msa 50cc comer specification sheet - 158677/b &...

COMER C50 SPECIFICATION SHEET 2015 - 158677/B

NUMBER OF PAGES : 22 (twenty-two)

TECHNICAL CHARACTERISTICS

40MM

38MM

48CC

4% MIX

ELECTRONIC

SHORT THREAD

CENTRIFUGAL 3 PIECE

10 TOOTH 219 PITCH

DELL'ORTO SHA-14-12L

ALUMIUM/NIKASIL

COMER SPA

C50

REGISTERED MSA/COMER IMPORTER

Kyalami Grand Prix Circuit

1 Allendale Road

Midrand

Gauteng TEL : 011 466 3060 DATE:

MSA 50CC Comer specification Sheet

- 158677/B & 158677/A

ENGINE TYPE COMER C50

CYLINDER

BORE

STROKE

DISPLACEMENT

FUEL

IGNTION

MANUFACTURER

MODEL

MSA STAMP OF APPROVAL

SPARKPLUG

CLUTCH

PINION

CARBURETTOR

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height

width 10.3mm

20.3mm MAX

MAX internal

internal

25.3mm

MAX

external

128 deg Max

138 deg Max

Cylinder - Exhaust Port

Port Durations

Exhaust Port

A mixture of approximately 50/50 2-stoke oil/petrol will be used to check the combustion chamber volume

COMBUSTION CHAMBER VOLUME 6.7CC MINIMUM

measured on the vertical external sparkplug thread.

A 0.2mm thick feeler gauge that is 8mm wide must

be used to measure port durationsInlet Port

width8mm

gauge thickness0.2mm

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width

19.3mm

MAX

internal

21.2 mm height

MAX 8mm

external MAX

internal

128 deg Max

138 deg Max

Cylinder - Inlet Port

A mixture of approximately 50/50 2-stoke oil/petrol will be used to check the combustion chamber volume

Port DurationsA 0.2mm thick feeler gauge that is 8mm wide must be used to

measure port durations

Inlet Port

Exhaust Port

COMBUSTION CHAMBER VOLUME 6.7CC MINIMUM

measured on the vertical external sparkplug thread.

RE-NICASIL OF CYLINDERS IS NOT PERMITTED

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21.2mm

MAX

width

97.4 mm

MIN

no modification of any

ports permitted at all

Cylinder - Transfer Ports

20.4mm

Inner part of transfer

Port at base of cylinder

MAX

61.4mm

Removal or addition of material is

FORBIDDENMAX

20.7mm

MAX

Outer part of transfer

Port at base of cylinder

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45.9mm

MIN

67.2 mm Internal diameter

MIN

C3 or C4 8 ball steel cage bearing

only. Ceramic bearings are NOT

permitted

Removal or addition of material is

forbidden

Alternative makes of oil seals and bearings of the same type (single row deep metal cage) as original are

permitted.

No crankcase gasket permitted.

Inside cranckase width - bolted together minimum 39 mm +/- 0.3 mm

Crankshaft - Casings

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width

35.6 mm

+/- 0.2mm

87mm

+/- 0.1mm

19mm

+/- 0.2mm 68mm

+/- 0.1mm

31.5mm

+/- 0.5mm

ID of big end pin hole

Crankshaft

Machined surfaces Machine Marks

+/- 0.2mm

5.5mm

ALL MEASUREMENTS TAKEN FROM CENTRE OF CORRESPONDING POINT BELOW

MASS OF

CRANKSHAFT:

complete with piston,

rings, circlips and small

end pin MINIMUM 670

GRAMS

no

alteration/machining

of crankshaft keyway

groove permitted in

any form whatsoever.

Inside cranckase width - bolted together minimum 39 mm +/- 0.3 mm

measured opposite big end pin

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ring grooves:

height

1.52 mm

+/- 0.05mm

piston has 2 ring groves

height

28.3mm

MIN

height

38.6mm

MIN

overall height of piston

40.6mm

MIN

Piston

Note factory markings on piston crown

It is only permissable to machine the bottom skirt of the piston to the minimum heights as stated above. No

further machining or modifying of the piston in any other area is permitted.

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Piston Pin / Small End Pin

height

32.8mm

+/- 0.2mm

id

6mm

+/- 0.5mm

od

10mm

+/- 0.2mm

Piston Rings

height

1.47mm

+/- 0.02mm

Piston Pin and Rings

ONLY ORIGINAL PISTON AND RINGS MAY BE USED, TWO RINGS MUST BE FITTED TO THE PISTON AT

ALL TIMES

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Height

7mm

MAX

Width

5mm

MAX

Ignition Coil

Mounting : M4 screws used for attaching coil must have

thread from top to bottom and may NOT be machined

FJ 2007 Model only

ONLY TYPE FJ 2007 PERMITTED

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Coil Mountings on Casing

M4 holes only

NO welding or

repairing of these lugs

is permitted. If

damaged,the casing

MUST be replaced

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MASS: 378

grams

minimum -

measured

without

nuts, bolt

and

washers

Only surface were machining is allowed to

obtain the minimum weight

NOTE

casting

marks

FJ 2007 Model only

Flywheel

Keyway groove verified with a "no go guage" - thickness of 2.40mm.

keyway groove - max width 2.39mm

must have

"FJ"

CASTING

MARK

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The flywheel key may be removed completely. There is no further specification on the keyway if used.

Ignition timing may therefor be adjusted by rotation of the flywheel .

Flywheel Woodruff Key and Starter Cover

Flywheel Cover

Flywheel Woodruff Key

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Height

15 mm

MAX

ID

14.6 mm

MAX

Width

20mm

MAX

Inlet Manifold

ID of inlet hole

MAY be machined

to MAXIMUM size of

14.6 mm

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49.5 mm

MIN

ALL CLUTCH / PINION COMPONENTS MUST BE PRESENT AT ALL TIMES AS ORIGINALLY SUPPLIED

Clutch spring must have

8,5 coils

Clutch

ONLY ORIGINAL PARTS MAY BE USED, NO REBONDING OF CLUTCH PAD PERMITTED

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overall

height

9.7mm

+/- 0.1mm

Clutch Spring weight ( each)

5.6 grams minimum

5.9 grams maximum

Clutch Drum Pinion

86.6mm

MAX

mimimum mass - 113 grams

Clutch

Spring

thickness

2.0mm +/-

0.05mm

Clutch Drum ID

Clutch

Clutch Hub

Clutch Spring

no machining permitted

only original springs may be used

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MAX

MAX

The maximum internal diameter of the seat is 1.50mm. The emulsion tube must remain standard as

supplied and may not have an internal diameter greater than 1.80mm

The side bleed holes from the emulsion tube are subject to the following maximum dimensions:

Top 1.25mm: Bottom 0.80mm

Carburettor

Pinion - 10 tooth - 219 pitch

Please see notes at the end of this specification sheet for further carburettor information

ORIGINAL TYPE ONLY

diameter "A" = 1.26mm no godiameter "B" = 0.81mm no godiameter "C" = 0.81mm no go

SEAT HOLE SIZE = 1.5 mm Max

CARBURETTOR NOZZLE VERIFY WITH NO GO

GUAGE

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Only the following type of sparkplugs may be used

CHAMPION RCJ7Y

BOSCH WS5F

NGK BPMR7A

12.5mm

MAX

3mm

MAX

width height

25.7mm 13.2mm

MAX MAX

Bracket MAY be removed

Exhaust

Sparkplug

The baffle may either remain in place, as

it is supplied, or alternatively it must be

completely removed. No additional

modifcation of the baffle is permited if it

remains in place.

The standard type plug gasket must be used and no modification other than electrode gap settings

shall be allowed

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The standard factory fitted air cleaner and foam element may be removed and replaced with a standard

commercially available cone filter of the brand K&N or BMC (same form, and type as pictured

in this specification sheet). The filter element must be of the concertina (CONE) type with a thickness

of not less than 2mm. (as pictured below)

Airfilters

K&N TYPE

BMC TYPE

IT IS OPTIONAL TO REMOVE THE STANDARD TYPE AIRFILTER

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Carburretor Fixation Bracket

A bracket may be fitted to the inlet manifold mounting screw/s and attached to the carburetor as per or similar to the photos contained below in this specification sheet. This is to protect the carburetor from cracking or falling off. Screws may be fitted to the carburetor allowing for the attachment of the bracket. The holes for the screws being used to attach the bracket must be BLIND ended. A piece of foam may be fitted between the carburetor and bracket to absorb vibration

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MSA – 50cc COMER Specification Sheet 158677/A

Refer :- SECTION K – INDIVIDUAL SPECIFICATIONS OF THE KARTING HANDBOOK

24. CADET CLASS SPECIFICATIONSThese regulations are in addition to those stated under Section J 23 or others stated elsewhere in the Karting articles affecting this class.

MINIMUM MASS OF KARTWith Comer C50 engine: 73kg complete in racing trim including driver, helmet and all protective clothing.

A. CHASSIS

a) The chassis must comply with their respective MSA Specification Sheet. Numbered 158677/A and/or those available on the MSA website as well as per Art. 34F.of the official Motorsport South Africa karting regulations.b)All components must be the same make and type as supplied as original equipment by the MSA Karting Commission accredited dealer except for rear hubs, rims, sprockets and carriers, brakediscs, seats, seat stays, bearings and carriers (provided these are of the same type), steering wheel, rear bumpers assemblies and rear bumpers and protection as referred to in 23.12 c) of these regulations. Tubular side pod brackets of steel or aluminum, and with a maximum outside diameter of 20mm, may be used. Non-standard metal floor trays/pans of 2mm thickness (+/-0,5mm), may be used.c)The axle shaft must be a maximum of 25mm diameter solid or hollow magnetic material.Chrome plating of the axle is not permitted. The length of the axle can be reduced to a minimum of 745mm. The rear axle bearing hangers may be slotted for the purpose of aligning the axle. It is also permitted to slot the engine mounting plate on the chassis to accommodate the proper fitment and alignment of the engine to the chassis.d)The fitment of nonstandard or additional seat stays/supports is permitted.e)It is permitted to fit two caster/camber washers for camber or caster correction. No more than two washers may be fitted i.e. on/at the top and bottom of the stub axle assembly. It is also permitted to drill holes in the stub axle to accommodate the washers provided the diameter does not exceed 12mm.f)It is permissible to fit plastic or metal devices or attachments to protect or maintain the integrity of the sprocket and chain assembly from damage or dislodgement while on the circuit.

B.ENGINE

The only engine permitted is the Comer C50 equipped with recoil starter, centrifugal clutch, andDellorto SHA 14-12L carburetor, air cleaner and exhaust silencer. Unless specified or permitted elsewhere, the unit must be raced as supplied. The unit must comply with Specification Sheet reference MSA 50CC Comer specification Sheet - 158677/B & 158677/A perArt.34 G (i). Replacement parts must be affixed and orientated in the same way as supplied or stipulated by the original engine, equipment or component manufacturer. Any replacement part, or dimension of any part not specified on the Specification Sheet must be the same as the genuine part obtainable from the MSA Karting Commission accredited dealer for COMER C50 engines. All components must be standard as supplied by the original component manufacturer except as listed below:a)The repair of damaged threads by helicoil is permitted and damage to internal and external parts ispermitted and may be repaired by metal or epoxy fillers provided such repair are done without affecting the original internal dimension. No repair which has the effect of altering the original dimension of the engine, will be permitted, i.e. blueprinting under the guise of repairs will not be permitted.b)Studs, bolts, nuts, tie rods and washers may be replaced with non-standard parts of different dimension provided these are similar and perform the same function as the original.c)Alternative makes of oil seals and bearings of the same type (single row deep metal cage) as original are permitted.d)Non-standard gaskets may be used. It is permitted to add additional base gaskets for the purpose of achieving correct combustion chamber capacity.e)Mating surfaces may be lightly refaced to prevent leaks provided that not more than 0.10mm is removed and that any affected dimension stated on the spec sheet still conforms.f)The standard factory fitted air cleaner and foam element may be removed and replaced with a standard commercially available cone filter of the brand K&N or BMC (same form, and type as pictured in the specification sheet). The filter element must be of the concertina (CONE) type with a thickness of

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MSA – 50cc COMER Specification Sheet 158677/A Cont.

in the specification sheet). The filter element must be of the concertina (CONE) type with a thickness of

g) Metallic engine spacer plates may be fitted between the engine and chassis mounting plate topermit proper alignment between the engine and chassis. The combined maximum thickness of the plate or plates and any engine mount may not be more than 50mm. The engine may not be mounted more than 50mm above the chassis, measured from the top of the chassis to the mounting face of the engine. The Standard engine mounting plate welded to the chassis of the Topkart may be removed and replaced with a conventional type engine mount with under clamps.h) It is permissible to machine the standard detachable inlet manifold to the maximum internaldiameter as contained in this Specification Sheet.i) Stress fractures and other breakages of the external faces of the crankcase may be welded and machined to the original dimension and specification as per this Specification sheet. NO welding or repairing of the coil attachments lugs is permitted. If these are damaged, the casing MUST be replacedj)It is permissible to drill two holes, one in the barrel casing and the other in the crank half assembly for the purpose of fitting engine builder seals.k)Suitable cross-drilled bolts must be fitted to accommodate the sealing of engines.l)Only one fixed engine/axle ratio and chain type is permitted. Engine sprocket 10 teeth Axle sprocket 89 teeth Chain pitch 7.76 (type 219)m)Only standard type factory fitted black FJ 2007 ignition coils may be used for these engines.Alternative plug caps however, may be used. Retaining cap screw diameter may not be reduced from standard. The ignition fan used must comply to the one detail in teh specificarion sheet. The ignition keyway may be completely removed. If it is not completely removed it must remain in place and comply with the specifications contained i nthe specification sheet.n)The setting of the appropriate ignition coil gap remains open as long as all specifications contained in this specification sheet are adhered to.o)Only three types of spark plugs of the same type (extended nose) are permitted – Champion RCJ7Y /Bosch WS5F/ NGK BPMR7A. The standard type plug gasket must be used and no modification other than electrode gap settings shall be allowedp)Exhaust silencers shall be standard units as supplied by the original equipment manufacturer and must conform to the specification sheet for this class.q)The exhaust silencer may be cut open along the overlap seam to facilitate the removal or re-attachment of the exhaust baffle and thereafter completely welded or brazed so that it remains completely sealed. The baffle and plates must either be completel yremoved or remain un modified.No other openings or modifications are permitted other than those referred to in this specification sheet for this class. The exhaust attachment bracket may be removed and any residual opening welded closed again.r)The protective metal or plastic exhaust silencer heat shield may be removed and dispensed with.s)Only the Dellorto SHA14-12L carburetor may be used and must conform to the specification sheet for this class.t) The opening through which the fuel passes through, in the fuel tank tap may be bored out to facilitate the free flow of fuel through this opening. The original type fuel tap must be used.

C.TRANSMISSION

Only one fixed engine/axle ratio and chain type is permitted. Engine sprocket 10 teeth Axle sprocket 89 teeth .Chain pitch 7.76 (type 219)

D. IGNITION

a)Only standard type factory fitted black FJ 2007 ignition coils may be used for these engines.Alternative plug caps however, may be used. Ignition coil retaining cap screw diameter may not be reducedfrom standard.b)The setting of the appropriate ignition coil gap remains open.

c) The flywheel key may be removed completely. There is no further specification on the keyway if used. Ignition timing may therefor be adjusted by rotation of the flywheel .

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MSA – 50cc COMER Specification Sheet 158677/A Cont.

F.CARBURETOR

a)Only the Dellorto SHA14-12L carburetor may be used and must conform to the specificationsheet for this class.b)The choice of the main jet size is free.c)The maximum internal diameter of the seat is 1.50mm. The emulsion tube must remain standardas supplied and may not have an internal diameter greater than 1.80mm. The side bleed holes from the emulsion tube are subject to the following maximum dimensions: Top 1.25mm: Bottom 0.80mm.d)The carburetor gauze fuel filter quadrants may be cut open and removed. It is recommended to install an inline fuel filter should the gauze filter be removed or portions cut out.e)A bracket may be fitted to the inlet manifold mounting screw/s and attached to the carburetor as per or

similar to the photos contained in this specification sheet. This is to protect the carburetor from cracking or falling off. Screws may be fitted to the carburetor allowing for the attachment of the bracket. The holes for the screws being used to attach the bracket must be BLIND ended. A piece of foam may be fitted between the carburetor and bracket to absorb vibration

G.ELIGIBILITY REQUIREMENTS

a)The base gasket must be of a type and fitted in such a way that it will not become damaged upon removal and re-fitment of the cylinder during scrutineering/eligibility checks. In the event that damage does occur and, upon re-fitment of the cylinder using the damaged gasket, the combustion chamber volume is found to be less than the permitted minimum, the competitor will automatically be excluded.b)A mixture of approximately 50:50 2-stoke oil/petrol will be used to check the combustion chamber volume.

E.EXHAUST SILENCER (MUFFLER)

a)Exhaust silencers shall be standard units as supplied by the original equipment manufacturerand must conform to the specification sheet for this class.b)The exhaust silencer (new or old type) may be cut open along the overlap seam to facilitate the removal or re-attachment of the exhaust baffle and thereafter completely welded or brazed so that it remains completely sealed. No other openings are permitted other than thosereferred to in the specification sheet for this class. The exhaust attachment bracket may be removed and any residual opening welded closed again.c)The protective metal or plastic exhaust silencer heat shield may be removed and dispensed with.

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msa 50cc comer specification sheet - 158677/b &...

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