Jadecy's racing kart

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I am creating a seperate thread here to respond to a question in a different thread. I don't want to hijack someone elses thread so I thought this would be the best solution. Here is a picture of my kart:

Link:My home page with more picturesThis is what is called a straight rail sprint kart. My kart has a blueprinted KT100 Yamaha competition kart engine. The engine is a 100cc piston port 2-cycle engine that can produce anywhere from 13 to 17hp depending on type of exhaust. Top speed when geared for a sprint road course track is around 60mph.Most of these karts are produced by large manufacturers. In my love of a good project I designed my own on CADD in accordance with the sanctioning body rules and built it. I used aircraft grade 4130 steel tubing (ie chromoly), a pro-tools tubing bender, and a mig welder. Believe me when I say this thing is a real rush to ride on the track. The seat I am currently using is not the one pictured. The one pictured is a wrap-around seat usually used for oval racing. Kart racing is a very popular form of racing and there are many tracks around the country. If yo would like to know more here are a couple links to check out:eKarting NewsBob's 4-cycle kartingWhere I've run my kart:Circleville Raceway Park
Reply:Like I said awesome cart their buddy. It must be a blast to run her on a track.J P Streets Welding LLC
Reply:Jadecy,This is exactly the type of project that got me interested in metalworking and welding. I've been teaching myself and gathering all the needed tools for the last year and a half. Great timing for your post.I have a ton of questions, hope you don't mind.What, sanctioning body rules did you use and where can I get them. How would I find out what sactioning organiztions run in my neck of the woods. What kinds of things do they address regarding fabricating frames etc. All racing up to this point, for me, has been motorcycle roadracing. My bones are getting a little older now and Karting is starting to look like a very attractive alternative, and, I need a project that will satisfy my need for speed. Would love to hear more about your project.Allen
Reply:Go ahead and ask away. With my small budget and lack of time (I have two kids and a wonderful wife that take precedant over my hobbies) it took me 3 years to get everything together. At one point I was told that the only way to weld chromoly was with O/A or Tig. I spent a lot of time saving up for O/A rig that is very useful, but ended up not being used for the project. As you can probably tell chromoly can be welded with MIG. I wouldn't do it on a full sized race car or on an airframe, but on a kart frame it works great. TIG is preferable, but I don't have the money for one of those. As to the sanctioning body, I used the tech book from the WKA (World Karting Association). Most local tracks that do club racing loosely follow these rules. The give specs such as size, type and wall thickness of tubing. They also give max and mins on things like wheel base, tread width, seat position... You can get this manual from the WKA Website. It is cheaper to buy a rolling chassis, but it sure is fun building your own. I get some looks at the track because noone can figure out who made my chassis. I've practiced a couple of times and this year I hope to run a few races. If you would like to purchase the pieces or just some of the parts and instructions to build one like mine let me know and I'll send you a price list.Just keep asking if you have more questions. I'll try to answer!
Reply:How did you notch the tubing ?
Reply:Jadecy,Thanks for the WKA link. I ordered the rule book and got a subcription to the magazine. If nothing else the advertising will lead me into new directions. I'm intersted in knowing, what size tubing and wall thicknes is used in Kart frames? I need to get started practicing my tube joints. I would  think that a significant amount chassis tuning can be done in this area.You mentioned part,  pieces and intructions. Tell me more.Allen
Reply:Jadecy nice cart dude. Makes me remember my Dad . When I was a kid my Dad was always into hot rod cars and we had many and all kinds. I had been begging for a horse for awhile (we had no place to keep one) and one day he comes home from work with this wild looking go-cart. This was around 1963. The thing had 2 McCulloch chainsaw engines on the back 7.5 hp each. It was also direct drive, no clutch. You had to start it on some blocks and push it off and jump on. The thing was definitly dangerous in my hands and after about a week he took one of the motors off. Then he was trying to govern the other one . I don't know how fast it would go but it was a scream to drive. Pretty doon the neighbors were complaining about the noise and he sold it and got me a mini bike. DavidDavid
Reply:quick ???, did you use a torque converter or clutch??,StangnetShop Full Of Stuff. Joey
Reply:I notched the tubing with a hole saw notcher from Harbor Freight. The best hole saws I found were Lenox bi-metal. They last a long time if you use a fairly slow rpm on the drill and use cutting oil. Tubing notcher link The tubing size for a racing kart frame is a minimum of 1-1/8" with an .065 wall. I can't remember the max, but it is somewhere around 1-1/4". There is a specification for tubing type. If you go with 4130 seamless it will be fine. On a racing kart you have no standard suspension. The suspension is the chassis and how it flexes. One of the key points is the waist of the kart (the section at the front that is narrower than the rest).The clutch I use is an L&T 3-disc 6-spring oil bath clutch. One of the most popular clutches right now is the Steel Nytro made by Horstman which is also a wet clutch. The rules for the KT100 class do not allow torque converters or axle clutches in most cases. A wet clutch or jackshaft is used for most two cycles because the lockup is around 8,000 rpm or higher and that would be really hard on a dry clutch.Parts: I can put together a kit of all the basic materials to build a frame or I will sell the parts seperately. You would have to do all the cutting to size and coping (ie. notching) of the tubing at the ends. I also wrote a set of construction instructions that give some guidance. The main parts of the frame that are difficult or take special tools to make are the pieces with bends in them. The side rails have a compound bend and is the most difficult.Picture of parts:framebumper - nerf bars