Rule changes for 2021 are in progress. If you have suggestions, please email them to or reach out to us via the Contact Us form. A provisional 2021 rulebook is published here, and is embedded below. The rest of the rules on this page have not been updated yet.


The most significant PROPOSED, PROVISIONAL changes are:

  • Renaming of two classes: Supersport 125 to Supersport, and Superbike to Formula Middleweight.

  • New class: Street 125, for street-legal minis with minimal modifications such as Groms, Z125 Pros, Kymco K-Pipe 125, Benelli TNT 135, etc. Please read the details on this class if you're interested!

  • Simplification of tech rules. Silicone "goop" requirements have been eliminated except in one case because they didn't work. Bark busters are now required for all motorcycles with standard bars other than Street 125 motorcycles. Rules on peg sliders have been clarified.

  • Increase the maximum water-cooled two-stroke displacement to 100cc for powervalve motors and 105cc for non-powervalve motors. This allows KX100s in the class, along with 105cc CR85/pre-2019 YZ85 overbores and 100cc RM85s/post-2019 YZ 85s. The KTM 105 SX is intentionally excluded here. The intent is to make two-strokes more competitive against the CR150Rs.

  • Increase the maximum water-cooled two-stroke displacement in Formula Middleweight from 70cc to 72cc to allow for the most common KX65 big bore kit size to be legal.

  • Clarification of penalties for sprint and endurance races.

  • Changes to endurance championship scoring for better balance.

  • A rewrite of the sprint racing rules to remove the GP race and make the day simpler.

  • A re-structuring of the sprint and endurance sections of the manual to improve clarity.

  • Updating the transponder requirements to reflect changing requirements.

NorthWest Mini Moto Rulebook 2021 PROVISIONAL v1.pdf

Follow this link to the 2020 rulebook for Cascadia Mini Moto and Endurance Challenge.


This rulebook was last updated July 30, 2020.

If you have feedback on the rulebook, please contact us via email or join the discussion on our Facebook page.

The remainder of this page is a summary of rules, not the rulebook, and will not be considered authoritative if it conflicts with the rulebook linked above.


Bike Prep - ENDURANCE and GP

See the rule book for full details. This page is not authoratative, it is just a summary. In short:

Motorcycles must be in a safe, ready-to-race condition as determined by the technical inspector. All controls must be operational, including the kill switch, and there may not be any leaks, cracks, missing parts, etc.

No glycol-based coolant of any kind. Water and Water Wetter or other approved surfactants only.

Rounded, filled bar ends (plastic is OK) or bark busters are required. Axle sliders and bark busters are required for Open class motard-style motorcycles. Peg sliders are required for all motard-type motorcycles.

Transponders will be required; they will be either available for purchase at the track for a nominal fee or rented and reserved as part of the pre-registration process.

The following must be safety wired:

    • Oil drain bolts and oil filter cover bolts (filter bolts may use a silicone dab).

    • Oil fill plugs. R-clips are permitted.

    • External oil filters (using a hose clamp around the filter wired to a hard point).

    • Brake pad retaining pins must be secured with an R-clip or safety wire if not screwed in; they may be secured with a screw cap or dab of silicone if they are a screw-in type.

Other parts must be removed, secured with safety wire, silicone, or clamps - see Section 4.2 in the rule book for details. Among other parts, kickstands, license plates, and turn signals must be removed.

Catch cans are required for fuel and crankcase vent lines, but not for coolant.

BIKE PREP - Practice & Sprints

For practice days and the sprint/outlaw races, we have relaxed the technical requirements to make bike preparation easier.

Motorcycles must be in a safe, ready-to-ride condition as determined by the technical inspector. Chains must be tight, all controls must be operational (including the kill switch) and there may not be any leaks, cracks, missing essential parts, etc.

Tires must be in good condition.

No glycol-based coolant of any kind. Water and Water Wetter or other non-glycol coolants only.

Rounded bar ends (plastic is OK) or bark busters are required. Axle sliders and bark busters are required for motard-style motorcycles over 150cc. Peg sliders are required for all motard-type motorcycles.

The following must be secured with a silicone dab (or safety wired):

  • Oil drain plug

  • Oil filter

  • Oil fill caps

  • Axle bolts

All lights and reflectors must be completely taped over.

A fuel & crankcase catch can is required for sprint races but not for practice.

For sprint racing and to get timing during practice, RFID transponder tags will be required; they can be purchased during registration. A LIMITED number of tags will be available for purchase at the track.

Sprint/GP Racing

Sprint/GP championship cancelled for 2020 due to COVID-19 - single-event races will be held in August at MAC Track and TCKC in October.

Sprint/GP events will consist of at least one practice session for all divisions, one or more heat races for each division, one GP qualifying session for all divisions, one or more 15-lap moto races (depending on time and entries) for each division, and one 45 minute flag-to-flag GP race for each division. Winners in each class will be the highest-scoring rider in that class for the day. Times and race counts may be adjusted for schedule, and the GP race may be canceled for safety or schedule reasons without nullifying the day’s results.

Sprint/GP races will be divided into two divisions, lightweight (Supersport 125, Formula 125, and Scooter) and heavyweight (Superbike and Open). Riders may enter one race in each division. Additional "outlaw" classes may be added at each round if there is interest, see the event-specific Sign Up page for details.

Endurance Races and Teams

Endurance Challenge races will be 6-8 hours long and scored in a separate championship from Sprint/GP races. Endurance Challenge races are team events, and are run with a hot pit that allows racing stops for fuel, rider changes, and repairs.

Teams may consist of any number of riders. Riders must have appropriate gear for an asphalt race - race leathers or MX gear with full armor underneath. Textile riding suits are also acceptable. Please see Section 7.3 of the rulebook for complete information on rider safety equipment.

Riders and teams register and pay separately, and riders may ride on multiple teams. Teams must register online prior to race day - race day registrations for teams will not be allowed. Riders for each team may register the day of the race online before coming to registration.

Teams will need to conduct pit stops during the race for refueling. Pit stops have special rules and require at least two people and a fire extinguisher. All riders must read and understand pit stop rules in the race rulebook. Teams will be flagged and/or docked points for unsafe pit procedures.


Junior riders (under age 16) are permitted on endurance teams per Section 2.6. There is no Junior-specific category.

Junior riders will be given a separate class to ride in for moto/GP races depending on their age and experience. Junior riders who do not meet the skill requirements to ride the full GP race safely will be restricted to the moto races. Junior riders will be scored together, and will be given a championship if more than 5 riders enter for the year. Open class motorcycles are prohibited in the Junior class.

Common restrictions & definitions


All volumetric references below are to engine displacement. Displacement-based class rules apply to actual displacement, not original displacement, unless otherwise stated.

A GP frame is defined as any motorcycle frame that was originally sold with clip-on bars for use on closed-circuit road courses.

A Sportbike frame is defined as any motorcycle frame that was originally sold for street use, with DOT or equivalent equipment.

A Motard frame is defined as any motorcycle frame that was originally sold with knobby tires, one-piece handlebars, and was intended for off-pavement use.

A Scooter is defined as any machine with a step-through frame configuration and wheels 12” in diameter or smaller.

“OEM” is defined as the same shape, size, and materials as the part as listed by the manufacturer in the most recent parts catalog for that motorcycle. It includes OEM-equivalent aftermarket parts.

“Unmodified” is defined as no dimensional or material changes relative to OEM. Parts may be painted, cleaned, and polished, but the material, shape, size, and function of the parts may not differ from OEM.

“Stock-appearing” is defined as appearing to be the same shape and size externally as stock, but the part may be modified internally to improve performance. Functional external features of the part (such as cooling fins, exhaust pipe diameter, etc) must be unmodified.

“As delivered” is defined as how the motorcycle was available from the manufacturer.

Restrictions for all classes

  • Only single-cylinder internal combustion engines are permitted by rule. Electric motorcycles and multi-cylinder motorcycles will be evaluated and classed on a case-by-case basis.

  • Only commercially-available gasoline-based fuels are permitted. Ethanol blends up to E85 are permitted. Leaded fuels are permitted.

  • Nitromethane and methanol fuels are prohibited.

  • Forced induction is prohibited.

  • External chemical power enhancement (nitrous, etc.) is prohibited.

Class structure

The NorthWest Mini Moto classes are:

    • Supersport 125

    • Formula 125

    • Scooter

    • Superbike

    • Open

Supersport 125

Low-power, low-cost air-cooled motorcycles 125cc and under with a minimal number of changes.

All motorcycles:

◦ Unless explicitly stated otherwise below, components must remain unmodified. Modifications for performance are expressly forbidden unless listed below.

◦ The following internal engine modifications are permitted:

▪ Aftermarket oil pump and oil passage drilling/cleanup

▪ Heavy-duty cam chain

▪ Heavy-duty clutch springs and plates. Basket must remain OEM.

◦ Rear shock may be aftermarket but new price cannot exceed the average cost of a new OEM shock, set at $250 USD for 2020. Aftermarket springs are permitted.

◦ Front forks/suspension must be stock appearing.

◦ Airbox/intake modifications are permitted, including pod/foam filters.

◦ Modifications to controls, bodywork, tires, hoses, and cables are permitted.

◦ Removal of any part is permitted, unless required for safety.

◦ Brake shoes and all fluids may be replaced with aftermarket.

• Over 200lbs as delivered:

◦ May replace the exhaust with an aftermarket exhaust.

89cc or more, under 200lbs as delivered:

◦ Drum brakes only.

◦ Must use at least one OEM wheel size (diameter and width), and all OEM hubs. One wheel may be re-laced to a different rim diameter but must maintain the same rim width as the OEM wheel it replaces.

◦ Must have a stock-appearing exhaust and stock-appearing carburetor.

◦ Forks must be stock-appearing.

◦ Must have an unmodified head, including valves and camshaft, but excluding valve cover. The valve cover may be aftermarket.

◦ Must have a stock-appearing cylinder. Cylinder bore may be increased to displacement limits. If the cylinder is otherwise stock appearing but has an oil line outlet, that outlet may be plumbed to the valve cover. Oil coolers are explicitly prohibited.

◦ May use an aftermarket piston to change cylinder compression.

88cc or less:

◦ May replace both wheels with aftermarket 10” or 12” wheels of any width.

◦ May use disc brakes and modified or aftermarket forks.

◦ May use an aftermarket swingarm and shock(s).

◦ Unlimited modifications to the cylinder, top end, and exhaust.

Displacement limits:

◦ 4-stroke air cooled 2 valves: 125cc

◦ 4-stroke air cooled 4 valves: 100cc

◦ 2-stroke air cooled: 60cc

Formula 125

Formula class for smaller-displacement minis with open chassis and engine modifications.

• Unlimited engine and chassis modifications except as noted.

• Engine displacement limits:

◦ 4-stroke air-cooled: 125cc

◦ 4-stroke water cooled: 75cc

◦ 2-stroke air-cooled: 70cc

◦ 2-stroke water cooled: 50cc


All scooters that meet the displacement and power limits. Scooters may also race in regular motorcycle classes if they meet the requirements for those classes.

“Maxi” scooters, defined as scooters weighing over 275lbs, are prohibited from competition.

Three types of scooters, with different displacement limits, are recognized as legal in the Scooter class, each of which has different displacement limits and chassis or engine restrictions:

• Vintage air-cooled two-stroke:

◦ 225cc maximum displacement

◦ Stock-appearing engine cases

◦ Frame design must have been first sold prior to 1965. This includes Vespa smallframes, Vespa largeframes and Lambretta Series 1-4.

• Modern air-cooled two-stroke:

◦ 125cc maximum displacement

• Four stroke (any):

◦ 190cc maximum displacement

Restrictions for all scooters:

• Must use wheels 12” or smaller in diameter.

• Must use engine cases that match the original model frame – no motorcycle engine swaps.

• Cylinders and heads must be based on OEM scooter cylinders and heads – no motorcycle cylinder/head swaps.

• Frame must have been originally sold for street use; no bespoke racing frames.

Except for the restrictions as mentioned above, chassis and engine modifications are open.

Exceptions may be made on a case-by-case basis, as long as vehicle horsepower does not exceed 25HP as certified by team testimony, dyno evidence, or at-track comparisons. Contact race direction staff before the event to confirm machine legality.


Class for medium-displacement minis with open chassis and engine modifications.

• Unlimited chassis and engine modifications except as noted.

• Engine displacement limits:

◦ 2 stroke air cooled: 100cc

◦ 2 stroke water cooled

▪ Sportbike frame: 75cc

▪ GP or motard frame: 70cc

◦ 4-stroke 4-valve air cooled: 160cc

◦ 4-stroke 2-valve air cooled: 175cc

◦ 4 stroke water cooled: 125cc

◦ Displacement limits may be waived on a case-by-case basis for scooters and older machines. Contact race officials before race day to discuss exceptions.


• Unlimited chassis and engine modifications except as noted.

• Engine displacement limits:

◦ 4-stroke 2-valve air- or air-oil cooled: 250cc

◦ 4-stroke 4-valve air- or air-oil cooled: 212cc

◦ 4-stroke water-cooled: 150cc

◦ 2-stroke air-cooled: 125cc

◦ 2-stroke water-cooled: 95cc

◦ Displacement limits may be extended on a case-by-case basis if power at the rear wheel does not exceed 25HP as certified by team testimony and dyno evidence. Exceptions will be revoked or penalized if unfair advantage is evident during the race. Contact race officials before race day to discuss any exceptions.

Any addition of classes will depend on rider turnout and interest. If you’d like to add a class, please email NorthWest Mini Moto and let us know. NorthWest Mini Moto requires a minimum of 3 teams (for endurance) or 5 individual riders (for GP) be entered to race in any new class, and new classes must be added before the first event of the year.

If any class has fewer than two entrants at the first race of the year, it may be combined with another class and/or removed from the championship at the discretion of the race organization.

Example machines for each class (not comprehensive) are:

Supersport 125: Honda XR100 with a 120cc kit and an XR80 front wheel, Yamaha TTR-125 small wheel, Yamaha YSR50, Honda XR50 with an 88cc kit and front forks with disc brakes, stock Honda Grom, stock Kawasaki Z125 Pro

Formula 125: Yamaha TTR-125 big wheel (disc brakes), Honda NSR50, Honda NSF100, Piranha SSR 125, Ohvale 110, Aprilia RS50, Kayo MR125

• Scooters: Vespa smallframe, Vespa largeframe, Lambretta series 1-4, Honda Elite, Yamaha BWS

Superbike: KX65, KTM 65 SX, Honda CRF150F, Chinese YX-engined pitbikes with a 150cc-170cc 2-valve motor (SSR, Pirhana, etc), Ohvale 160, Kawasaki KLX-140, Vespa 100cc 2T scooter, Aprilia RS50 with a 75cc overbore

• Open: Honda CRF150R, CR/YZ/KX/KTM 85, Ohvale 190, Daytona 190cc motors (up to 212cc), Honda CRF230, Yamaha XT250