You drive very well! Question: these older 100cc direct drives… unlike the ka100 etc, they go faster, much faster. More like 125tag correct?
How? I assumed the displacement figure (100cc) creates a limit. But, these rev to 20k.
Just higher revs? If you could spin a ka100 at 19k would you be able to produce the same top speeds as a 100dd?
Even the water-cooled 100cc ICAs that came after the air-cooled ones were significantly faster than a 125cc TaG engine like a Leopard or X30. I think at Dousman it was like 2 seconds difference on a 38 sec lap at the time. Back in the day, the ICC (shifter) record at Dousman was like a 35 something and the ICA record was a 36 something. So they were closer in speed to shifter than TaG.
The Junior ICA I ran was fairly close to Leopard and X30 times.
TJ are you able to explain for a layperson why these older 100cc do so much more with the available displacement than current 100cc?
Is it just that they can run higher rpm?
Tighter tolerances, higher compression, big RPM.
These air cooled and water cooled 100ccs were being rebuilt basically after every session or race day because they were that on the edge.
KAs and TaG engines are hobby engines by comparison.
Ah so compression is part of this. The revs make sense to me, the tolerances as well.
Compression refers to how much air you can squash into cylinder, yes?
More being more boomy? Drawback is heat which causes wear relative to cooler running lower rpm output with less compression?
One thing to remember is that the 100cc formats ran a very low weight. Formula A in air cooled format was 308lbs including driver!
What made them so fast was a ruthless approach to performance. Regulations were pretty sparse. Drivability (outside whatever is optimal for the track) was an afterthought. Reliability and cost, if it lasted a day that was enough 
The KA probably wont get to quite that level because it’s bore and stroke are very different from those open 100cc screamers which were basically square. KA is designed to be a much more tractable, reliable ride. That’s not a slight on it either, it’s great to see a modern take on a 100cc air cooled package and it underlines just how great that kind of package lends itself it a great racing kart.
I know I bang on a lot about the karts of that time, but they truly were absolute thoroughbred, purpose designed racing machines. They just happened to be very small.
Thank you so much! It is my home track since 2005, driven plenty of laps there 
I believe they are faster, in fact I was almost 1s faster than a fast X30 driver at the same track. I think the combination with a lot of rpm’s and low weight is the key. With high rpm’s you could drive with bigger sprockets for more acc.
My complete package weigh 140kgs with me in it
These engines has a lot more compression than a KA that TJ explains 
Turns out my race this weekend is on similar karts to your club 100 jobbies.
#ROTAX MINI MAX 125cc 2 Stroke (EVO)
Seems similar. I shall endeavor to send someone to the dark side in honor of the UK club 100 YouTubers. I am guessing United Karting was inspired by the series.
Came across this. Those old karts may look cute but they sound like the devil.
Indeed. I’ve seen dual engine vintage karts claiming 90HP and only rear brakes 
Rain, gross… Abridged version, cause it gets boring after I take the lead.
CW Kart USA Proto1 in action. Race Weekend 3 on the chassis.
Wow yeah almost identical! How are you getting on?
We shall find out shortly. I have to “qualify” prior to race on the kart. Then they will let me race! It will be a great day I hope as I will also do the rental league race after. I did not expect that there would also be a regular race in the offing so I am very pleased to have a double-race Sunday.
Despite a few years racing x30 I’m a bit apprehensive I. That the last time I drove 2-stroke was ka at DKC prior to pandemic. Alec (race director) tells me that these make nowhere hear the same HP. I should be fine but I doubt I’ll be quick. No practice and straight to race.
A bus stop on the way into pits from track
I’m sure you’ll do great! Weather looks amazing!
According to the blurb Dom’s kart is running the mini max engine restricted in both inlet and exhaust and about 13 hp. The Club 100 karts run the full junior engine at 20 + hp? Otoh Dom is on Mojo D2 much softer than the Club 100 YDS?
So yeah it appears to be the kiddo version but it’s plenty peppy! I did manage to qualify and it’s definitely quicker than a rental kart. It feels more like a 100cc, the kind I drove a long time ago at Jim Halls. I think he had kpv100 which he restricted.He ran them in harder tires than these though.
Have a good day Dom!
When are you planning to be at United? I was there yesterday for a club race.
Just was. I did a rotax race at 12 and then the club race at 6.
Pretty good fun. The lil rotaxes are sorta between a gx390 and a 100cc,
I got the worst one for the first heat and the best one for the second. The club race went speedily today. We were done 7:30ish and did a 15 lap final since it was going so fast, a fun day coming from the back in both finals. Video tomorrow.
Did you go today? I saw some owner karts and bikes when I got there before the TKC race.
They lap a little slower than a 206 senior. Was there on Saturday for the club race, just missed you!
