NEWS–September2015Number 25
All About Tyro Racing
With so many new drivers joining us, perhaps we should spend a little time in this News to provide them with useful information about their kart.
Fuel
The Tyro runs on a mixture of 4% good quality racing 2 stroke fluid (Silcolene Pro KR2),and standard unleaded petrol. There is no advantage using the better quality petrol, as only an illegal modification to the head volume would make this beneficial. An easy measurement is 200ml of the racing fluid to 5 litres of petrol. Each time you take fuel from your carrying can you should give the mixture a good shake, to ensure you are pouring the correct mixture. Older fluid tended to separate, but we still carry out this action for safety sake! Always filter the fuel into the kart petrol tank, dirt is our enemy!
Tyres
The HDD tyre will last about 20 race meetings, and it tends to get quicker as the tread wears down. Most people run between 16psi and 24psi in dry conditions. The harder the tyre the more it heats up its surface, but using the higher settings in very hot conditions, the tread may overheat, and the kart will slow. Tyre pressure effects the wall of the tyre, the harder the tyre the stiffer the wall, and more energy is put into the tyre surface. A softer tyre flexes and this places less energy into its surface. However, the correct tyre pressure for the weather and track conditions will give more performance. Taking lap times, you will see the speed increase lap by lap; until the heat generated means the optimum pressure is reached. The perfect distance in a race is for this to happen about 40% into the race but too early and the tyre may go off.
The Tyro Tyre rule - New Tyres may not be fitted at a meeting, unless they were ordered prior to the race meeting. Ordering in advance, and having the tyres changed prior to going out on to the circuit for the first time is fine, ordering in advance, and then deciding you do not wish to change the tyres, goes against the spirit of the regulation and will not be allowed. To recap, the spirit of the regulation is to ensure that the actual weather conditions on day one of a race weekend do not influence which tyres a competitor wishes to use.
Handling
The chassis is your suspension, and its setting will effect the tyres, the lap times, and the way the driver feels about the kart. Standard settings are two 1cm spacers on the inside of the front hubs, and 2cms in from the safety clip on the rear hubs. In torrential rain some drivers prefer to have the rear hubs as far in as they will go (reducing over steer), and the front hubs fully out (increasing under steer). This combination causing the kart to go into a 4-wheel drift rather than have “terminal” over steer.
In order for the handling to be predictable, the driver must sit still in the seat, no leaning over; a moving driver changes the handling and may confuse any handling problems.
The Engine
Capable of running for up to 50 hours, this may be judged as about 90 minutes per race weekend. Some drivers have a check on their engine between 22 and 30 hours just in case there are any problems looming; we have not seen any so far in the 2½ years we have been running.
The Chain
The chain should be lightly lubricated with a high quality chain lube, every other run. Not a bad idea to lubricate the chain when you take the kart home, it gives time for the lube to set on the surface. Check the inner surfaces for cracks, the rollers are the most vulnerable part.
The Carburettor
The most powerful performance influence comes from the carburettor adjustment. On the side of the carb are two adjustable jets, one for low revs, and one for high revs. The standard settings are L 130 minutes and H 35 to 37 minutes, set by gently screwing the jets fully in, and then out again BEYOND the setting position, and then screwing back in slightly. The reason for this is that some of the springs pull the jet to another position, but the over turn and turn back, usually overcomes this problem. The L adjustment is quite coarse so steps ±5 to 10 minutes are suitable. ALWAYS richen a jet first when experimenting, only go weaker (screwing in) when you have proven richening spoilt the performance further. However, the H jet is very sensitive and only 1 to 2 minute steps should be used. There is a small filter in the carburettor, which needs checking from time to time, Steve will be able to demonstrate this for you.
How do you know what is happening on the circuit? When the Low jet is too weak the kart does not pull away from the grid very easily. Other indications of the Low jet being the problem are (1) pulls sluggishly out of slow corners - Low jet too rich OR (2) pulls well but then hesitates out of slow corners - Low too weak. Another guide to the Low jet is a fall off in performance just before the Rissington start line; again try rich before weakening! The high jet will cause the engine to hesitate at the highest revs, at the second bendafter the start, or just before the Dog Leg at Rissington; which way to go is more difficult as too rich or too weak show as similar problems. Always take the rich option first to avoid damaging the engine!
With such a short time at Fulbeck we have not yet achieved the same level of knowledge on adjustment indicators, but we do believe a High jet turned in by a minute or two is a more optimal setting compared with the Rissington settings.
The Battery/Starter
It is important to look after the battery as they are an expensive item! Charge your battery on the Friday before a meeting. Keep an eye on it as it usually only needs about 3 hours of charge, how long a charge takes is an indicator of battery condition, a good battery holds its charge and does not need so long to fully charge. There is a 40amp fuse inside the battery as a safety device, although they do not seem to be available in the UK (Protrain have some).
The Drivers Clothing
Modern helmets are made for children, and are called CMR helmets; compulsory in MSA racing. A helmet should try to pull the driver’s ears off when it is being removed! A suit has, on the back of the collar, the date range for that particular homologation. Each homologation lasts for 3 years, but these figures do not effect the validation of the suit; in the UK the suit must be produced after 1999, earlier suits are now illegal.
Spare Parts
We carry an almost complete range of spare parts for the chassis and the engine. We also include 2 stroke mixture, chain lube, bodywork cleaners, carb and brake cleaners in our box at each meeting. Always ask us first if you need anything, as we will often have what you want.
Rissington August Round One 8-9-10
Not the most attended of Tyro race meetings, August was in the past the month when race meetings just did not happen as the numbers were too low; we kind of proved why! Numbers were well down but entertainment was certainly still high on the list. Extra drivers were with us for Saturday, including Thomas Barlow, the winner of our latest competition for a "taster day".
Heat one was led away by Livi Holt, who was to suffer through the day with brand new tyres overheating. Very rapidly Robbie Sims came through from grid four, taking the lead and holding it to the end. Livi and Charlie Thompson battled away with Jed Brown chasing them to the flag, but Charlie stealing second with two laps to go. New boy Lewis Jones ran round at the back, his first ever race day at Rissi. The result Robbie (49.99secs) first from Charlie (50.27), Livi (50.37), Jed (50.56) and Lewis (51.27)
Heat two and it was Charlie leading this time, chased by Robbie and Livi. Jed and Lewis not to far apart infourth and fifth. Just one major overtake in the race took place on lap four, when Robbie took the lead. At the flag it was Robbie (49.89secs) Charlie (49.90), Livi (50.04), Jed (50.67) and Lewis (50.61).
Heat three and it was once again Robbie rushing off into the lead with Charlie chasing him. Livi back in third only 3 seconds behind at the flag. The track rubbering in was great for the first two, but with new tyres it put Livi in more trouble.But observers could not be complacent as the first two towed each other round, but a last lap dive from Charlie at the Elbow gave him clever victory. The result Charlie (49.62), from Robbie (49.72), Livi (50.13), Jed (50.18) and Lewis (50.25) improving his times lap by lap.
The final commenced by Charlie jumping ahead at the start, but before the lap was complete Robbie had taken the lead. Behind them, holding their grid positions, were Livi, much quicker with lower tyre pressures, and Jed, but after holding on to Jed for a good number of laps, Lewis lost ten seconds with a couple of spins. The front two always so close together, would they touch, could they keep this pace up? Then, on lap eight, Charlie took the lead! Last lap and yes, Robbie took the lead back just holding on to the flag; Charlie 0.9 of a second behind; great racing by both of them! Our final winner Robbie (49.59secs), from a brilliant second,Charlie (49.67), Livi (49.79), Jed (50.24)and a exasperated Lewis (50.36)
The Tyro 8-9-10 Racing Raffle Points?
After the above round (Fulbeck cancelled) the points are as follows -
59 - Robbie55 - Charlie48 - Livi42 - Jed36 - Lewis
The proposal is to have 8-9-10 trophies down to fifth place, but a driver must compete in at least 4 of the 6 races to qualify for a trophy.
Remember that we will also be looking at driver conduct in relation to points accumulated in the raffle; additional pressure to keep you to the Tyro driving ethic.
Still Great Deals On Gillard Suits
Tim Gillard is still offering first quality race suits at £150 plus VAT, a steal at nearly half price!
How Are You Doing?
In numerical order, just how "regular driver's" lap times are changing 2013/2014/2015, remember only race laps count?
14 Oscar - 00/52.51/50.3015 Lewis - 00/00/50.2516 Livi - 50.98/49.81/48.90
18 Val - 50.25/49.89/49.60 28 Georgie - 49.69/48.87/49.0733 Robbie - 50.27/48.80/49.01
56 Charlie - 49.46/48.81/48.88 90 Archie - 00/00/50.15
91 Guy - 00/00/49.3594 James - 00/00/50.2398 Jed - 00/51.18/50.38
Steve
07711606967