Most of my friends and a lot of other guys I've seen that used to raced bikes now race Shifter Karts. They went to it because it's higher performance and way safer, it's just not on 2 wheels.

You should give it a shot. Way less expensive than Bikes or Cars and the performance is way beyond both.
Track days are open practice and about $40 a day. Tires are about $200 a set. 2.5 G lateral. Racing is cheaper and easier and lot's around.

Karting is by far the most intense, highest performance, most demanding, fastest and most fun racing I've ever done.

If your not in good to very good physical shape your in for a very rough time. I think thats another reason why the Bike racers go to Karting, they are already in great shape.

Yea, my younger brother used to do Karts and I drove his around local track. Beat the crap out of me :)
I am in good shape but also 52 years old. Maybe I should just go fishing :)

It's like anything else, in the beginning you get really sore and tired because:
* You are using some of your muscle groups in a new way
* You are tensing up in a lot of areas that you won't later when you get it down.

Once you get the technique down and start to relax it's much less fatiguing but it's will still make you sore. Shifters especially require good all around strength, endurance and reflexes.
A 125CC TAG Kart is a great place to start.

There's plenty of guys out there your age and older, some are doing well a the National level.
It's a huge amount of fun and as I said you can't come close to the performance level and bag for the buck with anything else.

Top guys in a Spec Moto 125cc Shifter Kart will turn 1:15 at Streets of Willow. Top older guy class (Heavier) is in the 1:17. Built Moto is a bit faster. Spec Moto is super reliable and you can do a top end rebuild in about 30 min for about $110.

May as well put tz250 motor in it, like Lawson :)
I was thinking about building one with 400-450 motor from dirt bike, 4 stroke.

On a track like Streets of Willow a Super Kart like Lawson's is not much faster. You need to go to a higher HP track like Big Willow.

Super Kart is about 100-110hp 250cc with aero.

White drove a 1:18 at Big Willow in a Super Kart. That's the same time Billy Johnson set the Time Attack record at with his 700+ HP FDMX NSX.

There's plenty of places to practice and race on a regular basis with a 125cc Shifter not so with a Super Kart.
Build your own with a big bike engine and you have straight line rocket novelty Kart that you can't do anything with or go to any tracks and if you could you would be slower.

Yea, that is problem with super kart, you need to rent track for your self :)
1:18 is flying, motorcycle record is 1:19.
What is best time for S2K there?

The fastest NA S2K times I'm aware of are 1:29- 1:30. FI 400 hp 1:27.

Billy's time was a 1:18.55

Sprint Shifter 125CC Karts are drag limited at about 104 MPH and 110 in a Draft so times are limited by that at the big high hp tracks. If the top speed was higher like 120+mph at Streets or 165+mph at the Big Track like some of the High HP cars you would see some really nuts fast times.

What's the top Bike times at Street of Willow?

Record for bike is 1:19 by AMA superbike. It is old, think 10 years ago. They don't go there any more. Local racers on 600 would do low 20's.
I raced suzuki sv650 (75hp little 2 cylinder bike) there with 1:27 my best. That was back in 2001 or so.

S2Ks on RS3 street tires with coilovers and GTC-200 wing - stock motor/power are doing sub 1:25.

Mod class (half interior for rollbar) with NT-01s or the Hankook TDs are running around 1:20-1:22.


The Big Willow records are on street tires. I'm pretty sure an FI S2K with R-comps will be a bit faster than 1:27.

This supports the whole highly technical track advantage going to 4 wheels and more power going to 2 wheels.

Karts = best of both worlds. Cheaper, safer, faster...

I don't have the balls for a bike, plain and simple. I broke my leg snowboarding (it's never been the same) - I can only imagine a bike being worse (although the orthpaedic surgeon said it looked like a motorcycle accident when he pieced me back together... lol!!!). I still snowboard, but new risky activities like bikes are being taken off of the option table. Karts are something I'd like to do when the funds permit (not giving up tracking for karts).

Big willow is not technical :)
Sonoma is technical track but we use different layout. Watching Andrie's video they go long turn 11 and fast turn 1. With bikes we go short 11 but around outside curve in turn one, which is hard braking and slow. Not sure how much this evens out things but 600cc bike will do 1:39 best for local racers.
Laguna 600cc best time is I think 1:26 o 1:27.
I would say this stop and go tracks with tight corners would be better for bikes due to better acceleration out of the corners. Tracks where you keep momentum should be closer but bikes do have top speed advantage.
Thunderhill 600cc bike does 1:49, that is with turn 5, not bypass. Think I saw S2K do mid 50's there (bypass).