‘12 KTM 350 SX-F – Engineered to Slide
Written by Martin Hodgson.
For a man known as ‘Engineered to Slide’, Nigel Petrie certainly gets how to go seriously fast in a straight line. He also knows a good idea when he sees one. Since 2010, he has used his web presence under the E.T.S. banner to share his ideas, showcase his endless automotive creations and be a place where like-minded creative spirits can push each other to new heights. His latest venture is this Salt Flat Racer based on a 2012 KTM 350 SX-F, but his ground breaking Hilux Drift Ute is perhaps the vehicle that truly put Nigel on the map and spawned a documentary about its build and exploits known as Dream.Build.Drive. So it made perfect sense that as he began this new adventure to concur a land speed record that the cameras would once again be rolling. The results, a movie called Flats, will soon be released. But first, the bike…
It was on a camping trip in the Aussie bush, Nigel giving the KTM Motocross bike the beans, that the idea, the possibility of just how fast the little 350 could go came to his mind. That night around the camp fire his mind flashed back to a family visit to the salt flats as a child and remembered a group, Dry Lakes Racers Association, that run the speed events in South Australia. Thanks to modern technology he was quickly on their website checking the times and was surprised to learn the production record for the 350cc class was just 88mph. He’d be flying through the bush on dirt tracks at that sort of speed, sure the salt would be a huge challenge, but the idea had been planted. With the rule book in front of him there seemed to be only two real choices, run the stock bike in the production class or jump straight to the top of the tree and compete in Special Construction were the rules gave the greatest freedom. For Nigel it was a no-brainer, this is a man who has built a KTM Cafe Racer, a Space Frame Hilux and a host of crazy contraptions in his own back shed, special construction is just what he does.
Inspired by the look of the long and lean 1972 Revell Triumph Vintage Dragster Nigel knew the look he was going for “A 1/8th scale plastic kit from 1972 inspiring a build that’s happening 43 years later”. With his ’67 Harley having the right looking proportions he began to take measurements, being 6ft tall the 1650mm wheel base was stretched out to 1800mm so he could lay down low but the 45 degree rake was spot on. For even further improved aero the plan was to sit just off the back tyre and have the foot pegs level with the rear axle, not the comfiest ride going! With that the rough plan was in Nigel’s head and so with cameras rolling he began the process of stripping down his KTM dirt bike for the components he’d use on the build. From 7pm until the early hours of the morning the bike was torn down, not a tough task for Nigel but done just right for the up coming documentary. The engine and vital components were now liberated and could be hoisted up onto the bench to start the build.
Alloy filler rod was used to lay out the chassis design and help Nigel visualise where parts like the radiator, fuel tank and electrics would go and understand the dimensions he had to work with. A trip to Airport Metals to pick up three lengths of 1” x 0.65 wall chromoly tube and the basis of the chassis was ready to begin. “The frame is the bike, it’s the lines and the strength, there’s no plastic that covers it so everything must be equal, neat and have lines that suit what I believe will be the finished product.” Everything was double and triple checked, measurements taken, calculations made; the rear wheels position was raised up 65mm to create even more rake and a lower bike overall. The frame has been powder coated by Colour Tech and looks as good as it performs, a wise choice given that the salt spares nothing.
With every build Nigel learns more than one new skill but the big challenge for him personally on this job was AC welding. “If this project has taught me anything then its AC welding, before this I had no idea how to do it and how to set the welder/job up to do it neatly” but the results speak for themselves. Nigel fabricated a new radiator using one of the two stock KTM cores and crafted the end tanks himself. But it’s perhaps the fuel tank that will really capture a fabricators eye, with just 130mm in width and 400mm in height to work with there is room for not only the 3 litres of fuel required but it also doubles as a seat, and storage for the wiring loom, ECU and voltage regulator. Fine tuning of the rest of the electricals came very close to race time “I got a new Lithium Ion battery that is so small that it tucks into the under seat section, my lanyard kill switch is on and working great, I shortened the earth and power supply to the starter motor, the entire electrical package on this bike is now done”.
Those front forks are hard to avoid, Nigel could have gone for a set of skinny 30mm conventional items but wanting to keep as many factory components as possible they are the WP USD 4860 units as fitted by KTM. The clip-ons are taken from his 250 Cafe bike and flipped around so the bars sit on the inside of the fork, instantly giving the bike that Salt Flat cred. Amazingly the stock lever assembly is retained on both the brake and clutch side and you scratch your head at just how he does it, Motocross gear on a Land Speed bike, but Nigel makes it work every single time! But the work never stops “Next up I needed to mount the rear brake locating pin, this welds to the chassis and holds the rear brake caliper off the frame, it’s a simple M10 boss that has a 10mm thick tab bolted to it, …some M10 bungs in 2 pieces of 100mm long 1” chromoly tube are the foot pegs, I couldn’t be sure where I wanted these so I made tabs that bolt to the chassis and welded those on instead.”
The rims are stock front and rear, 21×1.6 front with 3.00 x21 Mitas Hobby Motard tyre and the rear 19×2.15 with 140/80/19 Hobby Motard. Spinning up that rear Motard style slick is of course the four-stroke 349cc, single-cylinder, KTM with a big bang inducing 13.5:1 compression and a rev friendly stroke of 57.5mm. It’s not typical of a land speed racer but nothing Nigel does ever is, what is typical of his style however is the stunning exhaust. Made from stainless it twists its way reward with a metal majesty, 1 ¾ inches in diameter out of the head and with a few twists and turns finishing in a 2 inch piece, the increased diameter scavenging some extra gases. The throttle is conventional but the left side uses an ingenious throttle mechanism to allow gear changes with a flick of the wrist, with help from Marshall Cycles it functions like a Swiss watch. With the real throttle pinned a CRF stabiliser helps keep things straight, but a conventional damper is really not required so precise is the construction of the frame.
With that, it was time for Nigel to lift the 70-odd kilogram racer into the back of his van and head off. Well, that would be what a mere mortal might do, but he’d also built his mate Dean a bike to ride the epic journey to the salt flats of Lake Gardner on, and with literally days to spare Nigel built himself another custom so he too could share the journey on two wheels. There is another story there and much more to follow but with the movie on this ‘ride of a lifetime’ now so close to release, you’ll be riding to the finish line on-board with Nigel, up close on the big screen. And with a record to beat of 88mph and a theoretical mechanical speed of nearly double that from his little KTM, you better believe when things hit the flats, it’s going to get exciting. Make sure you catch it.
[Photos by Dean Walters]