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Engine Specs

Rain Forecast

Race convenor

Kim Coughey 021-245-5990

Track manager-

Barry Monds

Race secretary/Grid Marshall -

Roxy Hart

Lap Scorer

Boo Durbin


Flag Marshall


Chief Steward-

Mark Dodge

Chief Scrutineers

Mike Limmer

Craig Durbin

Water kart pilot /Track prep


Te Aroha Dirt Kart Club Engine Specs

Alcohol rules for Shifter & Open Class Kart Engines

Cover Note

These rules are in conjunction with all/any other rules laid down by the TADK Club and must

be read/used in conjunction with those rules.


Only the Shifter and Open Class karts driven by senior members may run alcohol fuel.

Before running alcohol fuels, drivers/operators of alcohol fuelled karts must have had

discussions with and received confirmation from TADK Club Technical and Scrutineering


Membership/Race Card

Must show that the kart entered is fuelled by Alcohol

Alcohol Fuel

Mixture is to be of at least 15% petrol and must have “colour” when viewed in clear container

in daylight.


Alcohol fuel to be presented to Scrutineer at time of scrutineering.

Fuel tank

1. Must be of suitable material and construction to safely contain alcohol fuel.

2. Must be securely fitted to kart so as not to move or fret in any way.

3. Fittings must show no visible signs of leaking and must not leak.

4. Cap must be able to be securely closed.

5. Tank must have vent to catch bottle/s.

Fuel Lines

1. Fuel lines must be of suitable material and construction to safely contain alcohol fuel.

2. All tube to fitting connections to be clipped, clamped or tied to prevent slippage.

3. Must be securely fitted and located away from exhaust.

4. Must not allow any fuel leakage.

Fuel test

1. A “flame test” may be used to verify that the burning of fuel creates a visible smoke.

2. The test is to be conducted only by Technical Officer and Scrutineers.


1. If the fuel test does not conclusively show visible smoke the driver must either add

more petrol or oil to produce smoke.

2. Failing that, the driver will be excluded from further participation in the race meet due

to safety infringement.

Yamaha KT100 Engine Rules

Cover Note

These rules are in conjunction with all/any other rules laid down by the TADK Club and must be

read/used in conjunction with those rules.


Single KT 100 Piston Port Engine only as manufactured by Yamaha with standard external

appearance (no left hand conversions) from carburettor inlet to barrel exhaust outlet. Piston port

engine must retain piston induction.

1. The use of painted or surface applied thermal barrier coatings on or in the engine/engine

components and on or in exhaust components is prohibited. The use of a fabric type

exhaust wrap is permitted from the head flange to the muffler connection (including the

spacer and flange on the muffler. Wrap must not be on the tapered section of the muffler.

2. The use of anti-friction coatings on or in the engine/engine components is prohibited.

3. External modifications, which do not in any way affect a performance gain, are legal

4. VHT paint may be applied externally to exhaust/muffler.

Legal Additions

Legal additions shall be limited to the following:

Air cleaner, chain guard, motor mount, direct drive gear, extension of carburettor jet needles,

carburettor return springs, third bearing and adaptor, temperature gauge and tachometer, fin

dampeners, fasteners, gaskets, joiners in spark plug leads, non-original spark leads, carburettor

diaphragm cover breather pipes, air cleaner mount, non original spark plug caps are allowable.

KT Ignition

The standard KT 100S (unmodified) ignition to be used.

Alternative ignition

The fitting of the following Modules as an alternative to the standard KT 100S ignition module is


1. Yamaha, Victa, Atom, Delta, Wei/Shieh, Sig, Nova, PRD, and TCI., permitted.

2. Ignition key is a non-tech item.

Crankshaft and Conrod

1. Crankshaft must be the original KT 100S with a maximum stroke of 46.20mm.

2. The connecting Rod must be original KT100S, KT100J. The KSI Replacement rod will no longer

be allowable.

Exhaust Header Pipe

This item is not restricted to the original Manufacturer but must not have extraneous attachments,

fins or water cooling etc.

1. Modifications to fit exhaust temperature gauge is permissible.

2. Flex/pipe location flange must be visibly in line with the end of the header.


The cylinder must be of original Yamaha KT 100S manufactured materials only unless otherwise


1. The cylinder is not to have any additional / removable inserts / passages / tubes or dividers

of any type.

2. Porting is allowable but must be only to the existing ports in their

3. original intended layout. No additional ports or plugging of any

4. ports. Threaded inserts are permissible to repair existing threads;

5. studs may be replaced with bolts in existing location, or may have thread inserts to repair

casting if thread has failed. Studs must be in original position.

Cylinder Head

Must be of original design with no additions (metallic or otherwise).

Minimum capacity of 11cc

Hemispherical combustion chamber, concentric with bore/spark plug.

Head Gasket

1. Must be of original cross section and material

2. Minimum thickness of 0.508mm (0.020” ).

Inlet Tract Length

Minimum inlet track length shall be 63mm measured from the outer carburettor adaptor face to the

piston wall. Phenolic spacer and alloy adaptor must be retained. Gaskets may be added to achieve

the minimum dimensions.

Phenolic Spacer:

To remain as moulded by Yamaha factory and conform to the diagram below. Drilling of the phenolic

spacer mounting holes is permitted. Sealing face may be re-faced.


Pistons approved are Strike, H Piston (this piston has a graphite coating), Yamaha, KSI, KSI Mk11,

JDP/Vertex, ARC (forged and cast).

Maximum piston diameter is 53.00mm.

Piston top and dimensions to conform to OEM shape and dimensions.


1. Must be standard Walbro WB Series.

2. No additional holes or machining is permitted

3. Butterfly and shaft must be as manufactured.

4. It is permissible to repair the inlet seat and throttle shaft bore in the Walbro carburettor.

5. It is permissible to enlarge only existing fuel/air holes, but they may not be deleted or


6. All air must pass through the carburettor venturi.

7. Measurement Code:

As cast maximum Venturi diameter 24.13mm.

As cast (area will extend from the front of the carburettor to the progression discharge jet which

must have all or portion of this jet in the cast area).

(iii) Maximum downstream diameter 25.7mm.

(iv) Butterfly shaft must be located at the bore centre.

(v) Minimum carburettor body length of 37.5mm.

Inlet Silencer

All Yamaha engines must run an air silencer box attached to the front of the carburettor.

Pressured Fuel Systems

1. Additional fuel pump or pressurised systems are forbidden.

2. Squeeze type pump between the fuel tank and carburettor is permitted.