Questions & Answers
Rotax 125 MAX EVO Engine Series
1) Questions related to the EVO Engine’s technology…
Q: Why has the carburettor been changed?
A: Customer feedback of the current QS carburettor being used is that it is difficult to use in regard to throttle response and set up. The new XS carburettor is significantly improved in both areas.
Q: Does the XS carburettor provide greater engine performance compared to the QS Carburettor?
A: No, it will provide better throttle response and is therefore easier to operate for the driver.
Q: How difficult will it be to get the best setup for the XS carburettor and maximising performance?
A: The XS Carburettor is much less sensitive to changing weather conditions compared to the QS Carburettor – so there will be less need to change the jetting. Owners will be able to get the best out of their carburettor, without the need for help from expert carburettor tuners.
Q: Which items on the XS carburettor will be free within the RMC technical regulations for set up?
A: Size of the main jet and position of the jet needle.
Q: Is it possible to convert a QS carburettor to the XS specification?
A: No, this is not possible as the housing of the new XS carburettor is machined differently.
Q: Does the XS carburettor provide a better engine idle compared to the QS carburettor?
A: Yes, with the XS carburettor the engine will run for several minutes on idle without stalling. To stop the engine you will have to switch the ignition off. This will also save the battery life as the driver cannot forget to switch off the ignition.
Q: Is it possible to install the new XS carburettor to my existing engine?
A: Yes, the new XS carburettor can be installed to existing engines. A special introductory price is being offered when you purchase before 31st May, 2015.
Q: Why has the Ignition System been changed from Denso to Dellorto?
A: The technical possibilities of the Denso ignition unit (where the electronics are integrated inside the coil) are limited. It was not possible to integrate the electronic timing for the exhaust valve into the Denso ignition unit. Therefore, the new Dellorto Ignition System has been unified for the 125 MAX EVO Engine Series.
Q: Does the new Dellorto Ignition System provide greater engine performance?
A: No, the new Dellorto ignition system will not provide greater engine performance. The ignition timing for Junior Max and DD2 engines have been specifically programmed to improve reliability and reduce performance variation.
Q: Is it possible to manipulate the electronic box (ECU) of the Dellorto Ignition System?
A: State of the art protection systems have been utilised to avoid any manipulation of the ECU. For Rotax Pro Tour events an ECU tester will be used to check the technical conformity.
Q: Why has the ON/OFF Start switch and button been changed?
A: The mounting of these components has been varying from chassis to chassis. The new battery holder with integrated OFF/ON/START switch and starter relay enables a standardised fitting on the left side of the seat with improved durability of all components.
Q: How can I charge the battery with the new combined battery holder?
A: The combined battery holder also includes the connector for the battery charger.
This means it’s possible to charge the battery without removing the battery cover.
Q: Is it possible to combine the new battery holder with the Denso ignition system?
A: No, this is not possible.
Q: Is it possible to combine the new Dellorto Ignition System with the old ON/OFF Start switch and button?
A: No, this is not possible.
Q: Is it possible to install the new Dellorto Ignition System to my existing engine?
A: Yes, specific upgrade kits will be offered.
Q: What was the reason for the introduction of the Electronic Power Valve?
A: The proper function of the current pneumatic Power Valve is dependent upon too many variables (eg: temperature, carburetion, sealing between cylinder and exhaust system, condition of the isolating matting in the exhaust system). The new Electronic Power Valve is dependent on the rpm of the engine only.
Q: How does the Electronic Power Valve work?
A: The Electronic Power Valve is controlled and triggered by the RPM of the engine. At Engine Start-Up the Power Valve is open, meaning it will start and idle easier. An Electronic Control Unit (ECU) then opens a modulating valve to allow vacuum pressure from the crankcase to pull the Power Valve closed at exactly 3,000 RPM. Once the engine reaches the driver’s chosen RPM setting, the ECU then deactivates the modulating valve, and the compression spring pushes open the Power Valve. Upon return to the in-grid the engine will continue to idle once below 3,000RPM again, and the Power Valve returns to the open position.
Q: Does the Electronic Power Valve provide greater engine performance?
A: No, the exhaust port timings of the Electronic Power Valve in the open and closed positions are identical to the current pneumatic power valve. The electronic timing provides constant function, reducing variation in performance characteristics.
Q: Is it possible to install the Electronic Power Valve to my existing Senior Max or DD2 engine?
A: Yes, specific upgrade kits will be offered.
Q: Is it possible to install the Dellorto Ignition System but still use the Pneumatic Power Valve with my existing Senior Max or DD2 engine?
A: Yes, it is possible.
Q: Is there any adjustment for the timing of the Electronic Power Valve?
A: Yes, the system offers two different opening/closing points (7,600 RPM or 7,900 RPM in Senior Max and 8,800 RPM or 9,100 RPM in DD2). This allows the driver to set the Power Valve to his/her personal preference.
Q: Does the new exhaust system offer greater performance?
A: No, the dimensions that would affect the performance have remained unchanged. The focus on the new exhaust system has been on improving durability and lowering the sound emissions.
Q: Is it possible to install the new exhaust system to my existing engine?
A: Yes, and a special introductory price is being offered when you purchase before 31st May, 2015
Q: Have the fixation points of the new exhaust system been changed?
A: No, they are the same.
Q: Are the sound emissions of the new exhaust systems less?
A: Yes, up to 1 dB.
Q: Is the isolating mat in the silencer the same as the current isolating mat?
A: Yes
Q: Are the silencers of the new exhaust systems identical?
A: Yes
Q: What is the benefit of the new exhaust sockets?
A: The new exhaust sockets with integrated gasket ring offer better sealing between the cylinder and the exhaust pipe. Perfect sealing is essential to get the best performance from the engine.
Q: Is it possible to install the new exhaust sockets with gasket ring to my existing engine?
A: Yes, the new exhaust sockets fit on existing and new exhaust systems.
Q: Will the new piston provide better engine performance?
A: No, but the required running in period will be shorter; therefore the engine will reach its optimum performance sooner. The new profile of the piston will also reduce the wear rate and therefore increase the durability of the piston.
Q: Is it possible to install the new piston in my existing engine?
A: Yes, it is recommended only at your next engine rebuild.
Q: Has the piston ring of the new piston also changed?
A: No
Q: Will the new Conrod provide greater engine performance?
A: No, but the durability will be significantly improved. Also the reduced tolerance of the length from the center of the big end to the center of the small end will contribute to a more equal performance.
Q: Is it possible to install the new Conrod into my existing engine?
A: Yes, the new conrod kit will also fit existing crankshafts, recommended at your next engine rebuild.
Q: What are the recommended hours between engine rebuilds for the new piston and
conrod?
A: The recommended interval between engine rebuilds for the new piston and conrod is 50 hours of engine operation. At least after 50 hours the engine has to be disassembled and checked. Depending on the wear rate different components might have to be replaced.
Q: What is new on the crankshaft?
A: The fit between the main bearing seats and the main bearings have been optimised. The engine will reach its maximum performance with a shorter running in period.
Q: Is it possible to install the new crankshaft into my existing engine?
A: Yes, it is possible, but only recommended if the existing crankshaft has reached its wear limits.
Q: What is the difference between the new black crankcase and red cylinder head cover compared to the current components?
A: There is no technical difference except the colour. The black crankcase and red cylinder head cover only provide the engine with a different appearance.
Q: Is it possible to install the new crankcase and cylinder head cover on my current engine?
A: Yes, it is possible, but technically there is no need.
2) Questions related to specific engine types…
2.1) 125 Micro MAX
Q: Which upgrades for existing engines are mandatory or recommended?
A: Mandatory upgrades are:
- 18 mm exhaust socket with gasket ring
- Perforated tube silencer with 22 mm elbow
- Squish gap
A: Recommended upgrades are:
- XS carburettor
Q: Is it necessary to install the new Dellorto Ignition System to my existing engine?
A: No, it is not necessary as the Dellorto Ignition System will provide the same engine performance as the existing Denso Ignition System.
Q: What is the benefit of the new Dellorto Ignition System?
A: More equal engine performance, improved throttle response, easier to use, less manipulation possibilities.
Q: Is there a stop sleeve in the new XS carburettor to limit the opening of the carburettor slide?
A: No, but it is recommended to set the accelerator pedal stop to a 60-80% opening of the carburettor slide (depending on driver’s pedal length preference).
Q: Will a different maximum opening of the carburettor slide have an impact on the maximum performance of the engine?
A: No, but the improved ease of applying the throttle might improve lap times.
Q: Will the new 125 Micro MAX specification result in faster lap times?
A: Yes, but just slightly.
2.2) 125 Mini MAX
Q: Which upgrades for existing engines are mandatory or recommended?
A: Mandatory upgrades are:
- 20 mm exhaust socket with gasket ring,
- Squish gap
A: Recommended upgrade are:
- XS carburettor
Q: Is it necessary to install the new Dellorto Ignition System to my existing engine?
A: No, it is not necessary as the Dellorto Ignition System will provide the same engine performance as the existing Denso Ignition System.
Q: What is the benefit of the new Dellorto Ignition System?
A: Improved throttle response, easier to use, less manipulation possibilities.
Q: Will the new 125 Mini MAX specification result in faster lap times?
A: No, the lap times will be slower and will be in between 125 Micro MAX and 125 Junior MAX.
2.3) 125 Junior MAX
Q: Which upgrades for existing engines are mandatory or recommended?
A: Mandatory upgrades are:
- No mandatory upgrades required
A: Recommended upgrade are:
- XS carburettor
- Dellorto Ignition System
- New battery holder
- New exhaust socket with gasket ring
Q: What are the benefits of these new upgrades?
A: Improved throttle response, easier to use, improved engine characteristic in the rpm range from 12,000 – 13,000 rpm.
Q: Will the new 125 Junior MAX specification result in faster lap times?
A: With the new specification the engine is significantly easier to set up and get the best performance. This will enable drivers with less set up experience to achieve the best performance.
2.4) 125 Senior MAX
Q: Which upgrades for existing engines are mandatory or recommended?
A: Mandatory upgrades are:
- No mandatory upgrades required
A: Recommended upgrades are:
- XS carburettor
- Dellorto Ignition System
- New battery holder
- Electronic Power Valve
- New exhaust socket with gasket ring
Q: What are the benefits of these new upgrades?
A: Improved throttle response and easier to use.
Q: Will the new 125 Senior MAX specification enable faster lap times?
A: With the new specification the engine is significantly easier to set up and get the best performance. This will enable drivers with less set up experience to achieve the best performance.
2.5) 125 MAX DD2
Q: Which upgrades for existing engines are mandatory or recommended?
A: Mandatory upgrades are:
- No mandatory upgrades are required
A: Recommended upgrades are:
- XS carburettor
- Dellorto Ignition System
- New battery holder
- Electronic Power Valve
- New exhaust socket with gasket ring
Q: What are the benefits of these new upgrades?
A: Improved throttle response and easier to use. The DD2 specific ignition timing will make the engine less sensitive to detonations at critical engine operation. This will increase the durability of components and reduce cost of operation.
Q: Will the new 125 MAX DD2 specification enable faster lap times?
A: With the new specification the engine is significantly easier to set up and get the best performance. This will enable drivers with less set up experience to achieve the best performance.
3) Questions for Karting Federations…
Q: Rotax is known for stability. Why have these changes been introduced?
A: Stability is top priority for Rotax. All technical changes have been introduced in favour of our customers to improve the ease of use and reduce cost of operation. The new specifications will be easier for less experienced drivers, and requires less support from experts. Consequently this will reduce the cost of racing a Rotax and assures equal opportunities for everyone.
Q: Why was the industry not informed about these changes in advance?
A: Rotax set a communication schedule to ensure a professional market introduction of the new upgrades. As a result of these changes, the Rotax sales network will offer upgrade kits to customers with existing engines at a special introductory price, purchased before 31st May 2015.
Q: Will all drivers have to purchase the new EVO Engines?
A: No, for every existing engine mandatory and recommended updates have been defined (above).
Q: Will drivers with existing engines still be competitive?
A: Yes, if they are familiar with fine tuning their engine (which is sometimes difficult).
Q: Are existing engines still allowed to be used in the Rotax Pro Tour?
A: Yes, the Rotax Pro Tour technical regulations will allow for the use of both existing engines and new engines, as well as existing engines with different stages of upgrades.
