It is the responsibility of the competitor to check his equipment (all components outside the engine seal as mentioned below), to assure that his equipment is conforming to the technical specification below.
DENSO A11.1 DENSO digital battery ignition, variable ignition Ignition timing, no adjustment necessary and possible.
System
A11.2 The casting of the ignition coil has to show the following in casting "129000-" and "DENSO"
(Image 1).
A11.3 Ignition coil must show 3 pins at the terminal (Image 2).
A11.4 Connector housing of ignition coil must have either black or green colour.
A11.5 The ignition coil has to be fixed by means of 2 original silent blocks to the gearbox cover. Only in case of chassis component interference with the original mounting location of the ignition coil, a supplementary extension bracket, rigidly constructed and fabricated of solid metal, of minimum dimensions and attached to the original case mounting holes, is permitted for mounting of the coil.
A11.6 Minimum length of ignition wire (high tension wire) is 210 mm from outlet of cable at ignition coil to outlet of cable at spark plug connector (the visible length of wire). Ignition coil must be in working condition (to be tested in case of doubt).
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO) 029600-0710, followed by a variable production code in the 2nd line (Image 3).
Battery must be fitted to the chassis with at least 2 screws. Position of the battery is free.
The earth strap may be fitted with a connector for ease of removal of the engine. Rotax Wiring Harness must be OEM only, with no fittings or repairs. The ignition coil can be relocated from the crankcase as far as the OEM harness will permit.
Centrifugal A13.1 Dry centrifugal clutch with engagement maximum
Clutch at 4,000 r.p.m.
This means that the kart must start to move before the engine speed reaches
4,000 r.p.m.
There are 2 versions of the steel clutch (Image 1) and both are legal to be used. The older version can be either untreated or nitrated configuration.
A13.2.1 Needle cage bearing 15x19x17 (Rotax part no.
632 415) must be fitted for 12, 13, 14 & 15 tooth sprockets. Plain bearing 15x17x20 (Rotax part no.
233 855) must be fitted for 11 tooth sprockets.
(Image 2)
A13.2.2 O-Ring 12x2.5 (Rotax part no. 950 815) must be fitted and must assure an appropriate sealing between the clutch drum and the needle/plain bearing.
A13.3 No extra lubrication or substance is allowed inside the clutch drum, in addition to the grease that originates from lubrication of the needle cage
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
AUSTRALIA - Version: 1 2 June 2015 Page: 10 of 36
A13.4.1 Steel clutch (both versions) and clutch drum must be within the following specifications:
A13.4.2 Height of clutch: Minimum = 11.45 mm
A13.4.3 Thickness of clutch: Minimum = 24.10 mm NOTE: Measurement has to be done at the 3 open ends of the clutch shoes, 5 – 10 mm from the machined groove (all clutch shoes must be completely closed at measurement, with no gap showing).
A13.4.4 Outer diameter of clutch drum:
Minimum diameter = 89.50 mm
NOTE: Diameter has to be measured with a sliding calliper, just beside the radius from the shoulder (not at the open end of the clutch drum).
A13.4.5 Inner diameter of clutch drum:
Maximum diameter = 84.90 mm
NOTE: The inner diameter has to be measured with a sliding calliper. The measurement has to be done in the middle of the clutch drum (in the contact area of the clutch drum).
A13.4.6 Height of sprocket with clutch drum assembly:
Minimum height = 33.90 mm
A13.4.7 The original Rotax clutch (3 spring) is eligible to be used at any event until further notice.
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
Intake silencer with integrated, washable air filter has to be used with all parts as shown in the illustration and has to be mounted on the support bracket with two screws (in dry and wet
condition).
Intake Silencer case bottom is marked on .the inside with the Rotax part no. “225 015”
Intake Silencer case top is marked on the inside with the Rotax part no. “225 025”.
Air filter must be installed as shown in illustration.
The original square type intake silencer is not eligible to be used for Rotax National Series, State Championships or events where Rotax is run as a standalone class. It can be used in Restricted TAG, TAG and Sportsman style classes.
Dellorto carburettor with “VHSB 34” cast in the housing of the carburettor.
“QD” or “QS” is stamped in the housing of the carburettor.
The complete inlet bore in the casting of the carburettor must show a cast surface.
Carburettor Slide shows digits “40” in casting Jet needle stamped with “K98” only.
Settings of the carburettor adjustment screws are free.
The following two combinations of floats and idle jets are legal:
Combination 1:
For carburettor insert 12.5 (as per illustration at rule 15.16.1) floats marked with “5.2gr” must be used. Idle Jet and Idle Jet Insert stamped with the digits “30” must be used.
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
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A15.8 All jets must be correctly seated and securely fitted.
A15.9 A minimum required size of Main Jet may be determined for each race event by a
“Supplementary Regulation”.
A15.10 Needle Valve assembly stamped with the digits
“150” (Image 1)
A15.11 Needle of Needle Valve marked with diamond symbol “INC” only (Image 2).
A15.12 Start Jet is stamped with the digits “60”.
A15.13.1 Needle Jet is stamped with “FN 266”.
A15.13.2 Total length of Needle Jet = 54.00 +/- 0.3 mm
A15.13.3 Length of bottom section of Needle Jet
= 11.50 +/- 0.2 mm
A15.13.4 Top bore diameter of Needle Jet
= 2.60 +/- 0.15 mm (measured 2mm inside)
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
A15.13.5 4 x 4 cross holes diameter of Needle Jet:
Plug gauge 0.90 mm may NOT enter one of the 16 cross holes of the Needle Jet.
NOTE: Use jet gauge set (Rotax part no. 281 920)
A15.14.1 Idle Jet 30 and Idle Jet Insert 30 must be used with carburettor insert stamped 12.5, as per illustration at rule A15.16.1.
A15.14.2 Plug gauge 0.40 mm may NOT enter the bore of the Idle Jet 30.
NOTE: Use jet gauge set (Rotax part no. 281 920)
A15.14.3 Plug gauge 0.40 mm may NOT enter the bore of the Idle Jet Insert 30.
NOTE: Use jet gauge set (Rotax part no. 281 920)
A15.14.4 Plug gauge 0.40 mm may NOT enter one of the 4 cross bores of the Idle Jet Insert 30.
NOTE: Use jet gauge set (Rotax part no. 281 920)
A15.15.1 Idle Jet 60 and Idle Jet Insert 60 must be used with carburettor insert stamped 8.5, as per A15.15.2 illustration at rule A15.16.1.
Plug gauge 0.65 mm may NOT enter the bore of the Idle Jet 60.
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
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A15.15.4 Plug gauge 0.65 mm may NOT enter one of the 4 cross bores of the Idle Jet Insert 60.
NOTE: Use jet gauge set (Rotax part no. 281 920)
A15.16.1 Carburettor insert must show stamping of either 8.5 or 12.5, as illustrated.
A15.16.2 Plug gauge 0.60 mm may NOT enter the angular bore of the 8.5 carburettor insert only.
NOTE: Use jet gauge set (Rotax part no. 281 920)
A15.16.3 Plug gauge 0.90 mm may NOT enter the vertical bore of the 8.5 carburettor insert only.
NOTE: Use jet gauge set (Rotax part no. 281 920).
A15.17.1 Remove atomizer from the carburettor body using the Venturi Tool Set (Rotax part no. 676 034).
Total length of atomizer = 23.75 +/- 0.45 mm
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
A15.17.2 Length of cylindrical part of atomizer
= 15.75 +/- 0.25 mm
A15.17.3 Dimension of cutaway of atomizer
= 6.00 +/- 0.15 mm
A15.17.4 Diameter of cross bore of atomizer
= 4.05 +/- 0.15 mm
A15.18 Optional carburettor plug screw marked “ROTAX”
(Rotax part no. 261 030) is legal to be used.
A15.19 The two vent fittings must be connected with the original 180mm air vent hose.
(Rotax part no. 260 260).
Fuel Pump A16.1 The original MIKUNI Fuel Pump (diaphragm type) must be used.
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
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A17.4
A17.5
A17.6
The removal of the thermostat from the cylinder head cover is accepted.
For versions 1, 2 and 3, tape can be applied around the radiator. Tape may not be removed from the radiator during operation on the track. All other means of air flow control through the radiator are prohibited, except for the plastic flap on version 3.For version 3, the removal of the original plastic flap is accepted.
Version 1
Cooling area: Height = 290 mm, Width = 133 mm Thickness of radiator = 32 mm
Version 2
Cooling area: Height = 290 mm, Width = 133 mm Thickness of radiator = 32 mm
Version 2 has two legal options to mount the radiator to the retaining plate (see illustration).
Version 3
Cooling area: Height = 290 mm, Width = 138 mm Thickness of radiator = 34 mm
The word “ROTAX” is stamped on the side of radiator.
Radiator Coolant
A18.1 A18.2
Glycol base or soluble oil coolants are prohibited.
Radiator coolant system must be fitted with a catch tank of minimum 100mL capacity to retain radiator coolant overflow, in accordance with Technical Rules Chapter1 Rule 9(h)(iii) 2
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
Exhaust A19.1 Must be as supplied by BRP-POWERTRAIN and System cannot be modified except for the replacement of
the silencer absorption material and the use of threaded fasteners in place of the original rivets for securing the silencer end cap.
A19.2 Just one piece of standard isolation mat is allowed to be used. Can only be replaced with genuine spare part (Rotax part no. 297 981).
A19.3.1 Additional to the standard isolation mat is a special steel isolation mat which is legal, but not mandatory. It is to be fitted underneath the standard isolation mat, 10-12 mm from the end of the tube, with both clamps mandatory.
A19.3.2 Steel isolation mat dimension = 165 mm +10 mm A19.3.3 Clamp (1) must be fitted at a distance of
18 +/- 2 mm from the end of the tube.
Clamp (2) must be fitted at the end area of the steel isolation mat.
A19.4 Exhaust pipe versions 1, 2 and 3 with after muffler as shown in illustrations are legal to be used.
A19.5.1 Version 1
Tuned pipe and silencer are one piece. The silencer is welded to the 180o elbow and the tuned pipe (Image 1).
A19.5.2 Diameter of hole of end cap Maximum = 21.0 mm
A19.5.3 Length of inlet cone = 592 mm +/- 5 mm
(measured on outside from beginning of exhaust pipe until beginning of cylindrical part).
A19.5.4 Length of end cone = 225 mm +/- 5 mm A19.5.5 Outside diameter of 180o bent tube
= 41 mm + 1.5mm / -1.0 mm
(measure at beginning and end of bend).
A19.6.1 Version 2
Tuned pipe and silencer are one piece. The silence is welded to the 180o elbow. Two springs
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)
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A19.6.5 Outside diameter of 180o bent tube
= 41 mm + 1.5mm / -1.0 mm
(measure at beginning and end of bend).
A19.7.1 Version 3
The tuned pipe with 180o elbow and silencer are two separate pieces. The silencer is fixed with two springs to the 180o elbow and two springs to the tuned pipe.
A19.7.2 The silencer can be rotated so that the 90o elbow outlet of the silencer is pointing either downward towards the asphalt (preferred for lowest noise emissions) or upward towards the back.
A19.8 For measuring the exhaust gas temperature, a weld on a socket on top of the exhaust, 50 mm from the ball joint is allowed.
A20.1 Exhaust sockets version 1 and 2 are legal to be used.
Version 1
Without gasket ring (Image 1)
Version 2
With gasket ring (Image 2)
Measurement (C) must be at least 15.5 mm
A20.2 The maximum use of exhaust springs to fix the exhaust to the cylinder is 4 springs.
TECHNICAL SPECIFICATIONS – JUNIOR (MICRO) – (A) FR 125 MAX (NON EVO) OR (B) FR 125 MAX (EVO)