MAXIMISING PERFORMANCE WHILE SAFEGUARDING THE LIFE OF YOUR TKM BT82 ENGINE
Over the course of the past few years several changes have taken place within the world of fuels and oil which are significant to the performance, and critical to the long life of our engines. We have issued advice on a number of occasions but here we bring together the key points and our best recommendations.
Fuel
All standard unleaded fuel you buy at the pumps in the UK now must have a 10% ethanol content marked E10. It is used for ecological reasons.
But ethanol is less volatile than petrol and reduces performance. More than that ethanol can cause irreparable harm to petrol-fuelled engines, whether in a car, a chain-saw or your kart engine.
There are four main problems with ethanol:
- It is corrosive when in contact with certain materials in fuel storage and delivery systems, including some rubber compounds and the zinc and aluminium alloys used in carburettors.
- Because it is an alcohol, ethanol dries out the rubber components in a fuel system. This can lead to brittle fuel lines and degrade seals and diaphragms.
- Ethanol is hygroscopic – it likes water. Water can enter fuel containers when they are filled up. Once in the petrol, it forms a chemical mix that causes corrosion of internal parts. As the fuel level in a tank or container drops, water condenses on the cool surfaces of the vessel, drops, and runs down into the fuel where the ethanol welcomes it.
- Within 2-strokes, the ethanol solvent cleaning effect is a serious problem because it can reduce lubrication – vital to the life of your engine.
For this reason, we now recommend the use of Super Unleaded 97/99 octane fuel which still has only a 5% ethanol content marked as E5. And we are pleased to now confirm that the control fuel used at all British Championship rounds is a special blend with approximately 3% ethanol.
Our key advice here is that whichever fuel you are using you should always add a minimum of 320 ml of oil to 5 litres of fuel. We know that some drivers/teams use less oil in a search for greater performance but we must underline using less than 320ml per 5 litres may potentially cause serious engine failure especially with the higher ethanol E10 fuel.
Oils
For years we have recommended the use of Shell M castor-based oil for our engines. It gives excellent performance and long life. So, when Shell withdrew it from the market we were very disappointed as were many users world-wide. We have not rushed to advise on a suitable alternative because we needed to see how products performed.
It is our observation that there is no oil available which is an exact copy of Shell M. However, we see excellent results from several quality castor-based oils which also contain an amount of synthetic content to help offset the ethanol.
These are:
Elf HTX 909
Fuchs Silkolene Pro KR2
Vroom Factory Racing 2T
Ravenol Racing Castor 2T
In each and every case we still underline the need to use a minimum of 320ml per 5 litres. We will add to this list if we see good results from other oils.
Carburation
Closely linked with lubrication comes carburation. Our running guide, which is freely available on our website,
https://www.tal-ko.com/PDF/TKMBT822STROKEINSTALLATION&RUNNINGGUIDE2021.pdf
gives our recommended starting point on settings. The critical factor is to ensure that your engine is getting a rich mixture. Unlike other types of 2-strokes which require the mixture to be ultra-weak to gain performance, our engine is the opposite. A rich mixture will give superior power as well as longer engine life because of greater lubrication and cooler engine temps. It will also improve mid to higher rev range power.
Make no mistake, setting the mixture too weak will cause engine failure.
Engine Revs
Our recommended maximum continuous revs is set at 15,000 rpm with the proviso that up to 15,750rpm may be used for the short bursts sometimes required for circuits. And our running guide also stresses than while the engine will very easily pull well over 16,000 rpm, such usage will dramatically reduce its life and can potentially lead to a major failure.
We know some drivers boast their engine will reach 16,500rpm and more – but we stress that such use is well outside the parameters we set for the engine. It is also highly likely that taking off teeth and tuning for lower maximum revs will actually give more speed.
So we underline use of the engine over 15,750rpm will reduce its life.
Balance & Engine Condition
Vibration is something that occurs in all engines and can be destructive. On a race engine running at 15,000rpm and more, it is important that everything is in good order. If an engine is slightly out of balance because the crank alignment is out due to a lost chain then it can put extra strain on the rotating parts.
Equally excessive bore wear and alignment or wear in components and any imperfections in build can also have a damaging effect.
So we push hard the message that using the correct amount of top quality oil, keeping the revs under control and ensuring the engine is in good shape will give you best performance and engine life.
