Some say the best plans are thought up in the pub; well this one came from a conversation at a climbing wall.
I was coming to the end of 4th year of University and had totally failed to find a summer job. Andy and I were chatting about projects and he mentioned he fancied building an off-road buggy. I remembered having seen the Ron Champion book on off-road go-karts a couple of years before and I looked into getting a copy. I got a cheap one from eBay. A few of us were talking about building one and the initial plan was to build one between the three of us. This wouldn’t quite have worked as we were spending the summer spread across the country so instead we came up with the idea that we would build one each and race them at the end of the summer.
As it turned out mine was the closest to being finished by the end of the summer, and I had to go home on one of my fist weekends of 5th year to put a coat of rust encapsulating primer on. It was painted over the Christmas holidays that year.
After our final exam a friend mentioned he was wanting rid of his motorbike, it had a few issues and didn't have an MOT, and after a short (but intense) bidding war between Phill and me phil secured the deal. I decided to try my luck and phoned Tom a few days later to ask if Phill had followed up on his offer, he hadn't and I spoke to phil and managed to convince him to let me have the bike.
I first thought i would be abe to stick the bike in the back of my car, but then decided i didn't want to risk an oil leak on my bright yellow seats. The other option was to load it on the back of a trailer. I was visiting glasgow twice over the course of one week so on the first I had a tow Hitch fitted by Discount Motors on Gallowgate (a very well run business close to the city centre). while waiting for it to be finished I visited Bill's Tool Shop in the Barras to pick up a few things i needed to complete the build. Bill's Tools is another fantastic shope, it has an old fasioned feel to it while still selling any tool you could possibly want, including a few ex-military stuff (handy when you need a 1/2"drive 3/4" Whitworth Socket or something similarly difficult to get hold of) Half my tool collection must have come from this one shop. It is also a local business so appreaciates your business alot more than national companies. With the car finished I headed home past Machine Mart on Great Western Road to pick up a MIG welding kit.
On my second trip to glasgow I took the trailer with me and after dropping into Discount Motors to replace the bulbs on the trailer i headed to pick up the bike from just outside of Edinburgh. I was quite shocked to see the bike for the first time, it was larger than i was expecting and required a bit more effort to get it into the trailer. I first took the front wheel off but it was obvious I needed to do more than this so proceded to take the whole front end off. With all the bolts undone the front end couldn't be removed as the bundle of electric cables was too short. As I only really require the mechanical parts of the bike I made the brash decision to cut through the cables, instantly regretting it. but this meant I could fit the bike into the trailer easily and I secured it down and went on my merry way.
Having got the bike home, I wanted to check the engine ran smoothly before stripping the bike down. It was about this time i started to really regret chopping through the electrics. I worked out which wires led from the ignition to the engine and rewired them. There was one wire that could have been originally attached to one of three different ends but it turned out i dodn't have to worry about that one. I was trying to kick start the bike while holding down on the clutch but not much was happening. My dad stated to look at it with me, so put the bike up on its stand, but also couldn't work out the issue. I was afraid of what th estand would be doing to the garden so put a peice of wood underneith it, raising the rear wheel off the ground. I started just playing with the kick start and suddenly the bike roared into life, cutting out seconds later. It turned out the clutch handle wasn't pulling hard enough to disengage the gears so the rear wheel was wantng to spin.
After fixing the clutch and adjusting the idle screw on the side of the carburetor the engine was running quite nicely and I was able to cruise round the garden. I couldn't take it any further as it has no MOT or tax and I don't have a lisence. Shortly after the handlebars got really loose, all my yanking on it to start the bike had sheered the bolts holding it on, a good demonstration of the pitfalls of cheap motorbikes (it is a Chituma C125, a chinese imitation of a Honda 125cc).
Knowing the engine works it was time to strip the bike, i could have just removed the engine but i need a few of the componants on the buggy and figured I could put the rest of the stuff on eBay to see if I can get some money back.
The Seat and fuel tank were the first things to be removed, two bolts holding on the seat, none holding on the fuel tank, although it was pretty tightly fitted. A couple of times I went to lift the bike on the fuel tank it just slipped off.
There were various ways the roll cage couyld have been made. The best way wouyld have been to use a tube bending tool, unfortunately I wasn't able to get hold of one (everyone I asked either had one that was too big or too small). The best alternative was to cut grooves into the tube and bend it by hand, I tried this but the tube started to flatten at about half way so i cut more grooves in but that didn't help (if i had cut maybe 3 or 4 times the ammount of grooves into the tube and made sure it bent the same at each groove I think it would have worked). With the metal spoilt at the bends I was left with the second alternative, luckily i was able to rescue most of the steel from the tube and had enough spare to make up 5 sections which were welded together to make up the roll cage.
The bike I bought had the engine haning from the top of the chassis, this is slightly different from the bottom mounted engine used in the manual. This meant that the engine will have to hang from my chassis so i had to design the method to do this. The tube left over from the chassis was the correct diameter to support the engine but there was not enough to build anything too substantial, the steel supplier had sent me three extra metres of thinner tube so I decided to use that to add extra support. I used my engine crane to position the engine and built the mount to support it. Tack welded in place, the mount could support the engine un aided, as these are relatively weak welds I assumed the fully welded mount would be able to support the engine with all the vibrations it will create.
The one thing i have been struggling to find has been a suitable seat. I originally wanted a bucket seat but a quick search on eBay showed these to be way too expensive. I figured I could quite easily turn a standard stacking chair into a bucket seat but these retail for £20 so i tried to locate one for cheaper. After months of checking skips and the dump, I noticed a kids go-kart at a "recycling centre" in Glasgow. I asked one of the guys working there if I could take it but he said I would have to come back once his gaffer had left. This seat would have been perfect but it was tiny. Today I reached the point where I could go no further until I had a seat so we phoned the local village hall and managed to blag one of their old stacking chairs, This I will eventually add sides and foam cusioning to. I have mounted the seat at three points and made it so the seat will adjust forward and back, just by drilling extra holes in the mounts.
Time has finally arrived to fully weld the chassis, I started off pretty badly as I am in no way an experienced welder (I bought the MIG welder esspecially for this project) but improved to a pretty impressive weld by the time I finished the chassis. I had blown holes in the roll cage when tack welding so I left this until last and was able to fill the holes with weld.
once the chassis was fully welded I lined up the floor panels and tack welded these on from above, I then cut the floor to the correct size and up ended the buggy to weld the floor from below (the welds I did here where awesome)
first job on the rear axle was to make sure the bearing fit in the holders. They did, very nicely.
I then lined up the axle sprocket tot eh sprocket on the engine, they had to be perfect, I marked where it was in relation to the bearings and put a thick disk in my grinder. the hubs I bought had key ways in them and came with a key but i just bought a steel bar, rather than a specially made axle so it had no key way. The key was only slightly thicker than my grinding disk so i marked its width and ground out a key way slightly longer than the hub needed. It looks rough, but it'll do the job. the above picture shows How I had to attach the sprocket to the hub. only two of the holes matched up so I had to make a circular disk to join the two together, I marked out both the sprocket and hub holes on the disk and drilled them out. I then bolted the sprocket between the hub and disk. this meant they were centered with each other so there would be no undue strain on the chain.
With everything (except brakes) in place it was time to get the engine running again. It hadn't been run since before I stripped the bike down, and even then it was a bit iffy. My dad knows a guy in the nearby town who has rebuilt a few bikes so knows his way around a bike engine. He was happy to take a look so we arranged a date. The only problem was how to take the buggy the 40 miles to where he lives.
Next job was the steering , which turned out to be easier than I was expecting. Hardest job was welding the stub axle holders, which was a wee bit tricky, hence the awful looking welds (I'm reasonably confindent they will hold though) These had to be the exact length of the kingpin holder to ensure a tight fit. The angles are to make steering slightly easier, although they probably should be more subtle than I have managed.
Stub axle welded, I fitted the track rods, the track rods I have used at the wheels are from a Mini, the ones by the steering column are for go-karts. As you can see the steering is very simple, turn the wheel on way it pulls one wheel closer and the pushed the other. and Vice versa when the wheel is turned the other way.
The steering column is held in place by fitting through a ring of steel bolted to a peice of tubular steel welded to the chassis. It's a simpler method than is suggested in the book, but it will work just as well.
i had to veer away from the books method again in this one, as again it seemed unnecessarily complicated. I took the gear change pedal and ground of the pin, then drilled a 8mm hole where it was.
From here I bolted a bent length of bar leading to the gear change lever.
being a motorbike gearbox, you don't have to select a gear, just move up or down. So I can move the leaver forward to move up a gear and back to move down the gears.
After speaking to a few people and having a look at a few trailers we couldn't find anything appropriate and available. By luck on the way home we passed some locals in their Dodge Ram,w e stopped and asked if they had anything we could borrow. They didn't have anything with a conventional hitch but offered to tow it up with the Dodge.
With the buggy in the right place we set about getting the engine to run. After overcoming a few problems (battery was goosed, there was a hell of a lot of unnecessary cabling) the engine ran and it sounded awesome. Unfortunately the fuel line wasn't long enough to join the carburetter to the fuel tank so I couldn't tkae it for a test drive.