Championship Bike Regulations 2006
machines, except single cylinder machines, are based upon production
models, sold by manufacturers and their dealers in the UK for street
use. Proof of compliance rests with the competitor entering the
Single cylinder machines are exempt from production and street use
requirements. Single cylinder 2 stroke GP road race machines are not
allowed in this class. All machines must have unaltered VIN numbers.
NOTE: Ducati 748/749 Series machines are excluded from this class.
The organizers will appoint eligibility officers for the series. Their
decision on the
interpretation of the rules will be final.
1. Production machines not sold by manufacturers and their dealers for
street use in
UK via normal commercial channels may be approved on an individual
basis. The organisers will maintain a list of non-standard approved
2. All machines must comply with the machine preparation regulations as
set out in the 2006ACU Handbook for road race meetings.
Frame & Swinging Arm
Frame, cylinder head(s) and engine cases must be from the same
motorcycle. Single cylinder motorcycles may use any frame and engine.
The frame must be as originally supplied by the manufacturer of the
model. Strengthening gussets or tubes may be added. Only brackets or
supporting suspension, engine, or drive line components may be removed.
Swinging arms may be modified or replaced and rear shocks may be
replaced or relocated.
Single cylinder motorcycles are excluded from this restriction.
Reducing engine size of machines from stock displacement to meet Thunder
displacement limits is not allowed.
Liquid cooling is not allowed unless original equipment on the model
Original type of induction system must be retained. If a machine
originally was sold
with fuel injection, then it must remain fuel injected. If the machine
came with carburetors, then it must use carburetors, however they need
not be the
original type or size.
All drain plugs must be safety wired. External oil filter screws and
bolts that enter the oil or water cavities must be safety wired.
Engine displacement limits are absolute and are set as follows:
Single cylinder, Unlimited displacement
Twin cylinder, air cooled, Unlimited displacement
Twin cylinder, liquid cooled, 3 or less valves per cylinder, Unlimited
Twin cylinder, liquid cooled, 4 valve per cylinder, up to 750cc
Three cylinder, non-fuel injected, up to 1200cc
Four cylinder, air-cooled, up to 1200cc
Four cylinder, liquid cooled, 1990 to 1992 model year, up to 650cc
Four cylinder, liquid cooled (oil or water), pre-1990 model year, up to
All air-cooled, 2-valve, unlimited displacement
Thunderbike machines are required to meet a maximum power to weight
limit of 1 SAE horsepower for every 4.0lbs in weight (based on a
conversion of 1kg equal to 2.204lb), i.e. a maximum of 1hp per 1.814kg
Power to weight ratio will be calculated as the weight of the machine
divided by the tested horsepower when inspected. Inspections can occur
during post race or post qualifying inspections.
Any machine found to exceed the power to weight ratio on a dyno or
weighing device selected by the organizers may be excluded from the
Throttle stops or cable adjustments must be fixed or secured in a
manner that will prevent adjustment by the rider or crew without the use
of tools prior to dyno testing.
Switches or other operator controlled methods designed to affect
horsepower readings during dyno testing are strictly prohibited.
Machines are restricted to the mounting and use of one ignition or
engine management module during all competition. Adjustable modules or
modules with more than one setting must be mounted in such a way that
the settings cannot be altered by the rider or crew while on course or
prior to dyno testing.
Motorcycles must be fitted with a functional ignition kill switch or
button mounted on the handlebar that is capable of stopping the engine
Race numbers must be…………..on a …………………background and displayed on
the front of the fairing and on both sides of the seat unit. If no
fairing is fitted then a number board must be fitted to the front of the
machine capable of displaying the regulation size numbers.
The dyno operator or scrutineer may request removal of bodywork
before, during or after dyno testing, and may request removal of other
components for inspection.
Any machine not capable of post race dyno testing will be deemed to have
failed the dyno test.
Machines will be run on the dyno until, in the opinion of the dyno
operator, the maximum output is achieved. If, in the opinion of the
dyno operator or race official, an unsafe condition exists while
performing the dyno testing, the test will be stopped and the Race
Director or Chief Scrutineer will make the final decision on the dyno
All machines, or those selected by race officials, will run on the dyno
as soon as possible following the end of the race. Failure to report to
the dyno when requested will result in disqualification.