While waiting for some engine components, Odgie gets on with a stack of odd jobs on his Can-Am flat-tracker. It certainly needs footrests and a seat and tailpiece. Time for some metal manipulation, then…
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While waiting for some engine components, Odgie gets on with a stack of odd jobs on his Can-Am flat-tracker. It certainly needs footrests and a seat and tailpiece. Time for some metal manipulation, then…
Projects tend to go in fits and starts. There might be a few days or a week or two where there’s a nice concentration and build-up of momentum in one area, then you need to shift focus to another aspect of the build. As I was saying only last month, I’m often reminded of how bike building is an example of life in miniature; the ebb and flow of everyday life being reflected in the mental and physical workings of one small shed.
Bike building teaches you patience, adaptability, durability, determination and resilience. These are all very useful attributes – whether you’re building a worldbeater or navigating the flotsam and fluxes of apparent existence in the space/ time continuum (or simple of ‘being alive’ if you’re not n t a journo j trying t i too impress with extravagant pronouncements...)
Last month we’d started getting stuck into the engine. But the rod kit needed thicker thrust washers (the only available replacement conrods are slightly narrower at the big-end), and they were still being manufactured. No worries, there’s never a shortage of Things To Be Doing, from the exciting to the mundane. Here’s some of them now...
I had planned on making a rear mudguard from scratch, and then making g a fairly standard type t of f seat, much h like I did on the A65. I’d got the alloy sheet out ready, and was contemplating how long and what style to make the mudguard. But the more I studied the back of the bike, the more I saw it being a little too conventional. In fact that shortened rear loop was crying out to be made a feature rather than just a mudguard carrier. Time to break out the card and the creativity then
Sufficiently encouraged by the mock-up, I committed the first section to metal. At this stage it’s still a journey into the unknown. Metal doesn’t behave quite the same way as card, but sometimes you have to follow a direction to find out whether it’s the right or wrong one. See what I was saying about mirroring Life?
Photos by Odgie Himself
I never use tinsnips. I don’t think I even own a pair; they make such a of the edges, endless little mess dents yo u can never get out. Smaller cut out using a cutting bits of alloy I disc in the grinder, but for larger ones plasma cutter. I tend to use the I bought it when I was building cars item for a while, it’s an essential when you’re making more substantial parts from scratch, but it’s been consistently useful for bike par ts too.
Not a thing you use often, but well its value when you do need it worth
With the alloy cut and bent to shape, I could mock-up a little further in card. Sometimes you get it right first time, sometimes you cut the card wrong and have to start again. But card is always cheaper than alloy sheet, it’s much easier to spend 87p than it is to spend 50 quid and wait a week for more alloy to be delivered. This is the second card mock-up as it happens (even at the price of card, I’m still a cheapskate; knowing the first one might be sacrificial, I made it using two old smaller bits of card taped together...), but it’s starting to look like something now
While I was at it, with no mudguard I needed a splash guard instead. I couldn’t just use a flat sheet, as it needed to be well clear of the rear tyre. So I did get to use my plastic mallets and curved wooden block after all. A trickier piece of metal to manipulate than it might appear, once you start hammering the tendency is for the whole sheet to bend, but while the middle needs quite serious double curvature, the edges still need to remain straight. It’s easy to get wrong, so it involves a combination of feel, experience, common sense and courage – did I mention alloy sheet was expensive, the cost of scrappage and wastage certainly focuses the mind
A real shame then to cover it up in many ways. But alloy porn though it was, I need a flowing surface for paint or powder coating. So out with the files and the sander, and an hour or so later it was suitably smoothed
One of the few things I do farm out is alloy welding. I can just about stick alloy together if needs be, but the result isn’t pretty – far from it in fact. So I nipped down to my mate Ben, who kindly did the necessary. When I tell you he makes tanks for the big British Superbike teams from around the country, you’ll get an idea how good he is. Or just look at the picture here...
A bit more bending and curving along the edges using a rubber mallet, and now we’re getting the picture. This is the stuff I love. I’m in my element just fabbing away down the shed, I don’t need company, I don’t even stop for lunch (most days I forget to even drink for several hours), just my groovy tunes playing away and the deep joy and satisfaction of seeing things coming to life in my hands
On to simpler things. I decided on 38% of wheelbase for the footrest position, along with 17 inches back, 29 inches below the handlebars, all fairly straightforward flat-track dimensions. Measure the wheelbase, a quick calculation on the old flip-phone (no swipe screens for me, I’ll stick with ‘beam me up Scotty’ if you don’t mind. Although it’s a sign of the times that your electronic mobile phone choice can now define you as a Luddite). As luck would have it, the footrest position fell perfectly for making up a mounting… and rules dictate it can’t be lower than the bottom frame rail anyway
The rear brake system was fairly straightforward to make, once I’d decided in my head how I was going to do it. The brake plate is fully floating. It sits on a bush when the wheel spindle is tightened, and the torque arm is bushed at both ends. So as the suspension moves up and down, the brake ‘floats’ rather than being fixed to the swinging arm. It allows the suspension to still move more effectively and stops the ‘hopping’ that can occur under braking
I’m not a rules person generally, but common sense is common sense – picking up severed fingers from the track isn’t a nice task (and if they’re your own how do you pick them up anyway?). So for flat track a ‘shark’s fin’ guard is mandatory to cover the chain entering the rear sprocket. I cut a piece out of an old plastic five gallon drum, cut it to shape, heated and bent it 90 degrees, and attached it using a single 5mm stud welded to the swinging arm. You might think it would have needed two studs to stop it potentially rotating, but where the axle plate sticks down slightly under the box section, I cut a corresponding groove in the ‘shark’s fin’, so a single stud still provides positive location. I know an extra-short 5mm stud doesn’t weigh that much, but every little helps, and the sheer elegance of the solution appeals to me
Ditto on the mounting. A simple boss welded directly to the frame, with a small groove cut into it and circlip. Much lighter than a bracket and nuts or bolts, and that’s the beauty of race bikes, they don’t need to do 50 years or 100k miles with a variety of clodhoppered and ham-fisted owners, so they don’t need to be built like something I K Brunel would have been proud of. And yet more adjustability built into the cable anchor. Note also the new gear lever, swapping it from the left meant its original curve was upside down, so I made a new centre section by cutting some scrap steel to a long taper, then used just the ends of the original
Although 38% is a good starting position, depending on everything from track conditions to bike set-up to simple rider preference, a little bit of adjustability is no bad thing. So I’m giving myself the possibility of an inch forwards or backwards. Once I see how the bike handles. If I think I need to try something difffferent, at least I have an easy option
I also needed to knock up a brake lever. Small diameter but fairly thick wall tubing for the lever itself, as the best combination of light weight and core strength, but thin wall tubing for the pivot to save weight. I’m pretty fanatical about weight: refer back to part one for why. Every ounce saved is an ounce I don’t have to make turn or accelerate on the track
I’m using the top tube (formerly the oil tank) as the fuel tank, but a bike needs some sort of tank-type shape. Oh look, here’s a fibreglass cover now... I had the loan of a mould and every intention of making it myself. Until a quote for materials alone came to over 90 quid! At which point our local fibreglasser knocked it up for me for 60 cash…
Cardboard templates are the bike builder’s friend. At least old school builders. I’m sure some people are doing this with CAD (whatever that is) these days
I measured up and cut a hole in the top tube. You can buy ready-made filler necks to suit 2½” caps, so all I needed to do was fab up a bit of large diameter tube, a bunch of measuring and welding, and Uncle Bob came to town. The ring below the neck is a circle I cut from thin steel sheet and welded to the neck with a rubber washer I cut from a bit of scrap, to locate the fibreglass cover once fitted
I made up some little tabs to mount the cover on. I try to make tabs by cutting up box-section or angle iron. You can get that little return on one side, which adds lots of support, whereas a simple flat tab can fracture with vibration and hence needs to be much thicker
Still, once it’s all sorted, the tank does sit nicely and look kinda ‘killer’
Cardboard transferred to alloy sheet, cut out and bolted on, these little tabs are for attaching the tank to…
All of which counts as progress. So much so that I’d reached the stage where I could make a ‘to do’ list. I never make one at the start, it can be self-defeating. If you’re building a bike from scratch it would take so long and run to so many pages you’d never want to start. I missed a few things off, which have been added since as they came to mind, but it’s still an achievablelooking document…
Which I did by fibreglassing them in place. I did both sides to make sure everything was secure, the outside was easy, the inside was less so. Getting resin and mat up the inside and into all the corners was what might be called ‘messy’...
I have a pet hate on bike builds, and it’s cable ties. Cable ties are for putting up road signs, or sorting out the mess behind your television, or at a pinch getting you home along with gaffffffer tape. Cable ties are for finishing bikes when you didn’t think them through beforehand. Oh look, a bit of 3mm welding rod made into a cable locator. The cable is free to move as the forks turn, yet kept well out of the way of the lockstops. You know it makes sense