By: George Robinson
The MAX Column has been running for four and a half years. During that time much has changed and a lot of MAX engines have been sold to every kind of customer. The British Isles remain firmly at the top of world sales along with France and Australia. Over 5,000 engines have been sold to date in the JAG distribution area of Britain and Ireland. Of these approximately 3,500 are Senior engines and the balance is Junior. JAG was the first distributor to introduce sealing and the system has been highly successful, so much so that Rotax have adopted the same type of seals and supply them to their distributors all over the world. Every engine that comes into this country is fiche checked and all the records are kept on file for future reference. John Gravett, who put the ‘G’ into JAG, personally checks every single engine and so has a very good handle on the consistency of the product as it lands here from the factory. I know that now, after almost six years of Rotax MAX, there are rumours of complacency.
Nothing could be further from the truth, in fact the standards of engine service and maintenance have continued to improve since the agents were accepted and the majority have had an audit visit. The purpose of this is to ensure that the dealers have adequate equipment to carry out rebuilds to a quality standard that will prolong the life of reworked engines and at a consistent level of performance. There are now in excess of forty approved service agents and they have all agreed to rebuild engines within the bounds of the official fiche and stand the ultimate risk of being struck off should they fail to do so. Provided that they have made the necessary investment in measuring equipment then the fiche checks are relatively straightforward. Sealing agents having made their commitment to the servicing of Rotax engines do deserve the reward of a consistent number of rebuilds coming their way. The current feeling seems to be about twenty to thirty hours for a Senior engine and more than that for Juniors or Minis. In fact I have recently heard of a Minimax that was rebuilt at sixty hours and looked as though it had just been run in.
No doubt the Minimax with its heavily restricted output has a very easy time of it in terms of stress on the 26 internal components, already super reliable in the Senior engine which produces just short of double the horsepower. The new Minimax restrictor is now available. After much testing and discussion to find out what was really required by the MSA and the other powers that be, sanity has finally won through. The new exhaust restrictor has an exit bore diameter of 20.3mm and no inlet restrictor is required. This will benefit the class considerably in that it has a couple of advantages over the old system.
Firstly, by doing away with the inlet restrictor this will greatly reduce the risk of icing in cold or high humidity cold weather. Secondly, I believe the engine will be easier to manage in terms of jetting and the jets are likely to be smaller than we are used to, probably by two or three sizes. The official wording of the new restrictor regulation is “Confirmation Regulation B4.4.2 Restrictors. Exhaust Restrictor Only, No Inlet Restrictor required.
Exhaust restrictor must be in place at all times. Restrictor must be as supplied by JAG and comply with the official fiche, no modifications allowed. Exhaust flange restrictor 20.3mm maximum round bore. All exhaust gases must pass through this restrictor”. That’s it. It’s really very simple to fit, equally easy to police and impossible to modify without risking detection, a win/win situation to further enhance this highly successful class. The carburettor must now be standard in every respect, the only part that may be changed is the main jet.
There is only so much you can do to make a carburettor work properly, so the wild claims about massive power increases should be a thing of the past. The principal causes of carb faults are dirt and incorrect float heights. From now on the Rotax supplied in-line filter is not only allowed but also recommended. This filter should be changed at least every twenty hours but this of course is a general rule and is entirely dependent on the cleanliness of your fuel. The filter is clear material plastic and so should be easy to see through and get an idea about its condition, if in doubt chuck it out and fit a new one. There will some significant changes to the MAX International Challenge format and the finals themselves.
There will be a full series of races for Juniors and Seniors, with at least the best of each winning the dream ticket. At this stage it is anticipated that Juniors will have all their equipment provided for the World Finals. The Seniors, having competed on their home turf on their own MAX equipment, will arrive at the (as yet secret) destination to race the Rotax supplied RM1 karts. Now this I want to see! In countries where there is RM1 racing taking place, I understand that they may also be able to race for a place in the World Finals. Here in the UK there has not as yet been enough interest to run anything more than demonstration races with the RM1, however the news is good because JAG are offering test drives free of charge to interested parties. So far it looks as if there will be at least four venues where anyone with a degree of competence can come and have a go. If you think that might be for you but are unsure whether you have the experience, I can promise you that the RM1 is dead easy to drive and you don’t have to try to break the lap record in your first couple of laps.
JAG also has two Senior MAX test karts which I believe will be made available for the less experienced to acclimatise themselves. This has to be a great opportunity to try something a bit different. For those of you not sure what the RM1 is, it’s an automatic adrenaline machine. It has a two speed gearbox with a steering wheel mounted paddle shift. The engine looks similar to a Rotax MAX but in fact has a slightly uprated cylinder barrel producing around 32 horsepower as opposed to the MAX that gives 28hp. The gearbox is integrated within the engine’s main cases and is directly behind the crankcase. The rear axle passes through these cases and is driven via a spline which has a flexible fixture onto a hub. The kart has a four wheel brake system with self adjusting split hydraulics front and rear that also have a bias control that can be adjusted on the move.
There are many innovative features on the RM1 that make it unique in the world of karting as we know it. If you would like a no obligation test and to have a closer look `hands on’ then please contact J.A.G. on 01892 611805 or by fax on: 01892 611806. Alternatively you can email me at email@example.com At this time of year I know I’m right in saying that for many of us, karting and the thought of getting out into the workshop to do any maintenance come a fairly long way down the list. Unfortunately, without some attention now, our trusty karts will not be so faithful when the first of the spring weather comes. Please, first of all, check that the engine has antifreeze in its coolant then make sure that the fuel is completely drained. Any residue turns to glue and can completely ruin the carburation to the extent that the engine may refuse to start until the carb has had a specialist rebuild. If possible keep the kart somewhere dry and not too cold.
Tyres also benefit from not being left out in the cold. Only you can judge how much of your karting equipment you can cram into the cupboard under the stairs before you yourself get banished to the shed at the bottom of the garden. So far the 2004 season looks really exciting for the Rotax classes and lots of new ideas and opportunities to go racing has to be good for all. I will try to keep the news coming and try to keep it interesting. If anybody has a topic they would like researched, aired or printed please contact me direct at the email address above or via the magazine.