 75-78 period and it was almost the same here in NSW.

[Brian Watson]

Well Mark.....I won't go searching for an extra inch of travel in my HVA forks...I lived and raced right thru the middle of the suspension revolution..not many guys had the loot to put different forks in their bikes..but went searching for extra travel by putting kits in the forks.. mostly the Jap guys as I recall... Then there were the guys who bought new bikes each year that didn't need to mod their old bikes.....Leave the suspension limits as they are..it is about re-creating an era...95 % of the guys on the start line raced pretty well stock bikes...

[Tossa]

not only that Watto most of the guys were just damn well enjoying themselves

[supersenior 50]

Well the "other thread" has gone to the dungeon, this one has gone full circle and done to death, so hopefully time to settle down and get on with enjoying our sport.
Get those kosher bikes entered for the Post Classic Nats, it'll be all good. The Classics have had a run of great events, and it's the Post Classic's turn to shine.

[FourstrokeForever]

Well the "other thread" has gone to the dungeon, this one has gone full circle and done to death, so hopefully time to settle down and get on with enjoying our sport.
Get those kosher bikes entered for the Post Classic Nats, it'll be all good. The Classics have had a run of great events, and it's the Post Classic's turn to shine.

Touche' Col. I hope to be able to make it to the PC's. I'm sure it will be a success. You Queenslanders know a thing or two about promoting and running events.

[DJRacing]

Now that lots of people's brains have exploded, here's the same rules with annotations in blue. (The blue bits aren't part of the rules - they help people understand the changes).

16.11 MACHINE ELIGIBILITY
16.11.1 Eligible Machines
16.11.1.1    Only machines conforming to the requirements set out in chapter 16 will be accepted for competition.
16.11.1.2    The onus of proof of eligibility shall rest wholly upon the rider or entrant of the machine. Service and parts manual publication dates are not proof of eligibility.

16.15.7 Acceptable machines and components:
All Eras: (this saves repeating a whole lot of stuff for every category)
a) Major Components are: Frame, swing arm, forks, wheel hubs, triple clamps, engine cases, cylinder(s), and cylinder head(s). A machine's era will be defined by its newest major component. (defining the major components is important - it makes the difference between "do I need to use old tyres?" and "can I fit the forks off my 2005 Honda?")
b) Any major component that is visually similar and operationally indistinguishable from the original will be accepted regardless of the date of manufacture. (I am not happy with "similar" - the word "identical" is too strict for minor differences like casting changes, but "similar" is too vague. Open to input on that one!
This bit also replaces the need to specifically allow identical carry-over models)
ba) Any major component that is visually similar and operationally indistinguishable from aftermarket components available in the era, will be accepted regardless of the date of manufacture. (As above)
c) Any modifications to major components must be using principles and techniques that were available in the era the machine is entered in. (just stops loop-holing tactics)
d) Rear shock absorbers will be in the original position(s), using the original mounting points. (As well as avoiding repeating the same thing over and over again, this kills the "single-shock to twin-shock Evo" bike argument dead)
da) Folding footrests must be fitted.
(I killed "exhaust must follow original lines" because it achieves nothing.
I killed the "must meet the noise test" stuff because its already in 16c)


Pre 60 Solo. This class is intended to represent the formative era of motocross. (Weakly worded - needs input from the old hands).
16.15.7.1     The pre 60 class is for machines that closely represent those built up to (and including) 1959 models.
16.15.7.3    Front wheel travel will not exceed 178mm (7 inches) rear wheel travel will be limited to 102mm (4 inches) measured at the axle.
16.15.7.4    Plastic and fibreglass is not permitted.
16.15.7.6     Period carburettors or Amal Mk1 Concentric.
16.15.7.7         Reed valves are not permitted. (Kind of redundant, but added for clarity)

Pre 65 Solo. This class is intended to represent the first generation of purpose-built motocross bikes. (Again, weakly worded pre-amble - input please)
16.15.8.1    The pre 65 class is for machines that closely represent those that were built up to (and including) 1964 models.
16.15.8.3    Front wheel travel will not exceed 178mm (7 inches) rear wheel travel will be limited to 102mm (4 inches) measured at the axle.
16.15.8.6    Carburettors of any type pre 75 round slide may be used.
16.15.8.7         Reed valves are not permitted. (as for Pre-60)

Pre 70. This class is intended to represent the era where 4-stroke machines lost their dominance and 2-stroke machines became dominant. (Ditto)
16.15.9.1     The pre 70 class is for machines that closely represent those built up to (and including) 1969 models.
16.15.9.2     Front wheel travel will not exceed 178mm (7 inches) rear wheel travel will be limited to 102mm (4 inches) measured at the axle.
16.15.9.4     Carburettors; any type of pre 75 round slide may be used.
16.15.9.5     Reed valves are not permitted.
16.15.9.9    Yamaha XS1 and XS650 engines are eligible.
16.15.9.10    Acceptable follow on models:  AJS Stormer 250;  Greeves griffon models; Yamaha AT1, DT1, CT1, RT1 without reed valve induction. (tightening up the wording slightly)

Pre 75 Solo. This class is intended to represent the last of the short travel suspension era.
16.15.10.1    The pre 75 class is for machines that closely represent those built up to (and including) 1974 models.
16.15.10.2    Front wheel travel will not exceed 178mm (7 inches) rear wheel travel will be limited to 102mm (4 inches) measured at the axle.
16.15.10.4    Carburettors; any type of pre 75 round slide may be used.
16.15.10.5    XS1 and XS650 engines are eligible.
16.15.10.9    Acceptable follow on models pre 75:
    Honda CR125M1, XL250K1, XL350K1, MT250 (all) and MT125 (all)
    Yamaha YZ360B, DT250B,
    Suzuki TS400 (all).

Pre 78 Solo and Women's Pre-78. This class is intended to represent the transition era between the short travel Pre-75 machines and the long travel Evo machines.
16.15.11.1    The pre 78 class is for machines that closely represent those built up to (and including) 1977 models.
16.15.11.2    Front wheel travel will not exceed 229mm (9 inches) rear wheel travel will be limited to 229mm (9 inches) measured at the axle. (I want to change this to 10", but in the spirit of not changing the regs, I have resisted...)
16.15.11.4    Carburettors; any type of pre 78 round slide may be used.
16.15.11.8     Acceptable follow on models pre 78

    CZ 125 1978, CZ400 1978,
    Montesa VB, (ditched the "must comply with suspension limits bit" because the bike has to comply with 16.15.11.2 and 16.11.1.1)
    Yamaha TT500 1978 (is this correct?)


Evolution. This class is intended to represent the era of long suspension travel, before water-cooling, disc brakes and linkage rear suspension became dominant.
16.15.12.1    The Evo class is for machines that use drum brakes, air-cooling and non-linkage rear suspension, as was commonplace until 1981. It also allows for later machines up to (and including) 1985 models that retained this technology. (yes, 1985. Locking Evo into an era kills off the SexMax and any variation of it, without harming any of the 'real' Evo bikes. It still allows the later Evo Huskies, later CZs, and DT175s(!) )
e) Evolution class bikes must have  No linkage suspension, No disk brakes, and Air cooled motors.
16.15.12.4    Carburettors; period flat slide carburettors and any round slide carburettor may be used.
16.15.12.9    The handlebars must be equipped with a protection pad on the cross bar. Handlebars not fitted with a cross bar must be equipped with a protection pad located in the middle of the handlebars covering the handlebar clamps. (not sure if this is supposed to be on the older eras too? Just repeating what's in the current rules).
f) Front forks must be of the non-USD type, where the fork seal(s) move with the front axle. (stops Simmons USDs and 84 KTM USDs).
(I've written this using Dave Tanner's interpretation which was basically 'we don't care if it came from a linkage/water-cooled/disc braked bike, provided the end result has drums, air and no link'. I don't personally agree, but its the closest we've got to an answer to that long running question, so I used it).


Pre 85 Solo This class is intended to represent the era of the first generation of disc front brakes, water cooling, linkage rear suspension and exhaust power valves became commonplace.
16.15.13.1    The pre 85 class is for machines that closely represent those built up to (and including) 1984 models.
16.15.13.2     Carburettors; pre-85 flat slide carburettors and any round slide carburettor may be used.
16.15.13.7    The handlebars must be equipped with a protection pad on the cross bar. Handlebars not fitted with a cross bar must be equipped with a protection pad located in the middle of the handlebars covering the handlebar clamps.

Pre 90 Solo This class is intended to represent the era where rear disc brakes, upside down forks, and the second generation of exhaust power valves became common place. (by second generation PVs, I'm talking about the multi-element ones like KIPS and HPP, rather than YPVS and ATAC).
16.15.14.1    The pre 90 class is for machines that closely represent those built up to (and including) 1989 models.
16.15.14.2    Carburettors; period flat slide carburettors and any round slide carburettor may be used.
16.15.14.7    The handlebars must be equipped with a protection pad on the cross bar. Handlebars not fitted with a cross bar must be equipped with a protection pad located in the middle of the handlebars covering the handlebar clamps.

(I know sod-all about sliders and sidecars, and there doesn't seem to be much stress around them, so I assume the rules for those are pretty well right?)
16.16 SLIDERS
16.16.1 Slider Frames
16.16.1.1    The frame must:

    Have a conventional swing arm rear suspension with twin shock absorbers,
    Have a front wheel diameter of 23”,
    Have a rear wheel diameter of 19”,
    Have rear tyres with a maximum tread pattern depth of 8mm,
    Not be fitted with leading-link front forks.

16.16.2 Slider Solo Engines
16.16.2.1    The slider engine must:

    Be a single cylinder,
    When four stroke be 2- valve push rod operation,
    Have a single spark plug,
    Be vertical in the chassis,
    Be fitted with a round slide carburettor, or
    Be a period two stroke compatible with class entered.

16.16.3 Slider Gearbox: Classic Long Track
16.16.3.1    The gearbox must have at least two gears.
16.16.4 Slider Sidecar Frames
16.16.4.1    Conventional type frames as used prior to 31st December 1976 must be used.
16.16.5 Slider Sidecar Engines
16.16.5.1    Engines must have been manufactured before 31st December 1976.
16.17 SIDECARS
16.17.1 All Classes
16.17.1.1    Left -hand and right -hand sidecars may compete against each other in Classic Motocross.
16.17.2 Frames and Parts
16.17.2.1    For the Pre-1975 classes, all performance parts except frames must be manufactured before 31st December 1974 and must comply with the following:

        Wheel track measurement, taken between the longitudinal centres of the rear and sidecar wheels must be between 810mm and 1100mm,
        The minimum ground clearance must be 175mm unladen,
        The maximum lean of the motorcycle at saddle height mustbe 50mm,
        The dimensions of the sidecar baseboard in plain view, taken from a line drawn no further rearwards than the lowest point of the front down-tube to the forward most point of the sidecar wheel tyre and terminating no further rearwards than a line drawn at right angles to the machine from the rearmost point of the rear tyre, must be:
            At least 760mm long adjacent to the sidecar wheel,
            At least 300mm wide with at least 25mm radius to all corners.
        There must be no more than 50mm between baseboard and motorcycle and between baseboard and sidecar wheel. The baseboard must be arranged so as not to allow the passenger’s feet to be trapped,
        There must be no less than 4 sidecar attachment points,
        Stirrup fitting for the passenger’s feet are not permitted,
        Handholds:
            Must be finished with a loop of at least 100mm,
            Must not project beyond a line taken with the outer edge of the sidecar mudguard or bodywork,
            Adjacent to the nose section of the sidecar and less than 200mm from the track surface must be at an angle of at least 45° from the horizontal.
        The rear end of the rear wheel mudguard must terminate not more than 65° above a horizontal line drawn through the rear wheel axle and be valanced to baseboard level on the inside,
        The sidecar mudguard must cover at least 135° of the periphery of the wheel and be valanced to baseboard level on the inside,
        No machine may be fitted with scoop or paddle tyres,
        Suspension travel must not exceed:
            152mm (6”) 178mm (7”) measured at the front axle,
            102mm (4”) at the rear axle.
        Rear tyre width must not exceed 135mm (5.3”),
        Brakes:
            Front – single caliper, single disc may be fitted provided they were manufactured before 31st December 1974,
            Rear – rear disc brakes may be used provided they were fitted as standard equipment for that particular combination.

    Only round-slide carburettors manufactured within the relevant period may be used,
    Engine capacity must be up to 1300cc.

16.17.2.2    Pre-1985 is for sidecars constructed with motors manufactured before 31st December 1984.
16.17.2.3    A lanyard operated ignition cut-out switch, operating on the primary circuit, must be fitted to the following with a maximum length of one metre:
DISCIPLINE
   
MACHINE
Motocross    Sidecars
Dirt track    Sidecars
16.17.2.4    Pre-1968 will be for sidecars constructed from road going frames and all major components are those commercially available within the period.
16.17.2.5    The following table sets out the machines and components which eligibility scrutineers may use as a guide in determining eligibility. Entrants must prove eligibility of machines not listed below.
MAKE
   
MODEL(S)
Wasp    All up to and including RT2, RT8 and RT14
Hagon    All up to 31st December 1974
Yamaha    XS 650 all models
Honda    Any K series
Norton    All 750, 850 to Mk2 only
Westlake    All up to 850cc and 31st December 1974
Triumph    All up to T150
CCM    All BSA B50 based models

[supersenior 50]

Just to clarify, Womens Pre78 means any machine up to Pre78, not just 75, 76, 77 models.

[FourstrokeForever]

 CZ 125 1978, CZ400 1978,
    Montesa VB, (ditched the "must comply with suspension limits bit" because the bike has to comply with 16.15.11.2 and 16.11.1.1)
    Yamaha TT500 1978 (is this correct?)

I don't see any reason why the 1978 can't be listed as a follow on model. It is basically the same machine as was produced in 1977.

Pre 75 Solo. This class is intended to represent the last of the short travel suspension era.
16.15.10.1    The pre 75 class is for machines that closely represent those built up to (and including) 1974 models.
16.15.10.2    Front wheel travel will not exceed 178mm (7 inches) rear wheel travel will be limited to 102mm (4 inches) measured at the axle.
16.15.10.4    Carburettors; any type of pre 75 round slide may be used.
16.15.10.5    XS1 and XS650 engines are eligible.
16.15.10.9    Acceptable follow on models pre 75:
    Honda CR125M1, XL250K1, XL350K1, MT250 (all) and MT125 (all)
    Yamaha YZ360B, DT250B,
    Suzuki TS400 (all)

Just to clarify on the acceptable follow on models.....

When you state the CR250M1, are you referring to the 1975 Model? And with the XL250K1 and XL350K1, are you referring to the centre port engined XL's?

Sorry to be a pain in the rectal area, but do the bikes that were manufactured with slightly more than 4" rear suspension have to comply with rule 16.15.10.2?

Great job everybody.

[FourstrokeForever]

It's a pity that the focus of the thread turned to personal agenda and the original intent seemed to go out the window. I'm pissed with myself for allowing myself to get involved in the pre 78 suspension bullshit which helped the thread come to a premature siezeure. For that I apologise. When Nathan first posted what must have taken him ages to collate, I was excited and thought that this could finally be the thread where everyone could contribute for the betterment of the rulebook and the overall sport. I genuinely thought that the last five years of folks whingeing on here about the inadequacies in MoMs (often with good reason) would inspire a rush of contributions full of positive ideas to help make the rulebook more user friendly. It started off well but as happen to most serious threads, it turned into yet another soap box for personal agenda. Once again I probably contributed to that by adding opinion to my ideas which in retrospect was a stupid rookie mistake. I hope Nathan can get enough out of what's on here to do a rewrite on the rules. He and I rarely see eye to eye on anything but in this case I admire his having a go and hope that the thread can still contribute something positive to his project.

In the greater scheme of things Firko, there was no mud slinging or personal attacks, well at least in this thread. And I think on the whole, there has mostly been food for thought brandied about rather than excess argument about a certain era.
Nathan has done a great job and should be commended for his efforts by all and sundry. He has obviously taken "Nathan" out of the equation and given thought to what the majority of feedback received wanted and hoped for.

[Big Bird]

I have just stumbled across this thread after a period of a few weeks where I've spent little time here.  My fullest congratulations to Nathan for biting the bullet and giving the rules re-write a red hot go.  And more so for taking the time to annotate it and explain the intent.  I'll be sure to work through it all before I make any detail comment, but Nathan you have my full respect for having such vision, and acting on it to deliver such a comprehensive review. 

Cheers,

Geoff

[KTM47]

Just to clarify, Womens Pre78 means any machine up to Pre78, not just 75, 76, 77 models.

Col for the PCMXC supp-regs we wrote the Women's class as (up to Pre 90)  The same could be done for the Classic Champs.  Up to means it includes everything under Pre 90 etc.  It needs to be written as "up to" because if you use the correct wording for Pre 78 it is only open to 75, 76 and 77 model bikes.

My view is the wording for all classes should be similar to Pre 78 so the class/es are only open to the bikes from that era eg Pre 90 85 to 89 models, plus carry over models.

Kevin

[supersenior 50]

Way ahead of you Kev. Both 2012 and 2013 Womens Class was "up to and including Pre78 machines"
I only posted the clarification to add to Nathan's contribuition

[Rossvickicampbell]

quick one - when the YZ360B is classed as a follow on - that also applies to the 250B?

[KTM47]

This is one of the rules that needs updating in the MOMS.  The facts are if an official read the rules as written there are a lot of things that are generally accepted that could be knocked back.

But there is the section in the front that says .

THE PHILOSOPHY AND STRUCTURE OF THE GENERAL COMPETITION RULES

No set of Rules can anticipate every issue which may arise in the conduct of a sport, especially one with as wide a variety of disciplines and competing interests as exist in motorcycling. The philosophy of these Rules is that good sense, cooperation and a fair and reasonable interpretation of reasonable Rules should be more important than “Rule Book Racing”.

So using the above if the YZ360B is legal then the YZ250B probably should be also.

[firko]

quick one - when the YZ360B is classed as a follow on - that also applies to the 250B

Ross, the YZ250/360B isn't regarded as a flow on, being a designated '74 model it's considered a legitimate, legal pre 75 bike. To answer your question as a hypothetical though, whatever goes for the 250 goes for the 360.