We buy a 2016 KTM125SX off Gumtree and build the ultimate two-stroke weapon.
STORY CONOR FRASER PHOTOGRAPHY CADE MOONEY
Growing up riding and racing motorcycles as a child, I cast my mind back to a memory of my adolescent self, face pressed hard against the mesh fence spanning the perimeter of the Coolum Pines motocross track. It was the King brothers that day that battled it out for a championship on a track that I myself raced on just weeks earlier. Some 15 odd years ago now, its moments like these that are etched into my mind as I remember what the pinnacle of our sport here in Australia looked and felt like. At this time, thoughts and dreams of lining up to race one of these events were merely that, dreams… Nearly 20 years later, this dream was set to become a reality as I scrolled the pages of Gumtree looking for a used 125 to compete in the final round of the 125 Gold Cup, which is held as a support class along-side the MX1 & MX2 championships at select rounds.
The “Nigerian Prince”
With little to no luck finding anything suitable in the greater Sydney region, I set about broadening my search parameters to entertain purchasing something a little closer to Coolum QLD, where the race was being held. 3 pages into my search and I had found my diamond, or what I had thought was my diamond… A 2016 KTM 125 SX with a healthy amount of aftermarket accessories in what seemed to be fair condition.
With little to no luck finding anything suitable in the greater Sydney region, I set about broadening my search parameters to entertain purchasing something a little closer to Coolum QLD, where the race was being held. 3 pages into my search and I had found my diamond, or what I had thought was my diamond… A 2016 KTM 125 SX with a healthy amount of aftermarket accessories in what seemed to be fair condition.
Some low ball offers and back and forth over email, and we agreed on a price a handful of pineapples ($50s) over the $3k mark, but not without drama. The deal took a turn south when I expressed that I would like to EFT the money without viewing the bike and arrange for a 3rd party to pick it up. With the appearance and integrity of a Nigerian prince, I set about calling a few old friends from the area to see if I could have someone persuade the buyer into not blowing up the deal! A few hours later and it turns out we had a mutual connection with a local trainer who was able to smooth things over and make it all happen.
NEED VS WANT
I set about tearing the bike down in an effort to understand what products I “needed” to go racing versus those that I “wanted” to go racing. Given the bikes location in QLD, I reached out to Daniel at MXRP to see if he could help out with the project. His workshop is only a short drive from the Coolum track and from past experiences, he is in my opinion one of the best Suspension Tuners and Engine Builders in the country. A few days later I arranged for the bike to be dropped off to MXRP where we soon began to realise that there were a few more problems than expected….
Buying a 2nd hand bike sight unseen is never a great idea, and I paid the price with this one. Although the new plastics, brake pads and grips are some of the first things you notice on the bike, that’s about where it ended with the good news. Chassis & suspension wise, pretty much every bearing was past an acceptable tolerance, from shock mounts to linkages and even the wheel bearings. All Balls Racing (Distributed by A1 Accessory Imports) is the logical choice for this scenario, and with a quick visit to MXstore.com.au I had all the necessities at MXRP’s door ready for Daniel to press in the following day.
Although not un-expected, our bad news continued to snowball as the engine came out and Daniel started tearing everything down. With sponsors and partnerships formed, the last thing I wanted was for the bike to quit during the races, given the time money and effort that went into the build. A piston a few hours beyond its intended life meant that we were dealing with a barrel that also had some scars that couldn’t be honed out successfully. With that we also discovered a fair amount of movement in the crank, which at the least would have required a new rod kit.
A quick assessment of the bank balance and a phone-call to KTM Australia resulted in the arrival of series of top and bottom end genuine parts that included but wasn’t limited to a complete crank, clutch basket, new cylinder/barrel and an SXS piston kit. These costs were never allowed for but, as I am sure anyone who has built a 2nd hand bike before knows, once you get into it, you find yourself moving boundaries and spending that little bit more to make sure you have the best possible outcome.
Back together it was for our little 125 engine, but not without some extra TLC from MXRP. As bikes become better and better from the OEM’s, Daniel explained to us that the days of top end only modifications by the way of a quick port job and an exhaust no longer provide the sizable gains they once did. For that reason, MXRP has recently invested in some highly specialised equipment, focused on the performance advantages made in the bottom end of a motorcycle. With our crank trued, cases matched and the tolerances tightened in the top end, I was confident that I had not only a solid and reliable package (as literally every engine part was new), but I also probably had one of the better engines that would be lining up on race day.
BUILT NOT BOUGHT
Now only about 10 days out from the race, I found myself in QLD with the task of getting all the final touches in order whilst juggling my standard workload from the road. The team at JTR have a huge selection of aftermarket products for just about any off-road motorcycle, so naturally a partnership with them was a perfect fit for this project.
Starting from the top, we threw a set of TAG T1 handlebars (in KX High Bend) onto the standard mounts and wrapped them in some Progrip Grey Single Density 794 Half Waffle Grips. I am a stickler for low profile half waffle grips and these units are some of the best I have used. Keeping with the Progrip theme, a universal seat cover was used to replace the tattered white unit that was on the bike when we picked it up. RHK looked after an entire set of controls from their Flex Clutch Levers on the bars, to the Forged Alloy Brake Pedal and Black Pursuit Foot Pegs down on the foot control side of things.
With the standard wheels resembling a shape more similar to an octagon rather than a circle, the decision was made to opt for a new Talon wheelset, complete with Moto-Master Brake Discs and Sprockets. The Talon / Excel Wheel Set used is in my opinion the centrepiece of this build. Just looking at the finish and build quality of the hubs, and the heavy-duty stainless-steel spokes laced to the classic excel rims gives the bike that true race bike look and feel.
Moving to the Nitro Series of Discs from Moto-Master, I wanted to allow for high performance braking while increasing the wear characteristics over the standard units. With the KTM’s standard Brembo brakes, and the lack of weight to a 125, standard size and fixed discs were used over larger floating options.
Now that the engine had its best foot forward, it was only right to finish it off with a DEP Pipes 2 Stroke “Werx” Expansion Chamber. Produced from high quality CR1 grade mild steel, this unit uses CNC cylinder mounts, in-house laser cut mounting brackets and is fabricated with highest quality TIG and MIG welding. To cap this off and provide that crisp power delivery and note, we went with the “Shorty” option in the DEP range of mufflers.
To read the rest of our Gumtree racer build, including how we set up the 4CS forks, entire list of parts we fitted and how the race day went, check out issue #231 of Dirt Action – available here.
Visit John Titman Racing here to build your ultimate two-stroke!