Honda’s 400EX—or 400X in this case—has been around since 1999, where we entered it in the Baja 1000 and set a new record for an ATV at 23 hours, 59 minutes and 33 seconds. At the time, it was the most venerable race quad around, but time and technology have relocated the 400X to the trail quad segment. Numerous changes over the years—to the plastic bodywork and the addition of a reverse gear, placing it against a Yamaha YFZ450 in our April 2012 issue—showed it’s still not ready to die out. For that test, we installed an L.A. Sleeve 440cc kit and a Hot Cam, with an FMF exhaust system and STI Tech 4 XC tires. The L.A. Sleeve big-bore kit is under $500 with a camshaft, and the FMF exhaust system is $579.99.
For this installment in the project, we ordered up a host of goodies to make the Honda more protected and comfortable. We enlisted the help of PRM Products, Renthal, Switchfly Throttles and Motion Pro. Here’s what we ordered up:
PRM Products (866) 874-5846, www.prm-atv.com
Control front bumper $109.99
Aluminum nerf bars $289.95
.125 aluminum skid plate $99.95
Renthal (877) 736-8425, www.renthal.com
ATV Race bend bars $74.95
Kevlar ATV grips $19.95
Intellilever clutch lever/perch $184.95
STI Tire & Wheel (318) 255-0049, www.stitireandwheel.com
Aluminum wheels $49.04 each (front)/
$56.41 each (rear)
Tech 4 XC tires $57.10 each (front)/
$74.75 each (rear)
Switchfly Throttle (712) 435-9195, www.switchflythrottles.com
Thumb/twist throttle $180
We started off by installing the taller Renthal ATV Race bend bars, which are taller than the stock bend with less sweep. The stronger bars have a crossbar that gets in the way of the 400’s key pod, so we had to trim the bar pad to make room for the key. Renthal’s taller bar opened up the cockpit of the 400, allowing more room for standing and turning. The Kevlar grips have been among our favorites for a while because they’re soft and tacky but strong and don’t rip easily. Plus, they look great! We topped off the bars with Renthal’s awesome Intellilever clutch and perch assembly, which is a 100 percent billet clutch perch with a spring- loaded cable detent that allows the lever to bend any which way in the event of a crash so the lever doesn’t break. It also has a much better feel than the stock lever and makes the clutch pull shorter.
Switchfly’s new throttle system came to us as a pre-production unit, and final production pieces will be available as you read this. The Switchfly system allows you to seamlessly switch from thumb to twist throttle with the simple flip of a rocker switch, and it’s clean, effective, and allows you to ride all day without your thumb or wrist getting tired. The installation is simple, and the throttle comes with a cable specifically made for your ATV when you order. Switching back and forth between thumb and twist allows you to have the control of a thumb throttle for technical situations with the relaxed grip of a twist throttle for longer rides. It’s a great product that is definitely worth a close look if you have problems with your thumb tiring out.
We bolted up PRM’s tough armor without any issues, which is typical for PRM’s parts as they are made from quality materials and a lot of R&D. Their .125 skid plate is the thinner and lighter of the two (they also offer a .190 plate), but is much stronger than the stock plastic plate. Their nerf bars utilize the stock peg with an extension built in, which saves on the cost. The aluminum heel guard and netted nerf are strong and light as well. Their control-series front bumper is strong and allows much more leverage for moving the front end of the 400X around, plus it looks beefy as well.
The last touch we put on the 400X was to install a set of Honda 450R front shocks that we picked up at an online auction for $220. The shocks required slight clearance grinding on the upper mounts and headlight bracket mount, but fit well, and offer adjustable compression and rebound damping. They work much better than the stock 400X shocks and cost a fraction of a new set. We left the preload alone and softened up the compression two clicks from stock and also sped up the rebound two clicks. Out back, we went in two clicks of compression on the stock 400X shock.
In the April issue, we showed that the 400X with the L.A. Sleeve 440 kit could keep up with the YFZ450 with ease, providing a ton of torque that pulls from seemingly zero engine speed up to a smooth top end. The air- and oil-cooled Honda motor is reliable, strong and starts easily, which is essential for a trail quad.
With the taller bars and Switchfly throttle installed, we could ride the Honda more aggressively for longer periods of time without getting fatigued. Standing up to blitz whoop sections or jump the 400X was much easier, and we found ourselves switching the throttle back and forth dozens of times on trail rides just for fun. It operates smoothly and is just one more thing to play with while you ride. The Intellilever’s pull is smooth and strong and feels great in your left hand.
Bashing over rocks and tree roots is what the 400X was made to do, and now with the added protection from the PRM skid plate and bumper, you don’t have to worry about hurting the machine. We bashed an A-arm hard on a rock, which left a small surface dent, but the stock Honda 400X arms are so strong that nothing bent.
STI’s Tech 4 XC tires are much stronger and grip much harder than the stock tires, almost too much for the narrow width of the Honda, as it tends to stand up on a tire during hard corners. They track well in most terrain, but pack up a little in mud. The polished wheels are light, strong, look great and are insanely inexpensive—you can find the fronts online for $40 each.
The Honda 400X is a venerable trail quad in stock form, and what we have done is modify it in a way we see readers do quite a bit with some new and interesting parts. The Switchfly throttle is a blast to ride with, and the taller Renthal bars make riding much more comfortable. PRM’s aluminum armor makes the 400X stand out more and protects it from the beatings we put it through on the trail, especially the places we can go with the grippier tires. If you have a 400X or 400EX, check out these fine products and go ride!