Written By: Grahame Butterworth
Spring is sprung – at last! Suddenly lots is happening on the TKM front around the UK. So let’s catch up on the news on and off the track.
First let’s just make the point that TKM numbers have been rocketing especially in the midlands area where at circuits like Kimbolton, Shenington, Rissington, etc the Junior TKM grid is the largest of the meeting and the seniors are not too far behind. No less than 45 Junior TKMs at the last Kimbolton meeting.
And it is good to hear that other circuits like Rye House for example are working hard to rebuild their TKM grids. The TKM class is very definitely growing once more, with increasingly Cadets (and their parents) recognising that the step into Junior TKM is the logical one to make for a variety of reasons.
Partly to help these potential newcomers and of course to help those in the TKM classes at present, there is a unique test day being held exclusively for TKMs at Whilton Mill on Friday July 26.
The circuit will be available to any TKM driver – including those without an MSA licence – to test for the day from 10am till 4pm. A full day there normally costs £50 but on this occasion it will be just £30 per kart.
There will be sessions split for Juniors and Seniors – and a further session for newcomers taking their first steps in a TKM kart. Top traders operating in Formula TKM will be there with test karts as well as Mr TKM himself, Alan Turney.
This is the perfect opportunity for drivers to find the sweet spots at this excellent circuit which now has a number of changes to barriers and kerbing as part of a substantial upgrade program promised by the owners.
If you’d like to take part in the TKM test day please email firstname.lastname@example.org It has been timed to fall just at the start of the schools hols so a good way to kick off the summer!
What’s more that test day is ideally placed to help drivers taking part in the TKM Club Championship which gets underway just as this magazine comes out with the first round at Kimbolton and with whopping grids. The final round double header at Whilton Mill will be a great finale.
And still on Kimbolton, a reminder that of course the Maxxis TKM Festival takes place there as ever in mid August and looks like it will also have some very strong grids. Full details of regs will be announced shortly but expect it to be very much in the tradition of this top event in the TKM calendar. August 10/11 is the date for your diary.
OK so enough of the off track diary stuff and now let’s move back to the track and reflect on the fact that the weather has finally changed – I hope!
Change in temperature really does make quite a difference to the way you go about running a TKM kart – or any other come to that. Now if you have been around in the class for a while then you’ll know what to do I hope, but for the benefit especially of newcomers who have joined this year and raced only in icy conditions, let’s go through the key points.
Engine wise you will almost certainly need to change the jet settings. The TKM BT82 likes to run at low engine temperatures and as the ambient temperature rises then it will need a little more fuel going through to keep it at top performance.
So look to slightly open out the high jet and keep looking for a puff of smoke from the exhaust when the driver puts the power on out of a slow corner. If it is doing that after a few laps then you know it is about right. Loads of smoke means it is too rich and none that it is too weak and engine will get hot and run slow after 4-5 laps.
Remember the piston port nature of the TKM engine means it will not seize like a Cadet if slightly too weak, but it will lose performance. It likes to be run rich for best performance. You can check the colour of the inside of the exhaust bend manifold after a race for guidance on how the engine has been running. Simply slide off the exhaust pipe with flex and look for a black to brown colour for good carburation. If light brown to grey-white then you are running far too lean and will be losing power.
From a tyre point of view then some big changes may be needed. The slicks ideally run on 130mm width rims at the front and 210mm at the rear and at pressures of around the 10 – 12 psi mark. It may well be that in the cold weather narrower rims and significantly higher pressures have been needed to get some heat into the tyres.
So now we are out of the ice age look at completely re-thinking strategy on that front and experiment to find what best suits your kart and driver. Before you start playing with the track adjustments optimise the tyres and then fine tune for best lap times and handling.
As far as the wets go now the weather has perked up suddenly those that said the new wets were half a year slower are now recognising that with some track temperature they come alive and are significantly quicker.
Again you may well find that instead of maybe 120mm and 150mm rims with high pressures you need to switch to something like 130mm and 180mm to really make the tyres shift the water and perform at the best. Certainly drop the pressures down to more like 12 – 16 psi.
The driver – well he can finally take off thermal underwear and two pairs of mittens! Enjoy.