KAWASAKI Z1325
Ralph Ferrand gets his welding gear out to brace the frame of the big Zed!
One thing big Zeds have been much maligned for over the years is poor handling. Whether it was the tyres of the day or whatever, even I have to reluctantly admit that the frames are a tad bendy. So, it makes sense that – if you’re going to tune the motor – you should go down the route of stiffening the frame. There are various methods, including buying yourself some tube and plate and having a go at making bracing where you consider it will do most good, but I went down the easy road of buying a tried and tested PMC kit. PMC is a Japanese company that specialises in producing replica and upgrade parts for classic bikes and they have a massive range of Zed goodies. I buy PMC products from Z Power who can supply anything from the PMC catalogue and give discounts to members of the Z1 Owners Club. Once everything is clean and degreased, the various components of the kit need to be placed on the frame in the position dictated by the supplied diagram. I found that quite a few of the parts needed fettling with a file to fit well. One by one I clamped the pieces in position and tacked them in place with my TIG welder. TIG (Tungsten Inert Gas) welding is the best quality you can get your hands on, but does require a far greater amount of skill and practice than most other forms of welding. I learned to electric arc weld, or stick weld as it later got referred to in common parlance, in the 1970s, when I was a youngster. I bought my first welder, an affordable SIP 140 air-cooled machine, when I was in my early teens. Just as everything else in welding seems to be referred to by an acronym these days, so it is now known as MMA standing for Manual Metal Arc. As a lad it was the only affordable form of welding. It works by having a very heavy current transformer drop mains voltage down to around fifty or so volts. One side of the transformer output is attached to the work piece with an earth clamp and the other to a handle which clamps a welding rod. This is basically a rod of steel covered in a flux.
The rod is briefly allowed to touch the work piece and immediately drawn away to a distance of say ¼in (6mm) causing an arc to be created between the workpiece and the welding rod. This arc acts as a very high temperature flame which melts the surface of the workpiece and the welding rod dribbles into the pool of molten metal under the arc. The secret of arc welding is to maintain an even arc distance by feeding the welding rod in as it is used up. The weld is formed by moving the arc along the line of the two pieces of metal being joined: the flux around the rod burns away creating an oxygen free area around the arc, preventing oxidisation which could contaminate the weld by making the metal burn rather than melting. As the welding rod moves along the joint the flux forms a slag which is removed afterwards. An indication of a good quality weld is when the slag peels away from the weld and can be removed with a gentle tap, but this takes a lot of experience. Stick welding is still used for larger pieces, particularly in the construction industry. Like the sun, the arc generates a huge level of ultraviolet light which will cause serious eye damage were you foolish enough to look at the arc flame with a naked eye. In the old days, you had a hand-held mask with a special green glass window that allowed you to see what you were doing without being blinded. Nowadays we have welding helmets that stay clamped to our heads and a clever electronic glass that allows you to see what you are doing setting up, and as soon as the arc is struck the ‘magic’ glass darkens in a matter of milliseconds to protect your eyesight. Considering how much welding I have done in my life, I have been lucky not to suffer ‘arc-eye.’ Inevitably when welding, particularly when using a hand-held mask, you are going to get the odd flash of weld light. I have known folk get a few flashes and get the evil arc-eye; apparently it feels as though someone is constantly throwing sand in your eyes.
I also learned gas welding, both at school and during my apprenticeship, using oxy-acetylene. While torches and pipes have always been affordable on the second hand market, acetylene and oxygen have always commanded a high price from the likes of BOC. With gas welding you use the heat of the gas flame to melt a weld pool, and then feed metal into the weld pool with a filler rod. The standard gas welding filler rods are usually plated with copper to prevent them rusting in storage. The most popular form of welding out there for the DIY-ER nowadays is MIG (Metal Inert Gas) which is favoured by those in the motor trade as it makes welding thin materials fairly easy. Anyone can learn to MIG weld in a pretty short space of time and there are a plethora of cheap low quality MIG welders out there. MIG works in a similar way to arc welding in that you have a transformer to generate a high current, but instead of attaching to a welding rod covered in flux the current is connected to a wire fed from a bobbin. The wire is pushed through the welding torch and at the nozzle is fed a shield of inert gas to prevent oxidisation. The wire is fed at a constant rate, though the speed can be controlled. The current is also adjustable. The user simply holds the torch near the join to be welded and presses the trigger. The wire spools out, hits the earthed workpiece and an arc is formed melting the wire and forming a weld pool. These cheap machines are not very sophisticated and can have inaccurate feed rates. While are easy to use, I would not recommend welding motorcycle frames with a cheap MIG. TIG welding is, in operation, quite similar to gas welding, though the heat is generated from a high current electric arc. In a TIG torch the electric power is attached to a tungsten electrode and has a ceramic nozzle around it through which an inert gas is pumped to create a gas shield, preventing oxidisation and weld contamination. The cheaper TIGS are scratch start which means that rather like the old fashioned arc welder, you touch the tungsten electrode on the workpiece and then pull it away to start the arc. Better and more sophisticated machines have a high frequency start where you hold the electrode at the working distance from the work piece and then either press the button or better still operate the foot pedal and it automatically starts the arc with no danger of contaminating the tungsten. Once the arc flame is running it will start to melt the parent metal and form a molten pool of metal. Usually you will dip the filler rod into the pool adding material and then move the torch along and again dip the filler road to add more metal. A skilled welder in good welding conditions will leave a weld run that looks not unlike a tiny row of coins placed on top of one
another. Using TIG welders you can weld a substantial number of different metals and alloys. If you wish to only weld ferrous metals then a more basic DC (Direct Current) only welder is fine, but if you want to join and repair aluminium alloys etc. then you will need a welder that can be switched to produce AC (Alternating Current) as well. Good TIG machines often have a host of different controls to adjust, which can be quite daunting to the uninitiated. There are quite a few different welding shield gases available but if, like myself, you want to weld austenitic stainless and aluminium alloys you will really need to use pure argon. The CO2 mix tends to be a fair bit cheaper, and is fine for both MIGS and TIGS for welding mild steels. It’s worth noting that you can buy your own gas bottles these days, rather than being stung for bottle rental by the likes of BOC and Air Products. I find TIG welding hugely rewarding as while it’s not an easy skill to learn, when you do get the hang of it and produce a nice weld it will be massively better than anything produced by point and press MIG. I noticed when I started welding up this frame, that my welding was getting pretty rough; I had assumed that it was because I was out of practice, but when I put on a pair of supermarket reading glasses my welds went back to being properly professional looking again! Welding around frame tubes is awkward to say the least, particularly using a TIG torch and filler rod. At the back of the torch is a cap that covers the back on the tungsten. If you are working in a tight area you can fit a short tungsten (electrode) and use a very short cap as can be seen in the photo. I did blow some metal in with the MIG in the less accessible areas, but soon gave up on that, as the welds were so ugly! The next job was to sort out the engine mounts. I fitted an empty (light weight) set of cases into the frame with some scabby old engine mounting plates to get position. I then got busy with my pillar drill, hacksaw and files to recreate the rear engine mountings that should have been attached to the frame. Given the extra gee gees the monster lump is going to put out I made them a tad heavier than standard. Once satisfied that they fitted well, I tacked them into place and removed the casings so I could weld them up. For some inexplicable reason the barbarian who originally attacked this poor unsuspecting Zed decided to sandwich the rose bearing at the end of the rear brake torque arm between two pieces of steel of different thicknesses welded to the frame. This meant that the rose bearing did not work as Mr Suzuki intended. I decided that the easiest way to rectify the dangerous mess was to cut one of the pieces short and strengthen the whole attachment by welding plates either side, making it into a box section construction. I machined up a piece on the lathe, from 316 stainless that would allow the torque arm to fit properly and move with the swingarm. Rather than write a thousand words to paint the picture it’s far easier for you to look at the photos. Next month I will continue my work turning the frame into a safe environment for a high power Zed lump!