Track Tac

Bent frame

There is no one answer to this. Too many varibles between frames . What frame is it maybe that would help to know. Anyway this is what I do if I had nothing to work with to get started. .

You need a flat surface of some type. Probably the best you will find and cheapest is a 4 x 8 sheet of the MDF and set it as level as you can.

Then lay just the frame on it. With the frames I have used they will lay flat. If they wobble something is wrong.

Before doing anything I would suggest taking it apart, cleaning the frame doing a quick level check on the flat surface and inspecting every weld joint.

Things I look for are:
Obvious cracks.
At the weld joint. Now this is just my experience and I've looked at and welded a lot of frames over the years for people. Look for a slight discoloring of the paint. You will start to see a slightly lighter color to white/grayish line forming.
This is where the weld joint is flexing the most. The brighter the color change to closer to being cracked.
Look at those areas the closest.
Don't grind or scrape those areas for a closer inspection.
If you need to look under the paint heat it up with a propane torch and use a clean stainless wire brush to clean off the paint or powder coat.

As far as actual measurements to take there are to many differences in frame types, frame designs, to even give a good idea of what to look for.
I can give you some general rules of thumb that I use for American made straight rail frames if that is what you have if I know who made it.
 
I like the idea of a surface plate or jig table (if available), but in the garage, a 4 foot level will suffice. Now, some manufacturers will purposely put some bow in the chassis, some points are lower than others (front axle for instance). You'd have to call the manufacturer of that kart to get the right points to check on the chassis (if they will tell you.)

Now, with all that said, aren't ALL chassis "bent?" Put the thing on scales and see if it scales out correctly. Get it dialed in to some good starting point (neutral) numbers. Next, see that you still have a good range of adjustability (spindle heights, camber, LR adjustable cassette with axle level, etc.) Just because a car has been crashed/bent doesn't mean it can't be fast -- I've seen some that are faster after they are bent from an incident. You have to get it on scales though to know anything.


--
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cuts
www.CarlsonMotorsports.com
Celebrating 25 years of service to the karting industry
765-339-4407
bcarlson@CarlsonMotorsports.com
 
What happened is that my first real racing kart was a Yamaha chassis from about 1978 or so, it had been raced at Accord, N.Y. dirt oval, and the R/F was wrecked, so I bolted it down on the 42" table of my big B & S Milling machine, then using my repair skills learned from my Dirty Modified, I used my oxy/Acc. torch to heat and a big adj. Wrench to straighten the spindle brackets, then a hunk of 2 x 4 to get the spindle brackets the same distance from the floor. We won a track championship that first yr. of racing on the old right turn road course at Cuddybackville, N.Y. 1980.
 
First check to see if you have a bent spindle. The way I check them, and even checked my Sprint car chassis tyhe same way is to string them.
Strip it down to the bare chassis, remove everything. Tie a string to the RF spindle saddle and run it back to the RR bearing hanger. Do the same with the LF and LR. making sure they are tied the same way and in the same spot. Now, from the side, sight in both strings. If they are even and you only see one string, it's straight, but if one string is higher in the front or rear, then it's bent. Quick and simple.
 
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corner weight is corner weight, angles being the same... I raced some truly bent lmsc stuff . I guess the sawzall it the true test- if it jumps when you cut it, it's bent
 
FWIW, how many of yez remember before adjustable chassis, when they put a 5 gallon metal can of Christner or Klotz racing fuel under 1 corner and jumped on the opposite side until things worked to their liking? I saw it at Daytona 2 yrs. back, in fact I even volunteered myself for ballast. Many that walked by had no idea of what was happening.
 
jack burroughs said:
FWIW, how many of yez remember before adjustable chassis, when they put a 5 gallon metal can of Christner or Klotz racing fuel under 1 corner and jumped on the opposite side until things worked to their liking? I saw it at Daytona 2 yrs. back, in fact I even volunteered myself for ballast. Many that walked by had no idea of what was happening.
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Back in the 60s, because most karts were mild steel and would get out of whack on a regular basis, everybody learned that technique Jack. Brings back memories, thanks. I can remember many times looking for a nice flat spot in the pits. Bending over the front end lifting one side than the other and comparing what I felt. With a mild steel frame, it was much easier to get the balance right then with the new Chrome Molly frame's.

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.(Al Nunley
 
I had a DAP kart that I bought new, and it used to waste insides of front tires due to a large amount of neg. camber, so much that you could see it. so I tried to bend the front to make closer to zero, and it did nothing but spring back, so out came the oxy-acet. torch and a little heat later it got where it needed to be , never wore tires out again.
 
Our sprint track had mostly left hand turns. I would have my son sit in the kart and lift up on the left front tire and then the right front tire.(you could do that before the days of armor) If it wasn't harder to lift up the RF tire then we'd do the bucket thing jumping up and down on the RF corner until it was harder to pickup the RF tire. Didn't need straight, just needed the RF to be a little harder to pickup. How much harder to lift? just a nuff

ps... always wanted one of them coyote lift it up and read the dial things, so I'd know how much harder to make it to lift. but they cost too much.
 
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