Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/125699
Q i ... m a.. Q - ~ w Z W ...J <.J "; <.J Radius is cut on steel blank by Jack Fossing. Our subject [or this article was K&G Engineering, picked because they wen: representative of the small pipe shop; because 1 happened to know the owners better than any of the others, and because they make very good pipes. We could just as easily have picked Bob Bailey, A&A, Torque Engineering, or any of a bost of others. K & G, like its competitors has some top riders who are using their pipes and lots of friends who swear by them. Among the more notable riders who are using their pipes are Jeff Wright, Rich Thorwaldson, Jefl Davis, and Patti Domay. In this article however, we are not interested in how good the pipes actually are but just in how they are made. Eacb pipe must start out as a design and part of what tbe customer is paying When the headers are finished, a piece of tubing is cut for the stinger and all the parts are finished. They are now assembled into a jig, clamped into place, and welded together. Depending upon the pipe, it may also be necessary to weld mounting tabs in place, or leg guards or some other bit or piece. Painting completes the construction. This is another area where Dave and Milt are not as well-equipped as they would like to be. Having limited funds, they have preferred to spend money on good quality welding equipment and precision jigs. Neitber they nor the customers that 1 have talked to are overly concerned with the paint for the moment, but they are thinking of dip-painting set-up for the future. As with most ra essive companies, MAKING EXPANSION:( CHAMBERS for fun & Profit Spot welded cones to make room for it. Sometimes the best theoretical design must be sacrificed in the interests of preserving the flesh on the rider's leg or allowing bim to get his foot on the peg. Flat sbeet steel is the raw material of pipes. It must be cut into appropriate shapes and rolled into cones. Since they have not yet been able to afford the necessary machinery, Milt and Dave do tbis operation at tbe Bungay Manufacturing Company up in the valley. The personnel of the Company do the cutting, but Milt and the young racers he employs on a part time basis do the rolling. This saves the cost of a highly paid machinist. When the cones are rolled, they are taken to K & G's own plant to be welded. Each cone is placed in a jig for By Ron Schneiders On two-stroke motorcycles the one element that can produce the most dramatic change in performance imaginable is the expansion chamber. The proper chamber can make a bike sing, while an improper one can make the best motor in the world seem like a dog. Every tuner, amateur and profesaiona! is convinced of two things: 1.) That nobody in the world really understands expansion chamber theory and 2.) that he can make a better chamber than anyone else. Since racers and tUllers are by nature somewhat superstitious, and prone to believing in black magic, the ballie incongruity of these statements «loan'! bother them. Pip~ are made by everyone who has access to a welding outfit from the giants like Yamaha to the novice who wan ts to spruce up !;>.is 90cc trailbike but the best pipes are usually made in small specialty sbops where a racer who has had success in building bis own pipes bas started a small business making pipes for his friends. If he's really good, both at building pipes and at running a business, pretty soon he grows, gets a few contracts and becomes a legitimate "small business". More often, be ope.:ates a few months, ruins his credit, goes bankrupt and goes back to work for sorneope else. It takes a lot of work', nerve, and naivete to start such a business and a lot of competence to succeed. We thought that the readers of Cycle News would be interested in the way these shops design and build their products. for is the designer's knowledge and experience. When an order comes in, Milt Krause and Dave Griffith, the owners, work out a theoretically sound design for the pipe based on the customer's motorcycle and intended usage. The fonnulas that they use are classical two~troke design fonnulas that have been heavily modified by the -personal experience of Milt and Dave. The formuras are no longer mathematically pure, but they do seem to work. When the theoretical design has been completed, _ it. must be modified to fit the motorcycle in questhm. Most often there is not physical room for a pipe of the Decesury dimeftsions, so the pipe is moved undl'"leath the engine, or some other P¥ts Of the tnotorcyetl: are '}loved Cones are rolled on this machine. Cones are ground to perfect fit. K & G is not depending solely upon one product line or one successful item. Plans for the future include tt'e acquisition of a dynomometer for more pre ;ise testing of their pipes and the development of new designs. K & G is also dc!veloping some competition goodies for various machines such as the Sachs and the Hodaka. These include air Dave welds cones together assemb I y process. accurate alignment and spot welded. Then it is removed and the seam is c.ompleted. Dave q the company welder and he lays a bead that is beautiful to behold, putting crescent upon aescent in a delicate perfect ctlain:' After the <:ones are shaped ....d 'welded, they are again put into a jig and out to the proper 'length. Often the cuts must be oblique beeause the two sections of the pipe are not directly in line. The cones are cut on a giant radial saw, calJ~d a "Radiac". When the cones have progressed this far, they are put aside and the header is made. This is the curved 'piece of pipe that goes between the expansion chamber proper and the cylinder. The length of the header Is critical and in fact determines much of the low-end torque characteristic. The machining of the header consists of cutting and shaping it to the right size, cutting slots into it with a die. and press, and extruding the collar so it will fit over the existing head pipe, if any. Loops are welded in place to hold the tensioning springs and the safety wire which Dave considers mandatory. in final ckmer boxes, foot pegs and brake levers. Most of the time at K & G is taken up with building pipes for the. Rickman Micro Metisses, but Dave and Milt try to fit in as many pipes as possible for individuals. Prices start about 530.00. Their shop is tocated at 2353 San Fernando Road, Los Angeles, Calif., phone (213) 222-8778. In the near future we are planning to test the pipes of their company and others and compare them to the stock pipes offered on various bikes. -,.--------, Finished pipe is installed on Micro Metisse and safety wired.