JACK PHINN’S PURPOSE-DRIVEN KTM 350SXF PROJECT BIKE

Jack Phinn struggled with the setup of his 350SXF, made a few mistakes along the way, but finally dialed it in.

BY JACK PHINN

You have probably never heard of me, unless you’ve been around the SoCal motocross scene for the last 35 years. I want to tell you my story—not to make me famous, but to tell you about my journey to build a purpose-driven KTM 350SXF. My goal? To build a bike that was perfect for a short rider. It is a long story, but the time had finally come to put up or shut up about coming back to the sport I love. A few years ago, I switched to downhill mountain biking, but I had told Jody more than a few times that I was coming back to motocross. He didn’t believe me. He said I was “the boy who cried wolf.” I had quit moto because of a few big crashes and just as many surgeries (both wrists, both elbows, both shoulders and both ankles). The icing on the cake was in 2009 when I broke my shoulder, humerus and C5, C6 and C7 vertebrae in a big crash. After I recovered from that crash and surgery to put plates and sacrews in my neck, I switched to downhill mountain biking—not that it was any safer. Not long after I started mountain biking, I crashed at Mammoth Mountain doing 53.2 mph at the Kamikaze Downhill, resulting in a broken lower back that required more surgery, plates, screws and the fusing of L2, L3 and L4. Once my injuries healed, I went back to downhill racing, but I had a few more big get-offs and subsequent shoulder and elbow surgeries. I decided that motocross was a lot safer.

I remember when I stepped away from motocross the first time to take up mountain biking, Jody told me, “Riding a downhill mountain bike is like riding a motocross bike in your underwear.” I was beginning to believe him. My connection to Motocross Action and Jody goes back decades. I first met him in the 1980s when my buddy Ed Arnet worked for MXA. Jody Weisel ran both Motocross Action and Mountain Bike Action and used me as a test rider at both magazines. In fact, I was on the cover of Mountain Bike Action several times. At MXA, I became the chief minicycle test rider, even though I was way older than the typical mini-kid. Jody said that he was tired of trying to get detailed test information out of 13-year-olds who answered questions about the bike’s performance in one-word sentences. At 5-foot-4 (on a good day), with a wealth of racing experience, I was plopped down into the saddle of MXA’s 85cc test bikes and told to write test reports. It was fun and turned out to be very valuable when I started my own high-end minicycle company called Bigminis. I ran Bigminis during the pit-bike craze, and my top-of-the-line Kawasaki KLX110s were selling like hotcakes for $14,000—right up until the crash of 2008 and the Chinese knockoffs dropped the bottom right out of the pit-bike craze.

“AT 5-FOOT-4 (ON A GOOD DAY), WITH A WEALTH OF RACING EXPERIENCE, I WAS PLOPPED DOWN INTO THE SADDLE OF MXA’S 85CC TEST BIKES AND TOLD TO WRITE TEST REPORTS. IT WAS FUN.”

When you weigh less than everyone in your class, you don’t need to spend money on hop-ups.

I knew that Jody didn’t take my threats to return to motocross seriously, since I had been making them on and off for almost nine years. And, I made matters worse by telling him many times that I’d see him at Glen Helen for next week’s race and never showing up. Jody has a way of looking at you when you tell him something he doesn’t believe that makes you want to prove him wrong. So, after one especially withering look, I was done being “Wolf Boy” and drove straight to my local KTM dealer and bought a KTM 350SXF. I immediately started making calls and ordering parts to modify the bike. Yes, I knew that the stock KTM 350SXF was more than enough, but anybody who knows me knows that I can’t leave well enough alone. I like working on mechanical things. It gives me an avenue to channel my over-the-top OCD. Plus, like many motocross racers, I’m of short stature. I can’t touch the ground when I’m sitting in the saddle, so if I don’t modify the bike, it feels like I’m riding a teeter-totter.

“I DEVELOPED A PLAN TO CUSTOMIZE MY KTM 350SXF TO BE PERFECT FOR A SHORT RIDER. I’M NOT ALONE IN THIS PURSUIT, AS MOTOCROSS BIKES SEEM TO HAVE GOTTEN TALLER AND TALLER WITH EACH PASSING YEAR.”

A custom-made brake tip raised the rear brake 15mm

So, I developed a plan to customize my KTM 350SXF to be perfect for a short rider. I’m not alone in this pursuit, as motocross bikes seem to have gotten taller and taller with each passing year. Here were the basics of my plan:

Footpegs. I ordered two sets of titanium Raptor footpegs and machined the teeth off of one set and TIG-welded them on top of the other set. I wanted to raise the footpegs by 15mm. It worked great. Now, when I stood up my butt actually had clear air space between it and the seat. With the footpegs 15mm higher, I had to raise the shift lever. This was easy. I just moved it up one notch and it still had clearance for the countershaft sprocket and chain, but the brake pedal was way too low. I had a friend machine me a 15mm-taller brake pedal tip and mounted it on the 10mm-shorter 2016 KTM brake pedal.

A Pro Circuit shock linkage lowered the seat height.

Seat. I have always had to cut the seat foam down on my race bikes by 3/4 of an inch and reshape the foam to be more rounded on the edges (you have to shave the sides down because when you cut the seat height down the foam gets wider). Cutting the seat gives you the advantage of being lower but takes away some of your ability to slide forward. It’s give and take. When you cut a KTM SXF seat down, there is a hump in the plastic seat base that has very little foam covering it. I didn’t think it would be an issue, but when I was breaking in my engine, I G’ed out on a landing and hit my tailbone on that hard plastic hump. I bruised my tailbone so badly that I couldn’t ride my new bike for a month. When I recovered, I cut the plastic hump out of the seat base, but I still didn’t like it. I was giving up too much mobility with the cut-down seat. I went back to the stock KTM seat with Think Technologies lightweight foam. This setup made my 350SXF nice and flat thanks to the taller Raptor pegs and low-profile handlebars.

Handlebars. For shorter riders, I find that lower bar bends make a huge difference in the cockpit setup. They allow me to move farther forward and put more weight on the front wheel than I can when my arms are reaching up for taller bars. I run Pro Taper Carmichael-bend bars because they are low and straight. Most short riders will benefit from a straight bar bend as opposed to bars that are swept back too much. My only other addition was a Ride Engineering HPSD steering damper kit. It mounts the Honda HPSD steering damper behind the KTM front number plate. 

“ONE OF THE ADVANTAGES OF BEING SMALLER IS THAT YOU DON’T NEED TO SPEND A LOT OF MONEY ON ENGINE HOP-UPS. SINCE I ONLY WEIGH 130 POUNDS, A MODERN FOUR-STROKE MOTOCROSS ENGINE FEELS LIKE A TOP-FUEL DRAGSTER WITH ME ON BOARD.”

The Pro Circuit exhaust system added snap.

Engine. One of the advantages of being smaller is that you don’t need to spend a lot of money on engine hop-ups. Since I only weigh 130 pounds, a modern four-stroke motocross engine feels like a top-fuel dragster with me on board. They say that every 7 pounds of weight is the equivalent of 1 horsepower. Given that I weigh 45 pounds less than the average 175-pound rider, my weight alone is worth 6 horsepower. I don’t need high-compression pistons, ported cylinders, bigger valves, hot camshafts or race fuel. My body is where my horsepower advantage lies. All I did to my KTM 350SXF engine was install a Rekluse TorqDrive clutch and a Pro Circuit Ti-6 exhaust system.

Suspension. I had TBT suspension shorten my KTM’s rear shock with a 2mm spacer and forks with a 3mm spacer (and I added a Pro Circuit shock linkage to lower the rear of the bike). I rode it a couple of times at Los Angeles County Raceway and spent a lot of time trying to find the sweet spot. When I told Jody what I had done, he gave me one of those looks that I dread. He said that although lowering both ends at the same time and adding a link sounded like a great idea for a shorter rider, it opened up a can of worms when it came to finding the correct valving. I told him that I had ridden it at LACR and it worked pretty well. He said that I needed to ride it someplace rougher. Jody was nice enough to tell me to come to Glen Helen the next day and he would bring two lightweight MXA test riders to ride my bike and tell me what they thought. After the first MXA test rider came in, he said, “That is the worst suspension I’ve ever ridden.” The second test rider came in and said, “Everything on the bike felt nice except for the fact that the suspension didn’t work anywhere.” That was a hard pill to swallow. I was a little bummed but not too surprised. I do know that lowering suspension is a give and take. You give up something to gain something. In this case, the MXA test riders told me that the juice was not worth the squeeze. In my defense, I hadn’t ridden a motocross bike in 9 years and had nothing to compare it to. The MXA test riders were on their game. They ride all the time, and they get to ride every bike made. Glen Helen is a different animal compared to most other tracks. LACR is quite a bit smoother and pretty high speed. Glen Helen is anything but smooth; it’s fast, rough, steep, loose, deep and rutted.

“HE SAID, ‘JACK, PERHAPS THEY ARE WRONG ABOUT YOUR BIKE. WHY DON’T YOU GO OUT AND RIDE IT ON THE SAME TRACK THAT THEY JUST RODE IT ON.’
YIKES! IT ALMOST KILLED ME.”

I don’t know if Jody felt bad for me, but he said, “Jack, perhaps they are wrong about your bike. Why don’t you go out and ride it on the same track that they just rode it on.” Yikes! It almost killed me. I spent the rest of the afternoon apologizing profusely for all the dirty looks I gave them after they told me my bike was terrible. My suspension was a mess, but it was a blessing to find out how far off it was.

Now that I had ridden my bike at speed on a rough track and gotten the free opinion of a couple Pro test riders, I set out to fix it. Jody suggested that I put the forks and shocks back to their stock lengths. I did what he said, and it was better. A couple weeks later, I was finally back to racing again after nine years away. I was loving it, but there were moments on the track when my shock would step out unexpectedly. I decided that I needed to return to the stock valving or have it re-valved to better specs. There was a guy in my races at Glen Helen named Ron Shuler. He and his dad run a small suspension business, and he said that he could redo my forks and shock so that they would work for my weight and speed. His ESR company had cult-like status at Glen Helen, so I gave my stuff to Ron Shuler and he brought my suspension up to my truck the next weekend. I bolted the forks and shock on just before practice and went out on the track. I felt like I was riding on feather pillows. I went 1-1 in my motos that day. Thank you, Jody and the MXA crew, for all your help and support over the years. I’m back in the moto life that I missed and love so much.

The KTM 350SXF isn’t tall, Jack Phinn is short.

When push came to shove, I had built the bike of my dreams into a nightmare of sorts. Luckily, like most local motocross racers, the only thing on the line was my pride. I wasn’t making my living racing motocross bikes, although the purchases I made contributed to the livelihood of a lot of people in the moto industry. I could afford to make mistakes, rectify them and move on to the next mistake. I hope some of my mistakes—and successes—help guide you on your path to motocross nirvana.

JACK PHINN’S KTM 350SXF PARTS LIST

ARC levers: www.arclevers.com

Boyesen water pump & cover: www.boyesen.com 

Cycra plastic: www.cycra.com 

Dubya USA wheels: www.dubyausa.com

Dunlop tires: www.dunlopmotorcycletires.com

ESR suspension: (760) 949-0942

LightSpeed carbon fiber: www.lightspeedcarbon.com

Maxima oil: www.maximausa.com

N-Style seat cover: www.n-style.com

ODI grips: www.odigrips.com

Pro Circuit exhaust/linkage: www.procircuit.com

Pro Taper bars, chain & sprockets: www.protaper.com

Raptor footpegs (modified): www.raptortitanium.com

Red Label graphics: www.redlabelmx.com

Rekluse TorqDrive clutch: www.rekluse.com

Ride Engineering HPSD kit: www.ride-engineering.com

Think Technology seat foam: www.thinktechnology.us

Works Connection air valves: www.worksconnection.com 

Troy Lee Designs: www.troyleedesigns.com 

 

      

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