French KFS IAME 100cc kart restoration project

bobakartdad · May 17, 2025, 5:48am

I’m new here on the forum so let me introduce myself: Middle aged, engineer, restoring an old french sportscar working with IT quality, helping my 25 yr son get into karting with almost no budget, northern Europe. We’re trying to get an old Birel/Vortex Rok kart which he bought last year run, but this thread is about restoring another, partially complete kart he got a few months ago: A KFS IAME 100cc. It was imported here at some point from France, with little meaning, as nobody are running the KFS karts outside of France. So we started researching what we could do with it

The bad stuff first:

Chassis has many rust stains
Rear axle completely brown from rust
Chromed parts all stained or rusty
Brake disc rusty
Parts missing: Carb and airbox, exhaust, steering wheel, nassau panel, hoses, cables…

The good stuff:

It has a new set of tyres
Brake and pads looks good
Seat is good
Engine is decent and complete
Original electrics is new
Chain, spark plug included
All bearings are good

So there’s little excuse for getting it out running, and researching a bit about the KFS karts gave us some interesting ideas.

The KFS karts are made by a small french non-profit “EvoKart” located near Tours southwest of Paris. They are spec karts made to be as cheap to run as possible and they’ve been around for more than 20+ years now, it seems - virtually unchanged. The particular 100cc IAME engine on this one is a piston ported engine with shorter stroke than most delivering only about 14 hp (on paper). And the racing seems fun with lots of events taking place all over france, the top one being an endurance series of four races with the season finishing at the go kart track at Le Mans. I think these races used to be four hours with this engine, which is remarkable, I think!

They’ve only recently upgraded from the old 100cc IAME to the new Vortex Rok SV, another a detuned engine, but with water cooling also a more reliable one, but they’ve kept the Tillotson carb on the KFS badged Vortex. But the old chassis we have (and we have no idea how old it is) is still legal to run with the new engine.

So here’s the dream: Assemble a team and run this chassis at Le Mans for 6 hours. We’ve been going there as spectators every year since 2008 for the Le Mans 24hr - it will be appropriate to go there to race as well eventually

But first we need to restore it and gain some experience with it.

I’ll post some pictures in a follow up post to this one.

bobakartdad · May 17, 2025, 5:50am

Bimodal_Rocket · May 17, 2025, 9:24am

Bienvenue and Bonne chance with the project! Seems tres cool!

bobakartdad · May 18, 2025, 4:53am

Merci beaucoup It’s great to dream and this is a fun project. If nothing else he will have a kart that we can have som fun in for training. We’re getting the cylinder back from honing today and will then know which piston size to pick up when we’re in France. I’ve had no luck sourcing used parts from Leboncoin.fr as none of the people I’ve contacted there has responded to my messages The leboncoin-platform unfrotunately doesn’t directly support purchases and payment outside of France. But the people from EvoKart has fortunately been helpful so we’re looking forward to visiting them.

Stamatis125 · May 18, 2025, 6:17am

Strip her down completely. Start from ground zero . Cheers from Greece !

tankyx · May 19, 2025, 8:28am

Too bad you cant access LBC : Karting 100 cm3 FFSA - Sport & Plein air

bobakartdad · May 19, 2025, 3:47pm

That’s exactly the kart we have! I can access LBC, sellers have just consistently not responded

We got the cylinder back from honing yesterday and I took the starter, bendix drive, and clutch out too. Interestingly the clutch is completely new. I can’t understand why the engine was not honed. The piston has clear signs of wear. Anyway, we’re rectifying that now.

We’re not going to strip the kart itself yet as we want to run it. I’ve posted a list to EvoKart this morning, will be interesting what they respond. I’ve found all parts elsewhere, so we’ll get it on track no matter what

tankyx · May 19, 2025, 8:08pm

If you contact them in English or approximate French, they will assume you are a scammer

Bimodal_Rocket · May 20, 2025, 3:05am

Sacrebleu! What is approximate French?

bobakartdad · May 20, 2025, 7:23pm

I am trying my very best

bobakartdad · June 28, 2025, 6:54am

So we’ve been away for a few weeks to do other things, but we haven’t been idling on this project as in min June we visited the factory that built this kart orinally to pick up some parts.

The factory is located in a small village north of the french city Tours, less than one hours drive from Mulsanne where we were camping spectating for the Le Mans 24 hours. We had communicated with Clément, the CEO of the company up front about the parts we needed for the kart and they were ready when we came.

But they were also ready to give us a tour of the small facilities. It was awesome!

Imagine driving through rural France through small towns and alleys lined with beautiful trees in the early summer, then turning right to a small industrial area and a steel building. Nothing special. But inside, they’re making great stuff!

EvoKart started in the 80’s, I think, with an initiative falled Formula 10000: The idea was to build a running go kart that would sell for 10000 French Francs. This later evolved into the kart we have, the Iame based KFS 100, and now as of lately, the current detuned Vortex 125cc water cooled based kart.

Where do they source the chassis, you may ask? They make them themselves. Each chassis is hand welded by parts that are cut, drilled and prepared manually. Engines come in boxes, as do body parts, chromed parts, wheels, etc.

So here are a few pictures of the place. I know it has little to do with the actual restoration of this KFS 100 kart, but it was truly energising to see the pride these people took in the work they’re doing!

Where it all started, the Formula 10000:

My son in front of a batch of finished karts just waiting for their Vortex engines:

The master welder at work:

Clément, the CEO of EvoKart, and my son Jens in front of the factory building:

Needless to say, we’re super motivated to continue our restoration project!

bobakartdad · July 15, 2025, 3:48am

The rear axle is 30 mm solid and it was quite rusty but as it’s a solid one we didn’t feel there was any reason to replace it. Still we wanted to clean it up and remove the bearings and brake disc and rear sprocket holders. Removing the bearings was obviously not easy but worked out with the use of this contraption and a small blowtorch. It was quite a pleasant moment when after applying tension on my tool and blowing heat on the bearing, it finally gave a snap and was free.

The axle still looks rusty, but bearings slide on and off. New ones will ordered.

We’ve stripped the chassis almost totally to clear the rust issues. After buying parts at EvoKart, the son doesn’t have the money for a blasting and powder coat, so we’re apply rust converter where necessary, protective paint and a spray-can coat on top. Let’s see how long it lasts…

Ted_Hamilton · July 15, 2025, 12:53pm

Tres bien!! Vive les karts et les pilotes!
J’espere que je peut voyager la quelquefois.
Peut-etre mon dix ans d’etudier la langue n’etait pas pour rien…

bobakartdad · July 29, 2025, 7:40pm

Visitez EvoKart et les 24 Heures du Mans, la combinaison parfaite!

We have had some good progress with the kart restoration and now have an almost complete kart - a few issues have shown up, though, e.g. this starter:

Not surprisingly, nothing happened when power was applied to it. Storage in moist conditions can lead to the strangest of problems. Fortunately, the engine itself was well oiled and is fine.

After cleaning and reassembly, it works perfectly

EDIT: The following is my mistake. I connected the crank case vent to the fuel inlet and vice versa!

The Tillotson karb is giving me problems though. It’s a used part, but restored by EvoKart. I’m afraid they’ve done something wrong. Problems are:

I can’t blow fuel up to it
It doesn’t pump when the engine is cranked

I think the membrane inside might be incorrectly fitted. Click the picture to view a video showing it cranked.

bobakartdad · July 31, 2025, 6:04am

We gave the engine a quick start today. Everyone here should know Murphy’s first and second laws of karting:

Everything that can fail or fall off the kart, will
It will do so in the most awkward moment

With that in mind, watch this video which my wife did of the test - apologies for the size of the recording, I couldn’t find out how to enlarge it during upload to Flickr. Watch to the end, as they say, and with sound

Bimodal_Rocket · July 31, 2025, 3:13pm

Well that was unexpected!

bobakartdad · August 17, 2025, 10:36am

The kart came with a set of blue Vega’s fitted, the correct tyres for the KFS series.

There’s a small direction indicator on the tyres, and they were fitted on the rims so the direction indicators would point the right way on all four.

However, I just checked Vega’s homepage and the homologation, and now I wonder if that’s correct since one side of the tyre has “VEGA” in blue, and in the homologation, that’s described as the “external tyre wall”. If fitted with the blue VEGA facing outwards, the direction indicators would point backwards on one side, though.

Here’s a link to the homologation for the rears:

Being old, it probably doesn’t matter as they will be hard as rocks, but as they’re completely unused, we’ll use them for the first test runs.

We’ve been occupied with other stuff and even though the kart is 99% ready for the track, we probably won’t go until next Thursday (the 28th)