It’s a matter of gravitas that has occupied the minds of many Cadets and their parents over the years. I’m talking here about the weight differentials between young drivers and their ultimate effect on speed. It’s never been a problem for individuals such as Ollie Walker and Bill Cowley who both had their karts well weighted up before moving out of the class. Others, such as Billy Baxter and Ben Walker, were tipping the scales with several kilos to spare even when they had two or three years left as Cadets. John Mills has calculated that in dry conditions, an extra kilo of weight accounts for around one tenth of a second on lap times. This calculation proved to be accurate enough during recent tests at P.F. carried out under ABkC observation. Running at 93kg Sam Clarence was exactly 0.7s quicker than his best time when weighted up to 100kg. The lower weight limit of 93kg was introduced by JM in an attempt to maintain the competitiveness of WTP pull start engines now that a new and more powerful TAG version has been adopted. Unfortunately, this is no help at all to those who have been struggling to make the old weight limit. There is a certain amount of variation in chassis weight but, if we take a Zip kart, fully fuelled, as an example, then a driver weighing 38.5kg will just about make the 93kg limit. This is considerably lighter than his counterpart on a Comer W60 who can afford to reach 43.6kg.
However, a Honda Cadet would need to be lighter still at 36.9kg. Those on WTP TAG engines could tip the scales at 44kg and still be underweight. Allowing for lightweight parts, lower fuel loadings and the fact that many competitors allow a safety margin of more than a kilo, John Mills believes that well over 50% of Cadets fit comfortably into the 93kg bracket. Having looked around the paddock at many events last year, I wouldn’t disagree with this assessment. Although competitors can afford to be several kilos overweight before their performance is affected, there’s one area where just a few grams can be of critical importance. Many WTP owners have complained about a lack of power when the real problem has turned out to be a faulty exhaust. “What goes into an engine and what comes out are the two biggest influences on power output,” explains John Mills. “People tend to spend lots of time ensuring that the carburettor is properly set up but neglect the exhaust. Consequently, they eventually suffer from lots of carbon build up and there is a significant power loss. The way to anticipate this situation before it shows up in poor race results is to weigh the exhaust. A brand new one weighs 2250 grams. Once in use there will be an increase in weight from oil deposits. The optimum weight then becomes around 2280 grams. Any exhaust weighing more than 2.3kg will adversely affect performance. Buying a new exhaust is one answer but soaking overnight in a solution of caustic soda should produce the right results.” Jordan Barnes is an 11 year old competitor who has been giving the matter of weight some thought over recent months.
Despite keeping very fit on his mountain bike, Jordan realised that he would be at a disadvantage when the new weight limits for pull start motors take effect. Consequently, his father recently invested in a brand new electric start engine and the sudden power increase has certainly impressed him. Jordan is a keen F1 fan and names Kimi Raikkonen as his favourite driver. Not surprisingly, McLaren-Mercedes is his nomination for top team. In karting, he claims that Aaron Mansergh is the driver he most admires. Jordan started karting in May 2004 and passed his ARKS test at the Rowrah Bank Holiday event that same year. After losing his novice plates in February he started to achieve some very good results, particularly at Rowrah, and finished last season as the NKF champion in Cadets. His ambition this year is to do well in the Little Green Man championships. “I think the NKF last year was a very good series although we were a bit disappointed with the coverage it got in Karting magazine,” says Jordan’s father, Martyn. “It certainly encouraged us to visit other circuits and there was a friendly atmosphere at each round. Jordan was thrilled to attend the prize presentation to receive his championship trophy and it was a very nice touch staging this at the Donington Kart Show. I’ve seen how the Little Green Man series is packaged and I think that Mike Mills does a superb job in making all the competitors feel important. Also, having a pool of motors available for hire is a big advantage as it means we’ll be able to compete with just the one engine. We’re definitely looking forward to taking part and if Jordan can get a few good results then so much the better.” Apart from attracting the established names in Cadets, it’s important that the Little Green Man also appeals to drivers such as Jordan Barnes. I hope that he has lots of success in 2006.