How to Disassemble and Build a Kart
By Richard Curtis
Woodbridge Kart Club
Search as you will, you won’t find many directions on how to assemble your newly bought kart or how to rebuild a used kart. Most karts purchased from manufacturers, even through kart shops, do not come with assembly instructions. At best, the kart shop owner will help with some verbal directions. Or you can pay the kart shop to assemble it for you.
Perhaps you’ve had a previous kart and can call upon some of those experiences in disassembling and reassembling a kart. Perhaps you have a friend, or if you’re a member of Woodbridge Kart Club, you’ll be assigned a mentor to help you through those trying times. Or perhaps you’ve stumbled across a book with some detailed directions. This document hopefully will guide you with details and directions not generally available.
If you want to know how much labor is involved in putting a new enduro kart together, one experienced karter recently said he wouldn’t do it for less than $1,000. That’s a lot of hours and an indication of just how difficult and time-consuming the process can be.
Disclaimer:
While the following article deals specifically with taking an enduro kart completely apart and rebuilding it, most of the procedures will apply also to sprint karts. Thus, the following also can act as a guide to putting together a brand-new kart. This instructions are meant only as a guide. Your success or failure in correctly assembling a racing kart depends solely on you.
Preparation:
Before you begin the disassembly process, prepare your work area. I like to empty out the garage. I have a homebuilt kart stand on casters that I can roll easily around the work area (and actually roll it into the driveway for cleaning the kart) (see below). This makes work easier since I can move the kart around if necessary rather than walk around it all the time. I also set aside a note pad and pen where I write down things to be done as they occur to me. I make a separate list for items I need to buy (fasteners, WD40, etc.). Over the life of the project these lists actually save time.
You’ll be best advised to have a dry, warm place (since most of this work is likely to be done during cold-weather, non-racing months). And plenty of light is always advisable. A moveable light, such as a work
light, is also handy.
Tools: You will need only a few tools, surprisingly. I recently disassembled an enduro kart using a few Allen wrenches, two 7/16 inch wrenches, two 1/2 inch wrenches, two 9/16s, one 5/8s and similar sizes in sockets, a ratchet, an extension, wire cutters and some locking pliers. Throw in a few screwdrivers, an occasional hammer and hacksaw and that’s about all the tools you’ll need. I did find that a reversible, battery-powered drill with a Phillips bit and a socket adaptor speeded things along considerably. Air tools, of course, are always helpful especially in the disassembly process. For reassembly, you will need to add a tape measure, chalk, torque wrench, new hardware, cotter keys, safety wire, etc.
Other stuff: Cleaning rags, WD40, thread locker, parts cleaning solution, paper towels, sandpaper, a wire brush, an old toothbrush for cleaning small parts, 0000 steel wool, degreaser, primer and paint (and perhaps some body filler if you’re repairing old bodywork), safety wire, master cylinder and brake caliper rebuild kits, new brake line, brake fluid, a whole lot of assorted tie wraps, new fuel line and a new fuel filter. You might also need some steel strapping for bodywork brackets, large fender washers, several marking pens (because you’ll lose at least one of them) (you’ll find it after you finish the project), masking tape, pop rivets, Dzus fasteners, aluminum and metal polish, and perhaps some fiberglass repair materials (cloth and resin).
You’re also going to need WD40, Brake Kleen, hand cleaner, all those graded nuts and bolts, grease and oil remover. You might also need new wheel bearings and spindle bearings, brake pads, various taps and dies, a drill and drill bits, a hole saw, a jigsaw, metal shears, a long straightedge, and various other tools including a Great Big Hammer (because you just know you’re going to need it).
Disassembly and cleaning:
Before you disassemble the kart, either take photos of the assembled kart with special attention to subassemblies such as the rear axle and steering. Or make drawings of those assemblies. Another good tip (this from a novice rebuilding his first kart) is to videotape everything as you go, making your own running commentary.
Remove the motor and set it aside for work later. Remove the transponder and gauges. Take the kart outside and spray it liberally with high-pressure water from the water hose. Spray a cleaner over it (I like Castrol Super Clean but Simple Green, Formula 409, etc., all work just as well) especially on the gunkier parts such as around the motor mounts, around the brake cylinders and wheel bearings. Take a brush and rag to the kart, and clean it as thoroughly as possible. You’ll find that no matter how well you clean the kart while assembled, that when taking it apart LOTS more cleaning will be necessary. But this initial cleaning will make subsequent cleaning a little easier.
I like to use boxes, coffee cans, plastic tubs, trays, margarine containers, etc., into which I place various subassemblies (rear axle bearings, bodywork fasteners, brake parts, etc.), keeping them separate. (This makes reassembly just a little easier.) I also like to clean and polish parts as I disassemble them.
Parts cleaner: A good, regular parts washer is a wonderful thing, although it stinks up the garage and can be a fire hazard. I made a temporary small parts washer using two one-half gallon plastic ice-cream containers. I drilled a lot of small 1/8-inch holes in the bottom of one container and inserted it into the other. Into that I drop all the small parts, nuts, bolts, etc. as I take them off. I make my own parts-cleaning solution using a mixture of kerosene and automatic transmission fluid. Pour some into the paired containers. (After you’re through, pour the used stuff into a closed metal container and take it to your neighborhood waste-collection center.) Using a parts-cleaning brush I brush all the gunk off the small parts (nuts, bolts, hubs, split collars, split rings, etc.). When clean, simply lift out the container with the holes allowing the cleaning fluid to drain back into the other container. Sort of like a double-boiler (but for your marriage’s sake don’t use the spouse’s double-boiler especially if you think there’s a chance you’ll get caught).
I find that nothing removes fuel-oil gunk better than Bleche-White whitewall tire cleaner. Simply spray it on plastic parts and hose it off (don’t use it on aluminum). On stubborn deposits, you might need to use the parts brush. Your plastic parts will look like new.
After I’ve cleaned all the subassemblies and other parts, I clean everything else thoroughly (and polish the metal parts at the same time if necessary) with either Scotchbrite pads or 0000 steel wool. On aluminum wheels, axles, fuel tanks, etc., I also use Mothers Aluminum Polish. On the steel parts, I’ll use a metal polish. On fasteners that I plan to reuse, I clean the threads with a brass brush, spray them liberally with Super Clean and polish them to like-new condition. Old toothbrushes make good small-parts cleaners. A good supply of rags is a good thing to have handy also. A buffing wheel and some jewelers rouge can make metal parts look like new.
Inspection: As you disassemble the kart, do a thorough inspection on all the parts at the same time, making notes on which parts need replacing. Look especially closely at brake pads, brake lines and fittings. This is a good time to rebuild master cylinders and wheel cylinders (they are very simple devices and the rebuild kits cost very little, surprisingly) (see below).
Frame: Check the frame for cracks and for squareness. I use a four-foot, I-beam type level and an accurate tape measure. Even better than a tape measure is a long aluminum or steel rod for establishing reference points. A carpenter’s square can also be handy.
Frame alignment:After the frame is stripped completely of all subassemblies would be a good time to measure it for square and parallelism. Stretch your tape measure from the left kingpin (spindle bolt) hole to the right rear bearing hanger (or mark this distance on the aluminum or steel rod). Note that measurement and the exact reference points. Be very careful to use the exact same reference points on the right kingpin and left rear bearing hanger, pull another measurement (this is assuming that — like most enduro karts — your kingpins and bearing hangers are equidistant from the kart’s centerline). These measurements should be within 0.25 inch of each other, preferably less. If the measurements vary more than a quarter inch, you should either have the frame straightened or buy a new frame. Note that these measurements can be within acceptable limits and the frame can still be bowed longitudinally. The only way to measure that is to lay the frame on an absolutely level surface (a surface plate?) and see if it rocks significantly front to rear or is bowed up in the middle.
At this time, I also ensure that the rear axle centerline is perfectly parallel to the front wheel centerline. Install the rear axle (see below). Using the aluminum or steel rod, mark the distance from the left front kingpin to a marked spot on the left of the rear axle. This measurement should be the EXACT same for the right side.
If you have access to a surface plate, this is also a good time to ensure that the ends of the rear axle are equidistant vertically from the surface plate. If not — and to adjust the parallelism noted above — auger out the mounting holes slightly. When you reassemble the rear axle, before tightening the fasteners tightly, ensure that the axle is the same distance off the surface plate on both sides and that the axle is parallel to the front wheel centerline.
You also should check the front spindles for equal caster and camber. You can do this using a very flat surface (a surface plate for all these measurements is best, but a reasonably flat cement garage floor should work also; the dining room table would be another option but do so at your own risk) and a framing square. To measure camber, set one edge of the framing square against the floor perpendicular to the longitudinal axis of the kart, the other against the bottom of the spindle. Measure the horizontal distance between the framing square and the top of the spindle. It should be the same for both left and right spindles. (A friend of mine recently found a brand-new frame to be off significantly in this measurement.) You measure caster the same way except the measurements are made from the framing square (placed parallel to the longitudinal axis) to the either the top or bottom of the spindle. These are usually very minor adjustments, if any, but a perfectly square set of wheels is extremely important to a free-rolling and good handling kart. This is like finding extra horsepower over almost all other competitors.
You also can use four weight scales for scaling your kart to set the corner weights accurately.
Brakes:After disassembling the kart would be a great time to rebuild the brake system. Master cylinder rebuild kits are about $13.00 apiece and include a new top plate gasket, a new piston and an O-ring. Simply disassemble the master cylinder by taking off the top plate (four screws in an Enginetics master cylinder) and pouring out the old fluid. Remove the large cotter pin that secures the protective rubber boot. Next, a large vise comes in very handy; place the master cylinder in the vise lengthwise, applying only slight pressure with the vise against the lever arm until you’ve removed the roll pin by driving it out using a drift punch. Then relieve the pressure by the vise and ease out the master cylinder piston. Check the piston bore for scoring or grooves. Slight scratches can be polished out with 400 grit sandpaper; anything deeper and you’ll need to replace the master cylinder housing.
Clean the bore thoroughly, lubricate the bore and the piston and its O-ring with clean brake fluid and replace everything in reverse order of diassembly. Be sure to use a new, stainless-steel cotter pin. Do not mix types of brake fluid; do not use brake fluid that has been stored in an open container or in a plastic container. If you have the slightest doubt about the integrity of the master cylinder or any other brake part, replace it.
Brake fluid: For what it’s worth, most karters I know who run the stock, single-engine classes use DOT 4 fluid. The heavier, faster, twin-engine or shifter karts usually use a heavy duty DOT 4 fluid. Whichever you use, be sure to inspect it often and change as necessary.
Brake calipers, whether front or rear, are even more simple to rebuild but very similar to the master cylinders. Each brake caliper consists of a housing, two pads, a piston with O-ring and the bolts that hold them together. With non-self-adjusting brakes, there also will be an assortment of brake shims.
When reassembling brake components, use high-temperature thread locker on all fasteners and then follow with stainless steel safety wire done in such a way as to prevent the bolts or nuts from backing out. Do not use nuts with plastic inserts as high braking temperatures can cause these inserts to melt and cause catastrophic brake failure. These
