NEW 2012 RULES ANNOUNCED

THE NEW THUNDERBIKE AND THUNDERBIKE EXTREME 2012 RULES:

Overview :
Question : What sort of bike fits the BMCRC Thunderbike series ?
Answer : Most bikes built before the year 1999 and many newer bikes up to 2012.

The series is designed to allow engineers, riders, and anyone with an interest in improving
their bike more freedom from the current “production style” rules, prevalent in all forms of
current motor sport.

The rules give a wider range of bikes a chance at racing. You may take any machine eligible
and upgraded them (forks, brakes and suspension etc..)

The power to weight restrictions mean close racing is always achieved and any rider can be
competitive. Some competitors believe light weight is better, others that more power is best
and suffer the weight penalty. With winners on everything from Super mono singles to -
1000cc it looks like this argument is still yet to be resolved.

There are no restrictions on manufacturer for any parts other than the Frame/crank cases
combination.

Technically interesting - Exceptions that may be included :

A basic BMCRC Thunderbike must confirm to the rules shown, but any Technically interesting
machine whose engine conforms to the rules stated may also be considered and approved on
an individual basis by the series coordinator(s) and/or eligibility officer(s). Successful applicants
will be notified in writing by the series co-ordinator(s) and/or eligibility officer(s), their decision is
final.

If in doubt contact us at : mikedommett@hotmail.com.

Technically interesting could include but not restricted to : Spondon, Harris, Vyrus, Bimota, Rob
North, Self build or prototype or something interestingly modified. If in doubt and you want to
build something not obviously listed please ask. We actively encourage different ideas.

Please note the power to weight ratio applies to all machines.

All machines must have unaltered VIN Frame and Engine numbers.

All machines must comply with the machine preparation regulations
as set out in the current ACU Handbook for road race meetings.

If eligible, riders can choose between class 1 or 2 at every meeting. Choice to be made on entry.

BMCRC Thunderbike Classes :
Supermono : Single cylinder machine
Light weight : Machines up to 75bhp max
Sport : Machines up to 105bhp max
Extreme : Machines producing up to 130bhp max

Supermono, Light weight and Sport classes will run as the BMCRC Thunderbike group 1 Championship.

Extreme : will run on the same grid (separated) as the BMCRC Thunderbike group 2 championship.

The Rules & Technical specifications :
1. Race numbers and background colours:
1.1 Race numbers for this class must be Black on White background for Supermono, Light weight & Sport. Black on White background with Blue border for Extreme.

2. Chassis :
2.1 Frame, engine cases, and cylinder heads must be from the same production model and year where applicable.
2.2 Single cylinder motorcycles and accepted “technically interesting” motorcycles may use
any frame but the engine must conform within the engine (section 3) guidelines.
2.3 Anything other than frame, crankcases, and cylinder heads may be modified or changed subject to:
2.3.1 Seat sub frames where fixed may be replaced by bolt on replaceable rear sub frames.
2.4 Hybrid bikes (Big engine, small frame) whose engine conforms to the rules stated may also be
considered and approved on an individual basis by the series coordinator(s) and/or eligibility officer(s)
2.4.1 In the case of hybrid bikes, 4 stroke engines must be mounted in a 4 stroke chassis. 2 Stroke
engines mounted in a 2 Stroke chassis.
 

3. Wheels and tyres
3.1 Wheels may be replaced. Tyres can be treaded or slick. Rain tyres may be used.

4. Engine
4.1 Reducing engine size of machines from stock displacement to meet BMCRC Thunderbike class
displacement limits is not allowed.
4.2 Crankcases may be strengthened.
4.3 Cylinder heads may be modified but must retain the original number of valves.
4.4 Engine displacement limits are absolute and are set as follows:
Supermono/lightweight/sport classes
Single cylinder, Unlimited displacement. 2 stroke GP road race machines are not allowed in BMCRC Thunderbike.
Twin cylinder, air cooled, Unlimited displacement
Twin cylinder, liquid cooled, 3 or less valves per cylinder, Unlimited displacement
Twin cylinder, liquid cooled, 4 valve per cylinder, up to 750cc (Ducati 749 to 2004 model not S or R)
Three cylinder, non-fuel injected only up to 1200cc
Four cylinder air-cooled, 2 or 4 valve up to 1200cc.
Four cylinder, liquid cooled, up to and including 1996 model year, up to 650cc
Four cylinder, liquid cooled, up to and including 1994 model year, up to 850cc
(Model year refers to year of manufacture, proof of which lays with the competitor)
Extreme class.
Single cylinder Unlimited. 2 stroke GP road race machines are not allowed in BMCRC Thunderbike.
Twin cylinder air cooled Unlimited
Twin cylinder liquid cooled up to and including year 1999 model (includes 749 Ducati)
Three cylinder air cooled unlimited
Three cylinder Liquid cooled up to and including 1999 model.
Four cylinder Air cooled and liquid cooled max1000cc up to and including 1999 model.
(Model year refers to year of manufacture, proof of which lies with the competitor)

5. Electronic control systems
5.1 The use of electronic control systems to aid launch or traction are strictly forbidden.
5.2 Bikes are only permitted to have one loaded fuel map at any one time, and any bike found
with multiple maps loaded in the software will be excluded. Any ‘On-the-fly’ switch-able map is
strictly forbidden.
 

6. Power Restrictions (measured at the rear wheel)
6.1 Supermono : Single cylinder machine 1 SAE horsepower to every 1.56kg in weight.
(Eg current supermono 75hp weighing 117kg.)
6.2 Light weight : Machines producing up to 75bhp max 1 SAE horsepower to every 1.63kg in weight.
6.3 Sport : Machines producing up to 105bhp max 1 SAE horsepower for every 1.81kg in weight.
Extreme : Machines producing up to 130bhp max 1 SAE horsepower for every 1.46kg

6.4 Power to weight ratio will be calculated as the weight of the machine divided by the
tested horsepower when inspected. Inspections can occur post race or post qualifying or
randomly as required by the organiser or Technical Official
6.5 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 results.
6.6 All machines must carry a sticker identifying their power to weight class.
These will be :
........................Single Cylinder
........................Light weight
........................sports
........................Extreme
Stickers will be available from the race office at race weekends.

7. Controls
7.1 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.
7.2 Switches or other methods designed to affect horsepower readings during dyno testing are
strictly prohibited.
7.3 Machines are restricted to the mounting and use of one ignition or engine management
module during all competition. 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.
 

8. Technical Inspection
8.1 The dyno operator, Technical Official or person appointed by the race or series organisers to
ensure eligibility, may request removal of bodywork before, during or after dyno testing, and may
request removal of other components for inspection.
8.2 Any machine not capable of post race dyno testing will be deemed to have failed the dyno
test.
8.3 Machines will be run on the dyno until, in the opinion of the dyno operator, the maximum
output is achieved, 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 Clerk of the course
in conjunction with the Technical officer will make the final decision on the dyno test results.
8.4 Machines will be selected at random by race officials to run on the dyno as soon as possible
following the end of the race. Failure to report directly to the dyno when requested to do so
after the end of a race will result in automatic disqualification.
8.5 All machines must have at least 1 spark plug lead or coil lead accessible to the Dyno
operator to allow the pick up clip from the dyno to be attached. This ensures the quality of
the test and is in the competitors own interests. Machines where the lead is unavailable may
be disqualified.
8.6 All machines will be weighed on the BMCRC Technical Officials own scales. They will be
calibrated in house before each round and yearly as deemed necessary. They are definitive.
(Circuit scales will only be used if the BMCRC scales are unavailable).
8.7 Machine test procedure will be as follows.
Machine(s) will be selected.
The machine will be weighed with fuel but without rider.
The machine will be Dyno tested and a Pass or fail given. No other information will be
supplied.
8.8 Bikes which have been deemed to have failed the power to weight or technical rules may
be excluded from the race results. This exclusion may be for the entire meeting at the
discretion of the clerk of the course.

Motorcycles approved to race in BMCRC Thunderbike series providing they meet the power to
weight regulations. Please note this is not a definitive list but a guideline. Please ask if you
are unsure about the model you wish to race. There are some “exceptions” included which are
specific bikes thought to be in the sprit of BMCRC Thunderbike. They must still meet the Power to
weight regulations.

Group 1: Thunderbike Class 1

Group 2: Thunderbike Extreme

Aprilia
Shiver 750cc 1 or 2
550cc Twins 1 or 2
RSV1000R up to and including 1999 2
Falco up to and including 1999 2
RS250 1

Ducati
All Air cooled SS Range. 600cc – 1100cc 1 or 2
Multistrada 1 or 2
All air cooled Monster Range 1 or 2
748 1 or 2
748 with 853 Conversion 2
749 up to 2004 model not S or R 1 or 2
ST2 and ST3 1 or 2
916 Biposto & Strada (Special Inclusion) 1
996 up to 1999 2

Honda
All Air cooled machines 1 or 2
RC30 1 or 2
RC45 2
VFR 750F up to and including 1999 2
CBR600 up to and including 1998 (Special Inc.) 1 or 2
CBR600FX up to and including 1999 2
CBR Fireblade up to and including 1999 2
VTR1000 up to and including 1998 (not S model) (special inclusion). 1 or 2
NC30 1 or 2
RVF400 1
CB500 1 or 2
CBR1000F up to and including 1999 2
NSR 400 1
NSR 250 1

Kawasaki
All air cooled machines 1 or 2
ZXR-400 1
ZX-6R up to and including 1999 2
ZX-9R up to and including 1999 2
ZXR-750 1 or 2
ZX-7R up to and including 1999 2
GPZ 900 2
KR1-S 1
ER-6 Including Big Bigbore up to engine rules 1 or 2

Suzuki
All air cooled machines 1 or 2
GSXR 750 up to 1992 1 or 2
GSXR 750 up to and including 1999 2
GSXR 600 SRAD up to and including 1999 2
GSXR 400 1
GSX 600F 1 or 2
GSX 750F 1 or 2
TL1000S or R 2
RGV250 1
RG500/RG400 1 or 2
RF600 1 or 2
RF900 2
SV650 Including Big Bigbore up to engine rules 1
SFV Gladius Including Big Bigbore up to engine rules 1
GSF 750 1 or 2
Katana (Special Inclusion) 1

Triumph
All early air cooled triple models. 1 or 2
3 cylinder fuel injected models up to and including1999 2
T595 2
955i 2

Yamaha
All air cooled machines 1 or 2
TRX850 (Special inclusion) 1 or 2
FZR600 1 or 2
YZF-600 up to and including 1999 2
FZR-400 1
FZ750 1 or 2
RD500LC 1 or 2
FZR1000 up to and including 1999 2
YZF750 Inc SP Version 2
FJ1200 (special inclusion) 2
OWO1 1 or 2
R1 up to and including 1999 2
R6 up to and including 1999 2
RD350LC/YPVS 1
TZR250 inc 3MA & 3XV 1