Tag Archives: tonykart

Track Test: 1978 Kestrel v 2005 Tonykart

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then and now
1978 Kestrel v 2005 Tonykart

With the sport of karting celebrating its 50th birthday in 2006, it seemed an interesting exercise to pit a kart from the earlier days of the sport against its contemporary counterpart to see what progress has been made in kart development in recent decades. Using the driving services of Buckmore Park Kart Shop co-owner David Catt, a fully restored Sisley Kestrel/TKM FF99TT 100 National, circa 1978, and a 2005 Tonykart Venox UK Rotax MAX outfit were assembled at Buckmore Park for a back to back test session to establish what conclusions might be drawn from nearly 30 years of development. When the Kestrel kart was new, 100 National was the backbone of British karting, the Rotax MAX of its day.

Manufactured in large volumes by Bill Sisley’s Sisley Karting empire, some 2,500 Kestrels were sold during a ten year period from the early seventies into the eighties. While Johnny Herbert is of course the most notably successful driver who campaigned in one 3of these karts (to win the 1979 British Junior Championship) the Kestrel kart, over a ten year period, achieved ten outright British Championship wins campaigned by drivers such as Tim Davey, Tim Harvey, Lee Cranmer, Wayne Homer, Gary Prior, John and Richard Weatherly and Mark Tredwell among others. While the Kestrel is powered by a late ‘70s aircooled TKM FF99TT rotary valve producing approximately 19bhp and runs on rock hard, skinny Goodyear Blue Streak tyres, the Tonykart we used, kindly loaned by The Kart Shop, featured the hugely popular water-cooled Rotax FR125 MAX engine producing around 28bhp and running on Vega SL7 tyres. The karts look completely different. The Kestrel with no bodywork looks very narrow, especially on the skinny tyres, and while the Tonykart sports a 12mm disc and 50mm axle, these components on the older kart are exactly half these dimensions. The Tonykart subsequently looks a lot more aggressive with its liveried bodywork and fatter tyres. Out on the track, the Kestrel proved to be something of a surprise. Despite being some 3 seconds slower than the Tonykart, the whole experience was a lot more raw and exciting. You really felt part of the kart. Despite a lack of grip compared to the modern machinery, the Kestrel was superbly balanced and very predictable, especially on the downhill section of the circuit.

The Tonykart by comparison was very refined and because of the engine’s watercooling, more sophisticated exhaust and rev limiter, was a lot quieter. The kart drove with a precision that was missing in the Kestrel and was a lot easier to place on the track thanks to the superior grip. The engine is a completely different animal but provides strong performance through the entire rev 4range, the ‘70s motor being far more peaky with a narrower power band. David ran the older kart very rich and was also wary not to place too much stress on the brakes and the tyres but he reckoned by leaning the motor off, becoming more acquainted with the Kestrel and replacing the 25 year old tyres with something newer, it would easily be possible to get within a second of the modern kart’s times. The easiest way to contrast the experience would be to liken it to driving a 1973 Porsche 911 and a 2005 model. Both provide excellent fun and driving pleasure, the earlier example air-cooled and more crude but lighter and perhaps more sensational while the newer model does the same thing but with more finesse, precision and refinement. Whether that is to the detriment of the overall driving experience will always be up for debate.

Track Testing: Tony ROK

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Why a Tony ROK

After months of organization and setting up of the new “Track Testing” column, me and my photographer managed to visit the great Tony Kart Company and collect our Tony EVR ROK  engine kart. We have chosen this solution as it seems one of the easiest ways to start karting with a very performing chassis (Tony Racer EVR) and a very reliable TAG 125cc two-stroke engine (Vortex-Rok).

From 2003, the year of its establishment, until today the Rok Cup has won the trust of many fans in more than 35 countries all over the World. Rok has been a good novelty since it has been the first real single make solution directly followed by the company.  Start has been in Italy at first, then in Europe. After that it crossed the oceans and has arrived in South Africa, Asia and America. All the national champions, in every category, win the possibility to race in the Rok international Final, which is the CIK-FIA event closing the Rok season every year. The 280 best Rokkers coming from all over the World take part in this race and in the end we discover who the absolute champion in each category is: Rok, Super Rok, Junior Rok and Mini Rok.

Rok engines

Rok engines are a complete family of four different versions for the same number of classes: Mini Rok, Junior Rok, Rok and Super Rok. Mini Rok is the entry level for very young drivers. Vortex has developed two Mini Rok engines:
Mini Rok MINI 60 and Mini Rok BABY 60: the two versions differ from one another in carburettor and exhaust.

MINIROK BABY 60: supplied with carburettor of 14mm diameter and baby exhaust (reduced power), dedicated to the youngest; it is the entry level in the karting world.

MINIROK MINI 60: supplied with carburettor of 18mm diameter and mini exhaust; it is the second step in competitions, usually from 9 to 12 years old drivers.

 Rok range


We have decided to go for the ROK for our track testing since it is a good compromise between performance and reliability. To my opinion it probably represents best the aim of Vortex in creating the ROK World.

Junior ROK and ROK are based on the same engine except for the exhaust curve. Engine is a 125cc single-cylinder 2 stroke with reed valve admission in the crankcase. It is mixture lubricated and liquid-cooled with integrated water pump. It is offered with a digital ignition and an integrated electric starter, which uses a dedicated battery. It is provided with a balance shaft which reduces vibrations. A centrifugal dry clutch makes it possible to keep the engine on even when the kart is still.


Mini ROK Junior ROK ROK Super ROK
Bore (mm) 42.10 54 54 54
Stroke (mm) 43.00 54 54 54
Displacement (cm3) 60.00 123.95 123.95 123.95
Cooling Free air liquid liquid Liquid
Intake Piston port Reed valve (length 63.5 mm x height 25.5 mm) Reed valve (length 63.5 mm x height 25.5 mm) Reed valve (length 69.5 mm x height 25.5 mm)
Max torque (Nm) 19.6 at 10,000 19.6 at 10,000 20.2 at 11,500
Max power (HP) 10 at 10.300 19 at 11.500 29 at 10,500 36 at 12,500
Max revs 13,800 13,800 16,700
Carburettor 18 mm (14 mm for Baby ROK) Dell’Orto VHSH 30 mm Dell’Orto VHSH 30 mm Dell’Orto VHSH 30 mm
Fuel pump Dell’Orto Dell’Orto Dell’Orto Dell’Orto
Exhaust system With intake sylencer With integrated silencer and depower system With integrated silencer With integrated silencer
Drive Centrifugal Dry clutch Centrifugal Dry clutch Centrifugal Dry clutch Centrifugal Dry clutch
Lubrication 2-3% (Rok Lube or Elf 909 HTX) 3-4% (Rok Lube or Elf 909 HTX) 3-4% (Rok Lube or Elf 909 HTX) 6% (Rok Lube or Elf 909 HTX)
Weight 8kg 17,5kg 17,5kg 15 kg
Ignition system Electronic Selettra or PVL Electronic PVL Electronic PVL Electronic PVL
* Price (in Euro) – with carburettor, fuel pump, exhaust muffler, radiator & supports, thermostatic valve, cooling system pipes, on-off push-button panel, battery, battery support, electric plant, intake silencer. 1,950 + VAT 1,950 + VAT 2,400 + VAT

Prices are only indicative and subject to changes.


Super ROK is the ultimate evolution of the ROK engine by Vortex, conserving many of its important characteristics, but featuring an amount of innovations. Not changing the displacement of 125cc and the reed admission in the crankcase, the reed block is now bigger, and the carburettor is still a 30mm diameter VHSH by Dell’Orto. The new cylinder, always with liner, has a 5-transfers scavenging, and the 3-ports exhaust is provided with pneumatic power valve. The digital ignition has a different advance diagram; the exhaust plant is new in design with integrated silencer; the rotor of the centrifugal clutch is now monolithic.

The Chassis

RACER EVR Tony Kart freno BS7

Together with our Rok engine we have chosen one of the most performing and successful chassis from Tony, the RACER EVR. This chassis is available for both KF and KZ categories and represents the natural evolution of the EVXX the chassis that allowed Tony Kart to win all the most noble CIK-FIA competitions, including the World Championship, in these last years. The EVR is composed by a frame realized with Ø 30 mm tubes, which determine the kart to be more “free” when exiting corners. The Racing version is equipped with the new M4 bodywork and the new WTD (Wind Tunnel Design) stickers. The design of the new plastics resulted from several hours spent in the wind tunnel. The plastics have been optimized in order to reach an optimal aerodynamic penetration and to allow the air flow to invest the engine, the radiator and the brake systems in the best way during the races.

Homologation : CIK FIA 56/CH/14
Frame diameter : 30 mm
Wheelbase : 1050 mm
Stub Axles : OTK HST
Braking System : OTK BS5 – BS6 – BS7
Steering wheel : OTK rivestito in alcantara
Wheels : OTK MXP in Magnesio
Side Boxes : OTK M4
Seat : OTK a fondo piatto


This top chassis is provided with OTK magnesium accessories. The OTK brake systems BS6 and BS7 are still one of the most important features characterising both the former model and the new one. Front brakes are also included and will be tested to understand if and when these brakes are useful and performing for a driver.

Base setup for Tony EVR is neutral height front and rear and neutral camber and caster. Front torsion bar must be flat and rear bar eliminated. Rear carriage width will be to maximum limit at 140 cm and front carriage width will be adjusted with a small and a large spacer, equal to 2.5 cm additional width. Convergence must be 1 mm “open” at the front, so 0.5 mm per side. Seat will have stiffness bars o both sides, at least one, possibly two per side.

Rear axle stiffness is determined by five different materials indicated on the axles as HH, H, N, Q and U, starting from the stiffest to the softer. Base setup uses the N axle.

Prices of EVR chassis is 4,490 Euros VAT included, including front brakes, magnesium accessories and seat (price only indicative and subject to changes)

Tony Kart factory: a look inside

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The tubes as they arrive at the factory

The Company

The company of Prevalle (Brescia), in the centre North of Italy, has been in the last years leader in the karting World, and has strongly contributed to making the history of karting in Italy, in Europe and in the World. Chassis with Tony, Kosmik and FA – Fernando Alonso – (the two latter born respectively in 2003 and 2006), engines with Vortex/Rok, and accessories with OTK, make Tony Kart Company one of the largest karting companies in the World.

Tony Kart was born in 1958 thanks to the passionate initiative of a great mechanical craftsman and it was one of the first companies which followed the American karting phenomenon, creating a chain production of chassis for go-karts. In 1983, with a new management, Tony Kart came to a turning point and the new company received a radical acceleration; the factory, in virtue of new investments on research and sophisticated manufacturing, engineered and started making methods of production even more efficient. After this rapid growth and modernization, Tony Kart quickly came to the forefront of the karting scene, conquering lots of International Titles starting already from the ‘80s.

Automatic bending to the required angles

What led Tony Kart to its great success the most is the non-stop technological development in accordance with the binding demand imposed by high level competitions. Two fundamental aspects allowed the factory to do the qualitative leap, guaranteeing the constant planning and productive development process: the employment of a highly qualified staff and the automation of the production phases. In fact, robots controlled by sophisticated software permit today high productive standards with quality near to perfection. Nowadays, in order to offer chassis more and more innovative and competitive, Tony Kart engineering department is always experimenting with new solutions according to the latest technological innovations present on the market. The essence and peculiarity of Tony Kart production are represented by the passion for mechanics and planning innovation.

The sections ready to be welded

In the late ‘90s Tony Kart concentrated in new fields as well, in conformity with the modern concept of factory. Some important sectors are now spreading in Tony Kart, such as marketing, communication and any type of multimedia support. These instruments allowed the sales network to extend and improve so much that it is now developed in 60 Countries all around the world. 
During these years, Tony Kart has been involved in exciting and prestigious cooperation relationships with top characters and associations of the international motor-sport scene. Last but not least the collaboration with the Senna Institute, which led Tony Kart to the creation of the jewel “Ayrton Senna Racing Collection”.

A new innovative production site was built and is fully operational from early 2000.
The factory is running its business based on a modern management system, skilfully coupling the numberless sporting victories gained so far with the perfect company administration.

From ‘60s till now, go-karts characterized by the unmistakable “green Tony” raced and won on lots of different tracks all over the World. Listing all titles won in years by Tony would bring to an unending paper, but what is interesting is that F1 drivers today racing and winning in the number one automotive racing championship, have learned and put the basis of their driving skills racing on a Tony kart! Jarno Trulli winner for three consecutive years of major International races such as Japan Grand Prix, World and European Championship, Japan World Cup, North America Championship and Oceania Championship. Sebastian Vettel also won with Tony in 2001 the Junior World Championship. Amongst British drivers racing and winning with Tony XXX.

This year Tony has started with success. WSK Euro Series, the most important European event, has in fact seen, on the International Circuit of La Conca, the success of Tony Kart-Vortex in the master category, Super KF, and in KF2. The protagonists of this success were Marco Ardigò and Ignazio D’Agosto.

The Visit

A robotic welding machine

A visit to Tony Kart company is like entering the Olympus of karting, where all the more advanced technology and know how of karting is preserved. A modern and very “clean” entrance introduces me and my photographer to our visit at Tony. Skipped the reception we quickly move to the heart of the Company, where an incredible number of shining chassis are aligned, mostly green, some blue and others cyan, respectively Tony, Kosmic and FA chassis. An incredible vision! All the atmosphere is more of a laboratory then a kart industry. It is clear how the main kart company has changed in the last years from a handcraft company to a real modern and international organization.

Production phases: From steel tubes through welding to chassis

The welds pre-powder coating

We then start our tour, considering that where we have arrived is the end of the production line for chassis. These are in fact completely built inside the company except for raw materials such as steel (tubes), magnesium, aluminium and plastic materials, which are then machined or stamped by Tony to build many accessories. Externally also colouring of chassis and components is applied.

So let us start from the steel tubes. These are carefully chosen in diameter and wall thickness and the specific information on the steel alloy with which they are produces is cautiously kept secret. The tubes are then cut to the requested length and bent to the right shape, using specific machines.

Assembly of the chassis

Following step is of dramatic importance with the tubes being put together on what is called a mask, which keeps all parts in the right position, as they will be finally displaced on the welded chassis. The mask is then introduced in a numerically controlled welding machine that has the possibility to weld with fantastic precision and speed all the tubes together. The mask rotates around the longitudinal axis of the chassis so weldings can be completed acting from over and under the kart. In around 45 minutes the robot welds all the tubes of the chassis and the base of a new kart is created. All weldings are applied using MIG (Metal Inert Gas) solution, which is a string welding with protective gas that avoids oxidation of hot metal with the air. This could in fact weaken the welding. This process and the use of an electronic robot with numeric control gives the weldings a very high and constant quality that permits to have great performance on all chassis produced. A visual prove of this is the very uniform “look” of the weldings that can be well seen before the chassis are painted. Another confirmation comes from the fact that Tony kart uses exactly these same chassis for its racing team and drivers. Only differences are the weight distribution measurements done specifically for each driver by seat adjustment and eventual addition of weights, and telemetry system application.

Also all other components are built internally in Tony Kart such as brake and accelerator pedals, steering columns, wheels, rear axles and rear bearing supports. All is finally collected together in a specific area and chassis are completed, by mounting all these additional elements manually by the operative staff.

What is then done externally to the Company is colouring of both chassis and components. All aluminium and magnesium components are coloured and anodized. Also the study of plastic front, rear and lateral bumpers is brought forward in Fondmetal Wind Tunnel.

At the end of the day Tony is able to produce a high number of new high quality karts per day and sell them all around the World, such as in US, Europe and Japan, but also boosting sales in Asia, such as in Cina and Malesia, and also South America, specifically in Brazil, Argentina and Costa Rica.

The finished product

From Tech Talk to Track Testing

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After many issues with all there was to say about theory and practical tips on kart chassis and engines, we are now starting a new Era with practical track testing on the grid from next month. The new column, “Track Testing”, will put together brief descriptions of how to work on set up and maintenance of chassis and engine, and will then apply them on track. Sensations, lap timing, engine performance, tire temperature and wear, chassis setup, engine carburetion, driving techniques, will all be first explained and them tested in real time.

Partners: Vortex Rok and Tony Kart

A Vortex Rok powered Tonykart will be used for our track testing

To start in the most professional way we have asked a great kart company to be our partner for this new column. So Tony Kart was chosen and accepted the offer, together with Vortex, to be our partner and guide with Tony chassis and Rok engine. We will be collecting a brand new Rok Cup before next issue and will start describing the kart that will be with us in our future track testing along 2010. We have chosen a solution with Rok kart that puts together reliability and performance and is surely one of the best ways to enter karting World. We will once in a while also test new chassis and engines of other brands and categories that are particularly innovative and relevant to the market. Also we will try to evaluate other kart and engines of specific marque trophies.


From next month we will try to go through all the steps needed to buy a kart (a Rok in this specific situation), evaluate costs, basic setup options, such as seat adjustment and positioning, carburetion, tire pressure, running in of the engine and tires, and progressively follow all steps needed to understand a kart in all its parts and settings. You will each month have the opportunity to find out, understand and possibly test solutions on your kart just as we will on track. Just read us and you will see.

We will start with a visit to Tony Kart company and presentation of Tony chassis and Vortex Rok engine, with detailed description of both elements, just to be ready with the right information to start our “trip” together.

Mainly the idea is to start from basic setup and start making changes to some parameters of chassis and engine to really feel the difference both in driving sensations and performance lap times). We will go through all possible parameter changes and will verify all solutions for different track conditions, track conformation and temperature weather consitions.

Monthly discussion

Questions from you, your sensations and opinions will surely be read and replied to each month. We will be able to exchange thoughts and impressions to grow our experience and become more and more competitive on our karts. It is true in fact that even though setup and regulations have very specific and scientific solutions and explanations, often a change for example of track and tire conditions can generate different results in setup adjustments. Moreover even different driving techniques and characteristics may generate different setup needs for best performance. So discussions and different opinions will be much appreciated and eventually published on Karting Magazine.


We will be testing on different tracks in Italy, taking good advantage of the great Italian weather, and will test monthly new setups, adjustments, driving techniques, engines performance. We will most of the time test on tracks in the centre of Italy, for logistic simplicity, but will also once in a while move to the most important tracks in Italy, where main International races take place, such as Parma, Lonato, Sarno and Jesolo. Using though same track for more testing will give us the opportunity to test on the same asphalt and conditions and make correct comparison tests.

Track Testing

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DSC_5575When carburation is out Recently we did a good days testing with our new Super Rok Tony EVRR chassis on a very hot day at the Pista dOro in Rome. This is a medium-slow track with lots of curves and was ideal for comparing our Super Roks performance against that of the Rok outfit we used last year.

Session 1
We started with a transmission ratio of 11:87 and with the Bridgestone tyres set at 0.5 bar. Set-up on our Tony chassis was 140cm rear carriage and minimum front width. We used the standard camber and caster settings, and the front and rear heights were also set at average values.

Our initial laps immediately displayed the fantastic push of the engine, much more evident this time than at our first test at Lonato since the transmission ratio then was much shorter (11×80). Set-up however was not really ideal, most probably because the seat position is not yet set at its best and also the steering wheel has surely to be adjusted. This we will fine tune for future tests.

Still, our first laps were quite fast on a very slippery track with no rubber. Our fastest lap of 48.85s was already interesting as in the same track conditions we would have been running close to 50s with the Rok. However, our best maximum revs as indicated on our AiM telemetry system were just 15860rpm, compared to the limited maximum indicated by Vortex for the Super Rok of 16700rpm. We felt the engine had great push at low revs, but on the tracks only straight we felt that at mid revs the acceleration and push were weak and the engine had difficulty increasing revs. Since everything seemed to be working properly the first thing to check was the carburation. I stopped and we unscrewed the spark plug to check the situation inside the cylinder. With a flexible stick-light it is possible to illuminate the combustion chamber and verify if there is too much or too little oil covering the piston head, indicating respectively rich or weak carburation. This adds more precision to a simple check of spark plug appearance.

Our check confirmed our thoughts as the piston and spark plug were very wet with mixture. We then opened the carburettor and checked that out. We changed the carburation setting by moving the ring along the needle to reduce richness. The ring setting was on medium so we altered it to the weakest setting, away from the tip of the needle. The jet was left unchanged.

Session 2
Back on track and now the engine was behaving better at mid and high revs, while at low revs the push was unchanged. Lap times improved immediately and, on lap 2, after the tyres had warmed up, I stopped the watch at 48.53s and went on improving with a best time on lap 5 of 48.40s. Maximum revs reached 16010rpm so we were still missing up to 700 revs.
We were now at the limit of carburation and were still missing something at mid revs that was the cause of the limited maximum revs at the end of the straight. Since we had no suitable alternative jet with us to further adjust the carburation we had to find other solutions, or at least try.

We wanted to increase maximum revs somehow so we shortened the transmission ratio to 11×89, still far from our objective of reaching at least 16500rpm, knowing anyway that at Pista DOro it is not really necessary and efficient lap time-wise to reach the engines real maximum revs.

Session 3
We tried the new set-up and lap times did not really change. On the one hand the shorter transmission ratio should have brought around 370rpm more with the same maximum speed at the end of the straight, but on the other hand the fact that mid revs came at a lower speed slowed the kart down earlier along the straight with no real final benefit. Even some tuning of the exhaust valve to help torque at high revs did not really work out. Lap times remained almost unchanged at a best of 48.50s and there was also some slight deterioration of the tyres.

Generally an engine can work only well with the correct carburation. The Super Rok has shown itself to have much more performance than the Rok, but also more sensitive to carburation, which has to be looked at with great care. Changes to the transmission ratio, exhaust valve or other alternative ways to correct engine performance do not really work. Such fine tunings can only be done after the carburation is correctly set.

2011 karts

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WSK Nations Cup La Conca November 2010Maranello RS9
The major additions to the Maranello this year is the variable wheelbase system which is available on all karts, and the RS9-S which is an evolutionary design to take advantage of harder tyres and colder conditions in the UK.

Main Features

Contact Details

Cruiser V
010 World Championship winning Cruiser V has had only very minor changes to the seat supports to allow for easier seat fitting without affecting the karts performance on track.

The 2011 Cruiser V chassis comes with 30 mm geometric tubing. This chassis brings new solutions such as the axle bearings supports and new SH2 stubs which increase the balance between the front and the rear of the kart.The 2011 Cruiser V chassis is equipped with original brake systems of new homologation called R1, R2 and FRM.R1. Such brake systems are composed by mono-block brake calipers with radial support, new generation floating brake disks and brake pumps for oil recovery.

The Storm kart has been updated in time for the 2011 season with new materials being used for some of the components, including the tubing of the frame.

Main Features

Contact Details

Wright Mercury
Wright have developed two new karts designed specifically for TKM and for Rotax Max. The Mercury TKM is the first TKM-specific chassis since the Braga, but it’s now developed to take advantage of the new TKM chassis rules. The Max version has been designed to take full advantage of the Mojo tyres.

Main Features
Constructed from specialised Italian 30mm chrome-moly tube.

A unique ride height, “Notch” system for the rear axle, allowing precise 2 position ride height adjustment in just a few seconds.

Front ride height has five settings for accurate adjustment.

A four position steering column is coupled with a three position stub giving the steering response and severity the widest possible spectrum of adjustment.

Caster/camber kits and interchangeable Stub axles mean you can tailor your Wright “Mercury” to your exacting standards whatever your requirements.

Removable front bumper hoops allow a “Crumple Zone” to protect the chassis in the event of heavy impact.

Max version weighs 44kg without engine and tyres.

Contact Details

Already raced at the WSK Nations Cup and the SKUSA SuperNationals, the EVRR won KF2 at the WSK and KZ2 in Las Vegas.

Main Features
The bearing carrier supports are the same as 2010 with ride height but not wheelbase adjustment, but they are now one piece which should add to the structural stiffness. There is also now a KZ version with a higher range of ride height adjustments.

THe new bearing carriers have a variety of positions for seat stays.

THe shape of the fuel tank has been changed to lower the centre of gravity, which has also led to a change in the shape of the steering column support.

THe lower steering column support has been changed so foot supports can be moved.

There is a new steering wheel available with a new spoke structure and a grippy covering, as well as brackets for PI, AIM and Unipro data loggers.

Contact Details

Track Testing: Rok long test final results

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brake padsWe have been testing and testing with our Rok engine, mounted on a Tony chassis, and after months of testing we can recap this long period.

Start and mode of testing

We started at the beginning of the year with our Tony Rok that had raced twice and was in good conditions, maybe with about 2 hours of running already. We decided to proceed with our testing month after month without doing any great maintenance, apart from using chain grease and putting mixture in the tank. All the rest was limited to chassis setup, tires substitution and some cleaning. This was done since we wanted to find out the reliability of such kart, especially the engine, for someone who had no idea at all on how to maintain a kart. Even carburetion was always kept at its standard value…and this worked all year perfectly, until our latest test, done in very extreme conditions

Long test diary

First of all we must say that our long test had the aim to verify the duration of the engine, as already said without any maintenance and tuning (carburetion first of all). So we went along with our testing month after month and were waiting for something to happen to the engine sooner or later. What was surely incredible was the fact that it was possible to run each time with the same carburetion from March until now, with extremely great temperature and humidity differences. Engine worked always well, with good performance and incredible reliability, something I never experienced with 100cc direct drive engines or any other kart competition engine.

From March to May – total 7 hours, no problem at all!

We ran with the Rok about 5 hours of testing, which had to be added to the 2 hours of racing done before we received the kart from Tony. Never a problem in this phase. We just took the kart to the track, put mixture in the tank, grease on the chain..and ready to go! This is something that you cannot really afford with other competition engines, and surely puts in evidence how good such a solution is for any driver who wants to use a lot his kart and eventually do some racing, always with good performance but no real fuss to look after the engine.

June to September – 11 hours, just a spring of the clutch braking. Rear barking pads worn

Still very good functioning, also the chassis was incredible. The Esprit adapted to all tracks with great easiness. No setup change or only slight adjustments were needed for good performance. Any regulation of setup also gave very good reactions to behavior of the chassis indicating wide range of possibilities to adjust the kart to driver’s needs.

Only stop we had was with the clutch where a spring broke and, even if the clutch still was working, we had to fix (easily and quickly) for good functioning. The spring system is actually the old clutch system and today the new clutch does not have springs any more as to avoid them braking.

Also rear braking pads had to be changed. No malfunctioning, just simple wear, that impacts much more rear brake of course, then front brakes, which are used  less and are also double.

October to November – 13 hours, clutch pads worn.

Clutch wear problems occurred. This also happened because a difficulty we had once starting the kart because the battery was low. This led to a heating of the clutch and a deterioration of the pads with subsequent fast wear. A fast and easy change solved the problem.

December – 15 hours, carburetion to be adjusted. Rear brake pads worn.

In a freezing Winter day, with temperature between 1 and 5 °C we decided to go testing and try some new LeCont tires, recently tested with good results at the group WSK testing with many of the major International brands, such as Tony, Birel, CRG, Kosmic, at La Conca track in Italy, after the Nations Cup Final. The new tires built with new oils much “greener” then the previous as for new International regulations. In the specific day LeCont had good performance (not best of all, but good), and where appreciated mostly because of the constant behavior lap after lap.

So we were ready for deep testing of the tires, but after about 10 laps we had the feeling the engine was not performing as well as usually and we decided to stop and open the engine cylinder…for the first time!!! We found a “suffering” piston with worn crown probably derived from very poor carburetion determined by the freezing weather conditions. As we know the colder the weather the riches the carburetion must be and vice versa. If we consider we had ran with the same carburetion setup in August in Italy, maybe we had asked too much to the engine. The piston showed the crown was somehow deteriorating, loosing bits as if it was crumbling down. This effect is determined by detonation generated by poor carburetion. When fuel/air mixture is poor the combustion is not uniform and small explosions are generated in the combustion chamber, especially in the areas further away from the spark plug where combustion starts. This can be easily seen looking at the piston from the top, where a light colored crown can be seen, indicating very high temperatures and detonation.

On the other hand cylinder head was in perfect conditions showing the engine works fine and is never challenged too much in its base setting. This is also the reason why the engine did not seize. So on one side we understood it was time to stop, on the other we thought that only a good reliable engine as the Rok could go on running without seizure in such conditions and we once more had the feeling that one of the best choices for all who want to start running with a kart and one day also try racing, is surely to go for the Rok.