This setup guide is here to assist you in achieving the best results possible. Kart preparation in any form of motorsport is KEY but in F400 it’s even more vital as endurance racing takes it toll on even the most well prepared kart.
Just a comparison:
One F400 Race day is the equivalent to Four National 2-stroke Events which is in the region of 400 laps, one 2-stroke race with unofficial practice, official practice, qualifying, heats 1 to 3 plus maybe even a final is no more than 100 laps.
The biggest differences between 2 stroke and F400 karting are in order of importance:
So what’s the Magic Key to prepare your kart for a F400 or F200 Race Event?
1. Check that all the nuts and bolts are tight (Don’t use old nuts and bolts)
2. Change the nuts and bolts at least once a year (Every season)
3. Brake Fluid: re-bleed the brakes every four events (Fill the brake master cylinder after every 2 races)
4. Brake pads, if the pads have less than ¼ pads left, chances are you going to run out of brakes
5.Make sure that the travel between the pads and the disk isn’t too much or your pedal could became long (Which is the brake fluid overheating)
6. Use a Dot 4 or Dot 5.1 brake fluid (never mix with dot 5, which is silicone based)
7. Harder brake pads are a better option when replacing your brake pads. Remember 2-stroke pads are designed for short 2-stroke races and are generally softer material.
8. Bearings. Please check the bearings on the kart, wheel bearings, axle bearings, rose-joints. After a race weekend you can spray some 20W40 if the bearings are older to keep them loose. If your bearings are worn you have zero chance of winning as this could cost you anything from 0.2 tenths a lap to 2 seconds or more depending on what bearing it is.
9. Chassis. First and foremost have the chassis checked that it is straight, it will go out slightly with every race. Trying to turn a kart with a slightly bent chassis will lose you anything from 0.5 seconds (If you lucky) to 2 to 5 seconds a lap. Paying a reputable workshop to get your chassis straight and wheels aligned is worth every cent.
10. Axle, make sure the grub screws on the axle bearings are tight.
11. Make sure the engine mounts are tight and the chain has 8mm to 12mm of play, no more no less.
12. Replace the accelerator cable every four to six races, make sure the accelerator pedal has a stopper so you set the accelerator pedal to stop when you have full throttle. If you don’t do this you will break the accelerator cables or damage the carb where the accelerator is attached.
13. Fuel Hose, check and replace from time to time as fuel causes the hose to get hard and brittle over time (Especially the piece inside the tank) (Also have a fuel filter and replace every 6 months to 12 months) If you getting air in your fuel line its usually the pickup in the tank.
14. Engine oil, the Honda 390 engine in race trim should use fully synthetic oil (Shell 5W40 is as good as gets) as it works better with the heat and higher revs. Synthetic is moderately thinner oil compared to multi-grade. Don’t start your engine and rev it unless you looking at purchasing a new one. The engine can be over-revved on the stand causing terminal failure. (Penalty for over-revving an engine on the stand – replace engine with new one)
15. Make sure your front spoilers, side pods and rear bumper are secured properly
16. Your weigh brackets must be connected to the chassis in three different points, brackets supports must be at of the flat bar type, minimum of 3mm thick and at least 3cm wide. The 3 points are usually the seat, the chassis (where the 2 strokes connect the radiator) an the rear bearing.
Let’s start with the basic F400 Setup:
Have your seat setup between 104cm and 105cm, from the top of the left kingpin bolt (That’s the one that holds the stub axle in place) to the top centre of the seat. Any variances from this could cause a loss of rear or front end grip. The back angle of the seat can be anywhere between 20cm and 25cm from the axle to the top of the seat – chassis dependent and personal comfort as you don’t want to be sitting straight up racing for 2 hours) (My kart is set at 21cm from the top of the axle to the top of the seat)
Note: A seat can be set with the bolts not 100% tight allowing additional flex in the chassis, I prefer using rubbers between the seats (Allows flex) and big washers against the fibreglass which increases the strength of the seat as the washer sits against the fibre glass. (You can also use aluminum plates as this makes the surface area bigger (Tighten bolts around 90 to 95% tight thus allowing flex. (To much flex can also cause the seat to take strain and break, over-tightening the bolts can do the same as the fibreglass will start cracking because it needs moderate flex)
If you have weights try moving them around the kart to get the best possible weight distribution on the chassis. Remember you can only add permanent weights if your heaviest driver is underweight)
Rear track width: Always measure from the outside of each rim (Take the tape measure and put it through the centre of the axle, have a ruler and attach the tape measure to the ruler having the ruler against the outside of the rim. (This distance should be 138cm) Make sure your axle is centred in the chassis, measure the distance from the end of the axle to the bearing. For more flex have the axle bearing facing inside (The grub screw will be on the inside facing the brake disk, both sides must be done the same) Remember that by going in on your track width you can get more grip but too far and you can lose grip, axle hardness can affect grip/flex. Rear hub lengths can also affect grip, short hubs give less grip but more flex, medium more grip less flex, long hubs even more grip and yes less axle flex. Don’t think by just adding a longer hub that your karts rear grip will just improve as many drivers will say the back is loose when in fact the back end washes which means it lets go on the exit of the corner. What could be happening is that the front has too much grip (too wide) and the back cannot cope. If the seat is setup at 138cm than I would suggest you first adjust front end grip before fiddling with the rear. (You cannot have the rear wheels wider than 140cm) A rule of thumb when it comes to the rear end sliding is if its only happening on fast corners and or fast chicanes, the front end has too much grip (too wide). Also changes on the rear of the kart are usually to fix problems with corner exit. If you are having handling problems on corner entry then the problem usually lies with the front of the kart.
Middle bearing can be run loose, allowing additional flex (We use a cable tie which allows it to move ever so slightly yet stops rattling)
The height of the axle can change handling characteristics of the chassis (Having the rear axle in the lowest position raises the chassis, raised chassis with hard tires allows flex and better driveability) There is an added bonus (The seat shouldn’t hit anywhere if you go onto the rumble strips) Additional Height on the front end of the kart does assist the kart on turn-in; you would have to move spaces between the stub axle and chassis to adjust height. Move stub axle lower to lift chassis ride height.
By adding rubbers to the floor-tray it helps additional flex on the front of the kart which can add grip, too much front end grip than tighten your floor-tray and front end. Bars that the front spoiler attaches to.
Running a kart with slick tires (No wets allowed) on a wet track is a fine art and needs lots of practice. Most teams don’t make adjustments but if the rain is going to stay then you can increase tire pressure all round. Go as hard as you feel comfortable 1.9 – 2.2 Bar (Harder than that is likely to have no additional effect) On the front you can add additional toe out (Normal dry is 1mm) Go maximum 3mm to 4mm, sounds stupid but it adds grip.
On the rear you can move the rear wheels in from say your 138mm to 136mm (If the wheels can go in that far because of the engine)
You can also add long rear hubs to the rear which will add grip, remember if you get too much grip at the rear your kart will push in the front (No turn in) In the rain it already pushes as slick tires and water don’t seem to agree with one another let alone add the fuel-oil that has now been put on the track from all the previous races.
It’s extremely difficult to give a perfect setting because chassis differ Start with going as wide as possible and then adjust the spacers and move the wheels in slowly, when the wheels are at their widest setting you will have less front end grip. But if they too far in than you possibly could have too much front end and no rear end grip.
To also create additional front end grip, add more caster which makes the steering heavier but loads the front wheels more on turn in. If you have too much front in grip rather back off some caster before moving the wheels out as that will make the kart easier to drive.
Steering Arms, on some stub axles you can have two or three holes where you can attach the rose-joints. Inner setting will make your steering wheel more sensitive (Sharper turn in with less turn on the steering wheel) Visa versa as you go out. I personally favour the middle setting as it allows moderate steering turn in which is not over sensitive and allows the kart to flow into the turns.
This can be adjusted to what suits your requirements. My previous chassis manufacturer recommended 0 degrees camber and 0 degrees toe. This will automatically go into a negative camber as soon as you put the kart on the ground let alone add a driver.
Negative setups like 2-strokes karts will increase turn in but will have a negative effect on tire life and based on a maximum of 5 sets per team you may want to look after your tires.
Recommended setting, Camber 1mm to 3mm Positive Camber / 1 to 2mm toe out (mm are measure on an alignment gauge)
Again I cannot tell you the perfect tire pressure for your kart, adjustments of tire pressures can increase grip levels. The lower the pressure the longer the kart takes to heat up the tires (Heat in the tires gives grip)
Start with 1.7 bar all round and adjust the pressures to what the kart is doing on the track. I personally won’t run my front tires harder then 1.7 bar, rear tires I have raced up to 1.9 bars. (Suggested race pressure between 1.4 and 1.6 bar all round)
The pressure ranges suggested by Dunlop are from 1.2bar to 2bar. In wet races you can go up in pressures which will lift your chassis ever so slightly.
The sidewalls on Dunlop SL1 Tires are the same both sides so the tires don’t have a specific Direction.
Racing Lines and how to drive a kart faster
Let’s be honest everyone would love to drive a little faster and in 4-stroke racing the neater you drive a kart the faster you go.
As an Example let’s start with a simple left hand corner, when you approaching the left hand corner you need to be as far over to the right hand side as possible (visa versa for right hand corners). This allows you to turn the steering wheel less but allowing you to carry more speed out of the corner.
Also you need to imagine your kart has a trailer behind it so don’t turn in to early as that will push the front of the kart out wide midway in the corner and your imaginary trailer will land up hitting the curbs.
When do you start braking?
Well that will depend on chassis setup, front turn-in and rear grip and the driver but the age old saying is slow in fast out. The reason for this is if you brake early you can get on the power earlier as you not carrying too much speed into a corner (To much speed will mean the kart will understeer meaning it won’t have enough front grip)
Also by going too fast when the front does grip it could cause oversteer which means the back will start sliding. On a 4-stroke kart the more you slide your kart the slower the laptime? Does look like you driving fast but you not.
Understanding a corner and what follows thereafter
Remember when you racing some tracks have a sequence of corners which can compromise how you take the first corner to get through the second corner)
As an example Vereeniging after the tower in an anti-clockwise direction (After the Long left hand sweep) there is a sharp left then around 15 metres later a double right.
If you take the perfect race line for the first left (This will cause you to run deep toward the curb / rumble strip) then your line for the first of the double right hand corners will be compromised as you will have to turn the steering wheel sharper which could cause the rear end to start sliding. (That is if your front end has the grip to turn) (Remember this sharp turn will also cause your imaginary trailer to hit the inside curb thus proving your line was incorrect)
This will make for an untidy entry of both right handers and could lose you anywhere from half a second to over a second. (Not so good)
I say it will compromise both the following two corners as your kart will be upset (Not smooth as you will be bouncing over curbs) thus affecting your rhythm and yes the following corner 50 meters down the road could be compromised as you are now upset with yourself. So many times I’ve seen drivers make a mistake in one corner and for the rest of the lap he/she drivers like a baboon (That’s a nice way of saying it)
The optimal racing line in this case is to slow down and be able to miss the curb by around half a metre to one metre (Depending on the chassis setup and how it can cope with the following right hand) then move as far over to the left which will allow you to aim as close to the curb on the right hand corner which will allow you to turn and carry all the momentum into the second of the right hand corners.
The braking on the first left is so critical that if done correctly will mean no brakes will be needed for the following two right hand turns and you won’t be fighting the kart through any of the three corners, you will be driving the kart. (Karts don’t go their fastest when ill-treated)
Let’s also explain something with fighting the kart
Some people might be able to drive fast with locking brakes and in an untidy manner which holds more risk of mistakes than a neat driver. So yes you benefit from one, the risk factor but even better someone trying to thrash a kart around a track will work so much harder and believe me will make a mistake because he/she gets tired and loses concentration. Untidy drivers do get (karma) paying them back and over twenty to thirty laps will make at least five times the mistakes of a driver who drives on the limit and not over it.
Let’s just assume that each mistake is only punished by losing one second here and there (So five mistakes versus a good drivers one mistake, that’s four seconds over 30 laps as we deducted one second for the mistake the good driver made) Then look at the picture below and I can tell you I finished second in this race by less than half a second. Four seconds could cost you several positions and could cause your other drivers to try catch up that time which could cause other issues. (One been crashed up kart)
When testing have an idea of what you going to do
Don’t go and drive for the sake of driving. If you a new driver yes time in the kart is a brilliant idea but use that time to explore different lines on the track so you do get an understanding of how to approach each corner better. (Don’t fiddle with setups as you won’t know what’s better if you driving incorrectly)
Don’t start pushing for laptimes; this will cause you to lose focus on how you approach a corner. Approaching a corner correctly is far easier to do when you driving slower rather than faster so learn to take the corners correctly and I will guarantee that when you start pushing the kart for ultimate pace you will find it easier and it will become natural to you so new tracks will also be easier when learning them.
By learning how to approach corners correctly and not overdriving them you will also benefit from not spinning the kart thus will help with not damaging the chassis or bending axles as other drivers don’t expect you to spin. (So don’t blame them for crashing into you)
Be predictable on the racetrack; don’t weave on the track
Knowing there’s a kart behind you without looking should become second nature. But as a starting point try learning when you enter a straight to have a quick look back (Just don’t turn the steering wheel while looking back) and make sure there’s no slow moving karts in front of you, thus can be done by planning one lap ahead so you already know what’s in front of you. Some tracks allow you to see karts catching you as you can see them when you’ve turned as you can now just take a quick look to your left or right depending on the track.
Expect the unexpected at all times
When racing against other karts always expect the unexpected. (Plan for the unexpected) As an example you have just been overtaken by a faster driver, you are approaching a corner and he is one to two kart lengths in front of you. Expect him to lock his brakes going into a corner (2-stroke driving style) even worse expect him to spin and have a plan ahead on how you going to avoid him. This is what makes top drivers different as they can get a feel of karts and the better drivers will rather lose two seconds then have their kart crashed out.
What to do if your kart breaks down
Move the kart away from the racing line as quickly as possible as someone following another kart closely may not be able to see you. If the approaching corner is a right hander move the kart as far over to the right as possible. If you’ve spun in the middle of the corner move the kart away as far away from the optimal racing line as possible. (Imagine a kart is approaching too fast where will he/she land up spinning?) Make sure your kart is nowhere near that point.
How many times have I seen drivers leaving their karts in the line of fire? I don’t have enough fingers or toes to count and yes someone can crash into a kart that’s broken down and get hurt.
I did crash into a kart that had broken down (Think 2004 or 2005) because I entered the main straight (Zwartkops) following another kart and didn’t see anything in-front of me that shouldn’t cause any problems and was on the racing line, I looked back to check something on the engine and a team had pushed their kart which had broken down back onto the track onto the racing line midway down the straight (Must have been doing 70km/h) (The other driver went past the kart as he had seen it but my vision was blocked by the kart in-front of me.
When I looked up I swerved as there was suddenly a kart in-front of me that had a driver in it which was stopped. I hit the kart with the right hand side of my kart bending the axle and breaking the rim. (That was a lucky escape) I have thought that if I didn’t see him when I did I could’ve hit him straight on at 60 to 70km/h, that would have most likely crushed both feet and legs not to mention what the steering wheel would have done to my chest not to mention what damage my kart would have done to the driver sitting in the other kart (Maybe a broken back)
This isn’t intended in scaring you from racing but if you are careful and responsible look out for your own safety and that of other drivers.
The safety of everyone that races in F400 Racing is not just the responsibility of the Marshalls, COC, Technical Committee or scrutineers but every single driver that races in F400 Racing.
We have had karts that have flipped over and yes drivers who have broken their collarbone but let’s get real this is motorsport and in 14 years a broken collarbone or broken rib is not bad considering all the racing laps we’ve done.
I also do suggest that every driver races with a rib protector as it helps the back and stomach muscles with support and can also add the added protection in an accident.
Let’s keep it safe in F400 and have no unnecessary incidents
Good luck to all those all entering the championship and I hope the above information helps in preparing a fast, reliable kart and assists you in driving better, faster and safer.