Last year KTM took the ATV market by storm with their SX ATV line that was specifically targeting the MX and off-road market. Their 450 and 505cc powered machines were outfitted with everything that a racer could ever need or want in a performance ATV. Being offered with a wide long travel front suspension, adjustable rear axle, nerf bars, adjustable steering stem and a whole bunch of other goodies there really wasn't much left that needed modification. The opinion of many in the industry felt that this machine was truly "race ready" out of the box.
This is where Hinson Racing steps into the picture with their years of experience in building high quality race machines. Bryan Hinson had recently acquired a KTM 450 SX and after some seat time at local MX tracks in Southern California felt that the machine could use a few refining upgrades. We're not talking about a complete overhaul like many other bikes might require to be considered track ready, but a small list of items that could make this formidable machine better than it already was. Bryan invited me to a day of testing out at Glen Helen Raceway in San Bernardino, CA to give the reworked machine a little seat time of my own.
When I rolled up to the track, I was slightly taken back from what I saw as a near stock KTM 450SX waited for me to throw a leg over it. Upon speaking with Bryan at the track he quickly pointed out the differences in this machine from a stock unit. The only visible difference from this machine to what you would find on your showroom floor were the Fox Racing Shocks on the front and back, FMF slip-on exhaust system, Scotts steering stabilizer and Hinson Racing Clutch cover. Now don't think that all Hinson added was one of their covers because hiding behind it was one of their trick back torque limiting (BTL) slipper clutch systems.
Lets just start with the explanations of the basics here. The stock WP shocks are good, but as we all know things can always be improved on. Hinson chose to install a set of the Fox Float Evol air shocks that feature their dual speed control (DSC) adjustment. These have been my personal shock of choice since I first rode on them a few years ago. These shocks weigh over half of what a conventional shocks does and do not have any springs which can weaken over time and cause your shocks not to work properly. Simply set the proper air pressure in the dual chambers to control ride height and dampening resistance and all that is left to adjust are your dual compression and rebound controls.
At the rear of the machine, the stock WP rear shock was swapped out with a Fox Podium X rear unit. This is a conventional rear setup like you'll find from most suspension companies but again it's the magic the people at Fox perform on the internals that make their shocks work so good. The a-arms and swing arm are good quality units so they were left alone since the goal is to spend the bare minimum. To further enhance the stability, a Scotts steering stabilizer was mounted to the frame of this machine. Scotts has been a long time sponsor of Factory KTM race teams and it shows since the frame has a mounting spot that is almost a perfect for the stabilizer.
With the suspension being dialed, it was time to see what the Hinson's did to the engine. The 450cc power plant makes a good amount of horsepower so the only modification was swapping the stock tail section of the exhaust out with an FMF Factory 4.1 Slip-on exhaust system. This will allow the KTM to breathe a little better and generate more power through the RPM range. Again, the emphasis on minimal modifications to increase performance is the key to this project.
The only other visible item that was replaced is the quick-change clutch cover on the engine. Hinson Racing swapped the cover out with one of their anodized units, but the parts that are behind that cover are anything but stock. Hinson installed one of their billet clutch baskets which have been the industry standard for anyone that wanted something that was stronger than stock. Installed in the clutch basket was also one of their BTL slipper clutches which I think is a piece that can help transform a good 4-stroke rider into a better one.
According to Hinson, the BTL slipper clutch allows you to eliminate the amount of back torque or engine braking coming into corners or coming down hills. This allows the rear end to stay planted on the ground instead by allowing the clutch to freewheel on deceleration. With a normal clutch system when you come down hills or into corners while you're downshifting the decompression braking causes the rear wheels to drag and can lead to the rear end hopping and instability under braking conditions. This can be especially rough on terrain with severe braking bumps.
With the BTL slipper clutch as you come into a corner or down a hill at speed, you can start dropping gears and the rear wheels will be allowed to keep rolling. While there is still some decompression braking, it is significantly lower than what it used to be. On the acceleration side of the engine, the BTL provides better traction by preventing as much wheel spin compared to the conventional clutch system. If you are looking for proof as to if this system works, all you need to do is ask Dustin Wimmer. This is the same system he ran in his Suzuki LTR 450 to win the AMA ATV Pro Class Championship in 2008.
After we got our still photos done, Bryan Hinson geared up and started burning laps around the REM track at Glen Helen Raceway in Devore, CA. Watching from the sidelines, I was amazed at how this machine sounded and pulled him up some of the steep terrain. The engine never sounded like it was ever struggling. While it's nice to watch a good rider fly around a track, it's even better to get a chance to do it yourself.
I asked Hinson what he thought of the modifications and this is what he had to say. "The motor runs really good and pulls strong in the bottom and mid. You can really feel the difference that the FMF exhaust system makes. Suspension wise, the WP shocks that come on the bike out of the box are pretty stiff. Switching over to the Fox Evol front and rear shocks made a huge difference. Not only did they help lower the ride height of the bike but they drastically helped the handling of it as well."
When I asked him about the Scotts steering stabilizer, he had this to say. " We went with the Scotts unit because the machine was set up for it. It was easy to install and it did exactly what we wanted it to do. There was plenty of adjustment for us to set it up to our liking." All in all I could tell that he was very happy with the end result of his project.
Now geared up and pumped up from all of the positive feedback I've heard on this, it was my turn to ride. As I rolled onto the track the first thing I felt was that I was extremely comfortable on this machine. The ergos were perfect for my larger frame, as I am 6'1" tall and tip the scales at just over 240. By no means am I a pro level rider, but I have been on a good assortment of 450cc machines and know what I like in power and handling.
I found a section of track where I knew I could consistently find a good line. Here I could test all of the components that were added to the mighty KTM and went to work doing so. The REM track at Glen Helen is known for its elevation changes and the FMF exhaust system shined here. I am a rider that likes the powerband of a machine to be more in the low to mid, and the KTM was right where I liked it. While the power shined in these areas, it was still no slouch on the longer straight-aways where it had plenty of overrev and pulled hard in the top.
Since I hadn't ridden this bike in stock form, I really can't give my personal opinion on if they were better than the WP shocks or not. What I can say is that the shocks definitely work. These by far are my favorite shock on the market and can aid in the handling of any machine. Their light weight, great performance and wide array of adjustability make the front Evol and rear Podium X shock a welcome upgrade to anyone that is looking for a good high performance shock setup. From soaking up big jumps, pounding through whoops or being able to attack corners that have been chewed up by a weekend of racing these shocks worked flawlessly. The Scotts stabilizer in conjunction with this setup was perfect as I never felt as if the bars were being yanked from my arms no matter what I hit.
The best modification about this project is truly the BTL slipper clutch. How I was told by another test rider to test the unit was to come down one of the larger downhills in 4th gear and half way down, drop to second gear and just let the clutch out to see what it does. At the base of this hill was a small kicker left by a tractor that was cutting the track and a stretch of braking bumps that accompanied a hard left hand turn.
I did what I was told and what a difference I felt from anything I had ever felt before. Although I had to control more of the corner braking myself, the rear end of the KTM stayed planted on the ground and never felt like it was trying to get around itself. This was also nice for me since I was able to shift into the gear of my choice before getting to the turn instead of having to downshift mid-turn. I was quickly a believer in the BTL clutch system and think it is definitely worth looking into if you're a serious competitive rider looking for that edge against the competition.
The Conclusion
Hinson Racing started this project with a top-notch machine and made it even better by replacing or adding only a few key parts. After having some seat time, I'm convinced that any competitive amateur racer can jump on this machine as it is prepped and be a front-runner in their class. Sure KTM claims that their machine is race ready but there are always upgrades to make a good thing better. Hinson Racing hit the nail on the head with everything that they did to this 450 SX racer. When you hear the name Hinson, you can't help but think championships. This is because they know what it takes to win.
Fox Racing Shox 800/369-7469
www.foxracingshox.com
Float Evol Front Shocks w/ DSC $1495.00
Podium X Rear Shock w/ DSC $995.00
Hinson Racing 909/946-2942
www.hinsonracing.com
BTL Slipper Clutch $1754.95
Kit includes: clutch cover, basket, slipper clutch, fiber and steel clutch plates.