Australian Karting Association Inc. Technical Committee

Transcription

1 Australian Karting Association Inc Technical Committee Venue: Date: Time: 9am Page 1 of 22

2 2006 AKA Technical Committee Participants List John McCleverty Gary Light David Bertram Trevor White Harold Arnett John Whitfield Geoff Hall Ken Seeber Paul Riggs Chairperson NKC Representative Queensland New South Wales Victoria* Tasmania South Australia Western Australia Northern Territory Legend: *= Substitute delegate. (Apology from Kevin McKinnon VKA delegate, unable to attend due to family obligations) Page 2 of 22

3 Item 1 (AKATAS Item 2) Rule (a) Does not include the wording moulded in one piece. Tasmania feel this should be included to be consistent with Rule and 14.01(a) Not recommended, the helmet complies with the standard rule Item 2 (AKAWA Item 8) Rule Reword to include the previously amended requirement for the sealing nut to NOT have a through hole. To prevent possibility of allowing screwdriver access to remove nut by unscrewing stud. Admin Tidy up passed last year to be included in 2007 Manual. Issue addressed by 2006 Addendum No.7 Item 3 (AKASA Item 10) Rule 19.34(i) A competitor is permitted to use only one set of prescribed dry tyres AND only one set of prescribed wet weather tyres in any class, at any event. These tyres must be used from the start of the first qualifying session / heat 1 for the entire duration of the meeting, including all subsequent practice/carby sessions. This statement, or something similar, needs to be included into the manual to eliminate the arguments from drivers and crews at larger meetings. Re-word to Rule 19.34(i) A competitor is permitted to use only one set of prescribed dry tyres AND only one set of prescribed wet weather tyres in any class, including all practice from the commencement of the event/competition. Page 3 of 22

4 Item 4 (AKAWA Item 9) Rule Specify how many damaged or worn out tyres can be used. Probable understanding is one, but needs to be clarified. A karter could possibly have 4 new tyres fitted. No Action required. Item 5 (AKASA Item 8) Rule The microphone is to be located 4 metres (+/- 0.1m) above the centre of the track and to be aimed at the centre line of the track. This regulation is most impracticable at almost all circuits in Australia, because, to my knowledge, nobody has yet been able to invent a skyhook. The noise metre should be for measuring noise that we as human beings are exposed to, not the birds flying through the air. None of us are 4 metres tall and stand in the middle of the track during races. We are up to 2 metres tall and stand a minimum of 14 metres from the centre of a track during racing. If we are going to be serious and control the amount of noise produced by a kart, then let s at least formulate a realistic regulation to adhere to. Except for Formula 100 class (that very rarely runs anyway), all of our classes use a controlled muffler that has been designed to reduce noise emissions. Even at V8 Supercar events across the country, the noise measurers stand at track level with a hand held noise measuring device pointed towards the track. Sounds like common sense to me. Even our current rules on noise control contradict each other. Rule : From 1 st January, 2003 the permitted noise emission level from a kart must not exceed 98dBA when measured at a point 4 metres away with AKA vertical method. Rule : At normal tracks the permitted noise levels must not exceed 100dBA when measured at a point 4 metres above the centre of the track. No Action required. Page 4 of 22

5 Item 6 (AKAWA Item 10) Rule 25.01(e) Change rear axle to be of magnetic material to rear axle to be of steel. To clarify the intent of the rule, which wasn t to have axles made from magnets. Re-word to Rule 25.01(e) Rear axle to be of a ferrous material. Item 7 (AKAWA Item 11) Rule (b) Add this to state that the flex or spacer to have a maximum outside diameter of 45 mm. To prevent someone coming up with some dodgy tuning device in place of the flex. Re-word to Rule (b) The exhaust header pipe and muffler can be joined by a pipe or flexible tube with a constant wall thickness and constant diameter, ends must be within 5 degrees of perpandicular to the centreline of the tube, min 34mm ID max 45mm OD these being an absolute size all TOLERANCES included. (Amendments to class chapters required) Item 8 (AKAWA Item 12) Rule Reword to read Starting/ignition batteries, when fitted, must be securely attached to the kart. Batteries can be very securely and satisfactorily mounted at the rear of the seat, not just the frame. Re-word to Rule Starting/ignition batteries where fitted must be attached to the frame or seat. In a securely mounted (min 4 by 6mm ht bolts or two 6mm U bolts including saddles) four (4) sided (min height 10mm) box or bracket, the battery must be contained in the bracket by (1) two (2) 6mm bolts with a suitable top bracket, (2) minimum 15mm wide strap and "d" buckle, (3) minimum two (2) 7.5mm wide by 2mm thick uv rated "zip ties", (4) min 50mm wide "Velcro strap, Straps and Zip ties are not to pass over any sharp edges or under the Kart frame. The only type of batteries that can be used onboard a kart are Dry Cell, Gell type or Valve regulated sealed lead acid batteries. Page 5 of 22

6 Item 9 (AKAWA Item 13) Rule (new rule) New rule to specify that ceramic ball bearings cannot be used in engine or axle and wheel bearing applications. These bearings are comparatively very expensive over regular ball bearings, so eliminating them will remove any potential expensive must have perception. New Rule The use of ceramic bearings is not permitted. Item 10 (AKAWA Item 14) Rule Include a modification to the Piston Travel system to include a further check on the transfer port height. This would be done using a 5 mm pin that is inserted into the engine cylinder through the exhaust port. Would require the piston travel rod to have an extra groove. Note that as there are some current issues stemming from the exhaust/transfer split, it is suggested that should an engine be detected with the PTG test, then this would trigger a closer engine inspection of the ports. This has previously been discussed between some of the Tech Committee. To be able to detect (in the field ) for engines that might have had the transfer ports illegally raised, but without the complication of having to remove the cylinder. Design and measurement to be provided by Ken Seeber and Kevin McKinnon for presentation to 2006 AGM for introduction in Item 11 (AKAWA Item 15) Rule (new rule) Include a procedure for measuring the AKA39 exhaust. As this is the only muffler allowed in Clubman, it is quite possible that this will be subject to people looking to improve it. For the same reasons that we have a procedure for the AKA14. Page 6 of 22

7 Amendment to Rule Procedure for use of AKA14 and AKA39 gauge The AKA14 test rod has cut outs for ease of compliance checking. At all points of checking, the plane across the inlet pipe must fall within the cut outs on the rod for the respective measurement. Step 1 Insert rod into the inlet of the muffler, pass through the 19mm outlet tube until the rod contacts end cap of baffle. Nominal measurement 570mm AKA14 Nominal measurement 470mm AKA39 Dimension B Step 2 Withdraw rod until lip locates on exhaust outlet tube (end of 19mm tube) Nominal measurement 512mm Dimension C Step 3 Withdraw rod until lip locates on main deflector plate Nominal measurement 422 Dimension D Item 12 (AKAWA Item 16) Rule (d) (new rule) New rule to read 50W Yamaha J rod not eligible. To apply this Clubman rule to the hybrid Formula Australia engine. Proposed amendment to rule Connecting Rod: Can be either of the following and must be stock: (a) Yamaha or KSI. (b) Minimum/Maximum rod length, centre to centre 99.87mm mm. (c) Conrod alignment may be either top or bottom. (d) Bearings and spacers are non-tech items (e) 50W Yamaha J rod not eligible. Page 7 of 22

8 Item 13 (AKAQ Item 17) Rules and A minimum weight be struck for J & S crankshafts. Ease of checking for illegal lighting of components. Withdrawn, unworkable. Item 14 (AKAQ Item 14) Rule Crankcase Second paragraph to read it is permissible to use ARC electric start crankcase, crankshaft and ignition on Yamaha KT100S if clutch and starter motor is fitted. Tidying up of the rule. Amendment to Rule Crankcase: The crankcase ports will remain as cast. The minimum chordal distance measured with a vernier caliper across the widest section of the transfer ports shall be 97.5mm minimum. (Refer diagram below). Main bearing bores can be repaired with the use of metallic inserts. It is permissible to use ARC electric start crankcase, crankshaft, on Yamaha KT100S if clutch, starter motor battery and electrical system is fitted. NOTE: Existing crankcases that are narrow may be spaced with a thicker gasket mm YAMAHA KT 100S DIAGRAM IS FOR DIAMENSIONAL REFERENCE ONLY DIAGRAM IS FOR DIMENSIONAL REFERENCE ONLY Page 8 of 22

9 Item 15 (AKAQ Item 15) Rule Crankcase Allow ARC electric start crankcase complete with crank/rod/electrics on KT100S if clutch and starter motor are fitted and operational. With the move towards clutches all measures to accommodate the simplest form should be adopted. Included in Item 14. Item 16 (AKAQ Item 18) Rules and A minimum weight be struck for J & S flywheels. Ease of checking for illegal lighting of components. Withdrawn unworkable. Item 17 (AKAQ Item 16) Rule Ignition Put a maximum internal diameter measurement to the flywheel/rotor of 61.8mm. To prevent any modifications internally to the flywheel/rotor. Maximum inside diameter measurement to the flywheel/rotor to be 62.00mm (Add measurement to drawing Page 208) Item 18 (AKAWA Item 17) Rule Chapter 40 Rule Chapter 41 Introduce wording to have restrictor plates measured and sealed before racing. This is the 3 rd time this has been put up. To eliminate any post race grief. Amend to Rule & Restrictor plates to be measured and sealed before competition for State Championships and approved major competitions. Page 9 of 22

10 Item 19 (AKAWA Item 18) Rule Review the restrictor plate size of Ø13.02 To achieve closer parity between the Comer and the restricted KT100J engine, where the current situation is that the Comer has a definite advantage. Testing to be carried out to get parity between SW80, S80, ARC M1 and Yamaha J. Item 20 (AKANSW Item 4) Rule 51.08/1 Tyres and Hubs Rule Changes of Tyres Unless otherwise stated in these rules (i) A competitor is only permitted to use one set of prescribed dry tyres and only one set of prescribed wet weather tyres in any class, at any event. Teka wish to amend Rule / 1 To include The number of sets of prescribed dry tyre and prescribed wet weather tyre allowable in an event will be specified in the supplementary regulation. Due to the varying durations of Endurance races just one set of tyres may not be sufficient. Amend Rule Kart Specifications and Regulations 1. Tyres and Hubs Permitted tyres are as follows: Dry - Dunlop SL1 (Front: 10 x 4.50 x 5 Rear: 11 x 7.10 x 5) Wet - Maxxis WT3KTM (Front: 10 x 4.50 x 5 Rear: 11 x 6.00 x 5) or - Dunlop KT6-SLW1 (Front: 10 x 4.00 x 5 Rear: 11 x 6.50 x 5) Tyres may be marked by the Scrutineer(s) prior to qualifying. The number of sets of prescribed dry tyre and prescribed wet weather tyres allowable in an event will be specified in the supplementary regulations. Page 10 of 22

11 I tem 21 (AKANSW Item 9) Change to allow ballast systems for Endurance Karting TEKA Presentation Teka ballast system presentation to be presented by TEKA at the Committee Conference. To allow a quick and easy change of weight ballast during competition as this is not required in other classes. Held over Item 22 (AKANSW Item 8) Disabled Driver Criteria Criteria for disabled drivers be as follows: 1. Engineers Certificates 2. Final inspection by State Technical Officer 3. Photos and or drawings of hand controller signed by driver 4. AKA registration of hand controller to driver by number or photo I.D. per year As driver renews licence he/she is also up for additional costs, at present by having the same hand controller re inspected for engineering certificate on renewal every year. This way if we register the hand controller to the driver having photo I.D. each year signed and dated on reverse will alleviate the additional costs so at anytime the controller can be I.D. at race meetings for conformity. Referred back to AKANSW Executive. Page 11 of 22

12 Item 23 (AKASA Item 13) Engine Specifications Engine specifications need to all be published in the one place. Engine measuring is a joke when those responsible cannot do their job for fear of litigation or the Stewards will not follow through with a charge for an illegally modified part because its technical specification was not commonly known. Suggestion would be to create a separate Technical Manual in addition to the AKA Manual in which the specifications of all engines, tyres and other components are listed. This would make a single record book that is possible to be on-sold, and if it is an official in print AKA publication makes its contents a lot less questionable. Currently the Comer and Junior Max specs are in the AKA manual - why have they alone been singled out?? These could be removed from the current manual and included in this new book along with all other engines like Leopard, Rotax Max, ReSa, KT100S and KT100J. To be addressed by technical specifications re-write. Item 24 (AKASA Item 14) The current homologation papers/specs of the KT100SD and KT100SEC need to be made a matter of official record, the AKA currently only holds the homologation papers for the early style KT100SE - that are dated 1979!! To be addressed by technical specifications re-write. Page 12 of 22

13 Industry Submissions ARC Submissions: Documents attached A1 Homologation application Approved in principle, the Tech Committee recommend the NKC approve on track testing to confirm dyno tests and parity testing of M1 and R1. ARC M1 Midget (TAG) Homologation application ARC R1 Rookie (TAG) Homologation application 18mm Crank Evolution application The Tech Committee recommend this item for approval by the NKC. 20mm Crank Evolution application The Tech Committee recommend this item for approval by the NKC. Head and Barrell Air cooled Evolution application The Tech Committee recommend this item for approval by the NKC. ARC M1 (Midget) Evolution application The Tech Committee recommend this item for approval by the NKC. ARC R1 (Rookie) Evolution application The Tech Committee recommend this item for approval by the NKC. ARC Spec 100 Air-cooled CES TAG/Direct Drive Engine Evolution application. The Tech Committee recommend the TAG engine only for Clubman Class. Note: The M1, R1, A1 and Spec 100 TAG are recommended because they meet the criteria required for The future of Junior Karting in Australia Short presentation by ARC on Junior Karting and making the transition to Senior with minimal expense. 05AD11_Addendum 11_ Evolution Class Item not discussed. Page 13 of 22

14 DPE Submissions: Documents attached Open Class Change to Rule (DPE Item 1) Proposed Amendment: Change to read: 4. BRP-Rotax DD2 engine 5. RM-1 kart (no reverse gear) Reason With many other Kart manufacturers now producing chassis for the DD2 engine, clarification is necessary that the DD2 engine is eligible even when not used on the Rotax RM-1 kart Change recommended as submitted by DPE Kart Formula Rule Brakes (DPE Item 2) Proposed Amendment: Brakes: The brakes must be effective and work on at least both rear wheels simultaneously. 1. Braking of the rear wheels ONLY except (a) the following classes:125 gearbox, ICC, Open class - with 2 stroke engines having a total capacity of 125cc or greater. Reason - Contradicts rule / This rule does not allow Rotax RM-1 karts that are 125cc and have front brakes. Change recommended as submitted by DPE Formula Rotax Addition to Rule (DPE Item 4) Proposed Amendment: Add: Cylinder base surface may be re-machined. Reason - Clarification. By virtue of the Piston travel rules, the cylinders can be machined, however we feel it is clearer to state this in the rules. Amendment to read: The cylinder base surface may be re-machined must remain perpendicular to the cylinder bore. Page 14 of 22

15 Formula Rotax and Page 194 Formula JMA Addition to Rule and (DPE Item 5) Proposed Amendment: Add: and Outer sealing surface of exhaust port may be machined. Reason - In the near future, BRP-Rotax now machine this area on all cylinders. Amendment to read: Due to manufacturing procedures some cylinders may have been machined on the exhaust flange. Formula Rotax and Page 199 Formula JMA Addition to Rule and (DPE Item 6) Rule one only exhaust gasket to be used with a maximum thickness of 2mm Proposed Amendment: Add and Only one exhaust gasket is permitted, maximum thickness of 2 mm. Reason - To clarify that only one exhaust gasket is permitted, as some people have used several, changing the overall length of the exhaust system. Recommended: Clutch support plate will increase in thickness and shoes will be thinner. Chapter 41, Midgets Update (DPE Item 7) Comer - Update on progress and final specifications of W80 Comer engines and cylinders. Reason - At the AKA AGM in Sydney last year, the NKC approved the introduction of the Comer W80 engine for the Midget class, subject to further testing and details of the final specifications. Kevin McKinnon and dpe have continued to test various configurations of the Comer W80 engine and just this week we have received preproduction engines and W80 kits for final evaluation. Kevin McKinnon to provide further information and specifications at the AKA meeting for NKC review/approval. NB. Comer has requested this engine be called the SW80 to reduce confusion with the W80 engine used in the USA etc That track testing be carried out at Geelong & Todd Road with Kevin McKinnon & Harold Arnett to observe to confirm parity. Check availability of head profile gauge for JMAX. These are available, DPE to forward 20 to National Office with TAS and NT to receive 1 and all other States to receive 2 each. Page 15 of 22

16 IKD Submissions: Documents attached Righetti Ridolfi Airbox - (IKD Item 1) This matter is placed on hold until the KIAA air box is submitted. Fuel/Fuel Containers Amendment to Rule Fuel Container (IKD Item 2) Not recommended. Approved Tyres Amendment to Rule Sections 1 & 2 (IKD Item 3) Passed to Admin Committee. Remo Racing: Document attached Leopard Class Thermostat Not recommended. To stay a non-tech item Sprocket To stay a non-tech item. Radiator ID Tag Not recommended Muffler Muffler to be identified by marking arranged by Remo Racing at no cost to the karter. Strike Products: Documents attached Clutch Specifications Rule 25.17(d) (Strike Item 1) That the 3000 rpm engagement speed be increased. Piston port engines have, at best, an average idle speed of around 2500 rpm. With the characteristic 4 & 8 stroke firing of these engines, it is very common for the engine to have peak idle speeds that can cause the clutch to engage. This is inconvenient for the karter in having to ensure that the brake is engaged and it could also be regarded as a safety issue. Another issue is that at 3000 rpm, a piston port engine has very little useful torque, making driving out of a stuck or partially bogged situation difficult or even impossible, negating the benefits of the clutch. It is suggested that an initial engagement speed of 4000 / 4500 rpm be considered. As the AKA specifies a centrifugal clutch, the clutch will quickly fully engage above this speed and not introduce any slippage at racing speed. There is evidence to suggest that the 3000 rpm engagement speed is regularly exceeded with a certain control class clutch design, but with no impact on the intent of the AKA for non slipping clutches. Page 16 of 22

17 Amendment to read Engines and Transmission: (d) Clutch: Must be centrifugal type only. Clutches must be AKA registered and can only be run on the engines they have been registered for. Whilst on level ground the kart (with driver seated in kart) must start to move under it s own power, when the engine speed reaches 4000rpm or less and dry clutch. Crankcases may be modified to permit fitting of clutch/starter assembly. Shoe Clutch Design (Strike Item 2) Withdrawn by Strike SSS Clutch To be fitted to ARC Spec 100 Engines (Strike Item 3) That the registered SSS clutch be allowed to be fitted to the ARC Spec 100 engines. This was the intent last year and was agreed to by Mr Frank Cesnik of Alltype, Clarification from ARC required. Evolution of SSS Clutch: Strike to submit documentation, sample sighted by Tech committee and recommended. Yamaha Freeline SL Clutch: Tech committee require fee and paperwork to be lodged with AKA before inspection. St George: PRD Fireball RK125WC Search of National Office files no records found. TAG Class Rules Chris Dell to come back to tech committee with squish measurement. KIAA/AKA Airbox Marking on air filter for identification purposes. 5mm hole to be drilled for draining purposes. 8mm hole in side flange for mounting purposes. No holes, tears or cuts in filter allowed. Compulsory for 1 January 2007 Tech committee recommend KIAA/AKA airbox. Page 17 of 22

18 Tech Committee Recommendations Chapter AFTERMARKET AND EVOLUTION ITEMS: (a) "An aftermarket component is a component that can replace an Original Equipment Manufacture ("OEM") component, but is NOT classed as a non-tech component". (b) An evolution change is a change to the design of an existing homologated or registered equipment and as such can only be submitted by the Manufacturer or Recognised Distributor. 1 All aftermarket and evolution items are required to have AKA homologation for use in AKA classes. 2 An inspection/registration fee of $ is applicable for each new item. This procedure is the same as for engines that have no FIA/CIK Homologation paper work. 3 If a manufacturer has to remanufacture an old die or tooling to improve quality and tolerances of parts or a better process of manufacture to improve production, this constitutes evolution. The new evolution part will be issued an AKA ID Number which will need to be registered/homologated/inspected at a cost of $ per item. 4 The registration period, after the National Karting Council approval, is 9 years with a review every 3 years. 5 The registration will take effect after: Approval is given by the NKC Homologation fees are paid. Samples, technical specifications and drawings are lodged with the AKA An acceptance letter together with the registration number will be forwarded by way of AKA letter authorising use on any AKA Track.. Chapter 35 JMA Add 5 th tyre option Change to Definitions: (uu) Tyres: An approved new or used tyre is one of the same type. Change to Addendum 8 Amend Rule Drivers receiving a replacement(s) will be required to start at the rear of the grid in their next competition, the only exceptions to this is a tyre with a manufacturing defect (as approved by the tyre representative and/or the Chief Scrutineer). Amend Rule Drivers receiving a new replacement(s) will be required to start at the rear of the grid in their next competition, the only exceptions to this is a tyre with a manufacturing defect (as approved by the Chief Scrutineer) and/or the competitor electing to use an approved used tyre. Page 18 of 22

19 Change to Chapter Change of Tyres: (Refer Chapter 23 or class technical detail for further information.) Unless otherwise specified elsewhere in these rules. (i) A Competitor is permitted to use only one set of prescribed dry tyres AND only one set of prescribed wet weather tyres in any class, at any event. (ii) Competitors may choose to use either the prescribed dry tyres or the prescribed wet weather tyres, according to track conditions, for any part of an event. (a) Kart set up restrictions apply, refer side pod rule R25.02(vii) and diagram refer E-E. (b) The mixing of dry and wet weather tyres on a kart during competition is not permitted. (with the exception of speedway karting) (iii) One (1) damaged or worn out tyre (front or rear) of both the prescribed dry and wet weather tyres per event may be replaced with the consent of the scrutineer, who will impound the replaced tyre. (iv) Damaged or worn out tyres (by way of force majeure) must be reported to and be inspected by the Chief Scrutineer prior to the kart leaving the grid/impound area, replacement(s) will be at the competitors cost. Drivers receiving a replacement(s) will be required to start at the rear of the grid in their next competition, the only exceptions to this is a tyre with a manufacturing defect (as approved by the tyre representative and/or the Chief Scrutineer) and/or the competitor electing to use an approved used tyre. (v) For State Championships and approved major events drivers receiving a replacement(s) will be required to start at the rear of the grid in their next competition, the only exceptions to this is a tyre with a manufacturing defect (as approved by the tyre representative and/or the Chief Scrutineer). Chapter 23 Proposed amendment General: Tyres shall be new or in good condition with no apparent flaws. No modifications to tyres are permissible. Outside diameter: 310mm max - 220mm min. Radial tyres are NOT permissible Tyre pressure bleed off valves are not permitted Page 19 of 22

20 Chapter 36 (ADDENDUMS REQUIRED FOR ALL PROPOSED AMENDMENTS TO CHPT 36) Proposed amendment Ignition: (i) Must be external rotor type and OEM supply. (ii) Both CDI and TCI ignition units as supplied by Yamaha are eligible. (iii) No modifications or internal repairs to the TCI unit are permissible. (iv) No CDI unit shall vary more than one (1) degree from the maximum advance to the advance found at 10,000 rpm. (v) It is permissible to repair/replace the connector for both CDI and TCI modules. IGNITION ROTOR INSERT DIAGRAM DIAGRAM IS FOR DIMENSIONAL REFERENCE ONLY Proposed amendment Engine: YAMAHA KT100J This section covers the Yamaha KT100J engine which must be maintained within the specifications approved by the AKA as outlined below. (SAME WORDING FOR ALL CLASSES) Proposed amendment Cylinder Head: 1 Must be original Yamaha casting. 2 The welding and re-machining of the Combustion area, gasket face and spark plug surface is allowable. Any additions/repairs must be nonadjustable and of aluminium material. 3 The combustion chamber style is required to have a squish band and chamber which are visually concentric to the spark plug. 4 The combustion chamber volume shall be a minimum of 11cc. Refer Rule The combustion chamber/squish area shall not protrude beyond the gasket sealing face of the cylinder head. 6 The spark plug thread may be repaired and shall retain its original position in relation to crankshaft axis. Helicoil and similar are permitted. 7 Maximum distance from sealing surface of spark plug to combustion chamber sealing face shall be 33.5mm. Page 20 of 22

21 36.12 Cylinder: Ports 1 All cylinder ports must be in as cast conditions. 2 No chamfer on port edges is permitted. 3 Maximum diameter of inlet port to be measured with a 19.2mm plug gauge. 4 Inlet tract length including gaskets from cylinder wall to carburettor gasket face to be 53.00mm minimum to 56.00mm maximum including gaskets in front and behind phenolic spacer CODE DIMENSION E 29.60mm max F 24.45mm max G 30.60mm max Port Split 6.00mm minimum High Point, exhaust to transfer. Port Split 7.00mm minimum Low Point, exhaust to transfer. Cylinder Machining: It is permitted to machine the head sealing surface, cylinder base and cylinder bore Crankcase: The crankcase ports will remain as cast. It is permissible to re-machine cylinder mounting face, crankcase half mating faces and crankcase mounting feet. It is permissible to repair crankcase main bearing recesses by welding or with metal inserts. The minimum chordal distance measured with a vernier calliper across the widest section of the transfer ports shall be 81.5mm minimum. (Refer diagram below). NOTE: Existing crankcases that are narrow may be spaced with a thicker gasket. Page 21 of 22

22 81.5 mm Min YAMAHA KT 100 J DIAGRAM IS FOR DIMENSIONAL REFERENCE ONLY Page 22 of 22