Although we also tried an HRC-kitted TRX450R in our 24-Hour (page 62), we were already lined up to try the kit on a long-term 2006. It was more of a quest to see just how much performance we could gain from a simple Honda aftermarket kit over stock and if it was worth the time and effort. Now, I had an idea of what to expect from the kit after spending some time piloting an HRC-kitted '05 TRX450R. And the new '06 had impressed me in stock form with the chassis improvements and the redesigned engine's performance. So I was excited to see how much an HRC kit could enhance the new 450R.
Part 1: Installation
Just opening the '06 HRC kit, gave me my first surprise; the number of components had doubled compared to the '05 kit. Installation is mostly a no-brainer. The average weekend mechanic who knows his way around today's high-tech four-stroke engine along with his arsenal of basic tools should be capable of performing this operation. Instructions provided by the Set-Up manual, which is included in the HRC kit, are very general. During more difficult procedures such as the cam installation, the Set-Up Manual will refer you to the Honda Service Manual (61HP102) for detailed instructions. Investing in this manual is highly recommended before attempting this procedure. Trust me, it will come in handy time and time again as it has details on every component imaginable along with information to get you through any challenge you may encounter while venturing into any unfamiliar territory on your machine. A good-quality torque wrench will be necessary to achieve proper torque when reinstalling the cam carrier, securing a long, healthy life for your cam. A valve shim kit is a good idea to have on hand as well, since these precious metal parts are needed to obtain proper valve clearances anytime you are replacing or altering the cam. Sure, you can purchase the shims from your local dealer on an as-needed basis or you can do as I did and spring for a Hot Cams shim kit (515/402-8005; www.hotcamsinc.com). It makes the install job simple and helps you be prepared for future adjustments-something you should be performing on a regular basis to ensure this engine is performing at its maximum.
Follow along in the photos as we reveal a few tips and details for an added boost of confidence, preparing you to tackle this upgrade to your new TRX450R.
Part 2: Evaluation
After several hours of wrenching and buttoning up the engine, I was ready to sample its added ponies. Side note: Don't be alarmed if your jetting isn't dialed in the first time you fire up the engine. The 162 main jet included in the kit may be a bit large, causing a sputter in the top-end. A single jet size can't be expected to be ideal in all conditions, and the Honda engineers prefer to err on the rich side, so the 162 is the best overall choice to ensure the machine doesn't run lean and seize. Altitude, temperature or even whether you're running the quad with or without an airbox lid-all will affect the jetting. You'll have to compensate for these factors and find the correct main jet.
Anxious to get this machine back into action, I loaded it up along with a stocker and headed off to the trails to get a good side-by-side comparison. With a push of the E-button, the machine fired up sporting a new deep rumble and an aggressive nature that seemed to be calling my name. I knew at that moment there was more power on tap.
From the initial throttle roll-on, the drastic increase of power revealed itself-coinciding with the quickly rising rpm. This unleashed beast was becoming increasingly vicious as it approached the redline just short of 11,000 rpm. By adding 1000 rpm to work with and increasing fuel and airflow, the HRC kit made a drastic change in horsepower output to this machine, putting the Honda in a league of its own.
Despite the substantially increased power, it's not overbearing and is more rider-friendly than most highly modified engines. Besides more power, the HRC-kitted Honda's quicker throttle response means it's easier to spin up the rpm to clear jumps or keeping the quad on a perfect pace through rhythm sections. Breaking loose the tires is even easier now, and sending the quad into controlled power slides or even throwing it through tight turns was done with a simple push of the throttle.
On the fast open sections where higher speeds are easier to maintain, the HRC kit performed flawlessly. The harder I pushed, the more impressive the performance became-continuing to establish its dominance over the stock TRX450R or any stock 450 for that matter. On fast, tight trails, the proximity of the ride-stopping trees made riding at the speed of light increasingly difficult. Weaving through the tightly packed trees gave me a good opportunity to try it in typical wooded cross-country racecourse conditions. Although the power is upped across the board, keeping the rpm high where the HRC kit performs at its full potential proved to be a bit more difficult while dodging trees, navigating ruts and hammering over roots and boulders. While the slower pace certainly did not leave the HRC powerplant at a disadvantage, a motor with healthy low and midrange power usually fits the start-stop style of tight woods riding. Even with the HRC kit being geared toward faster riding, it still offered a tremendous improvement over the stock 450 in all conditions when I sampled it.
Combining a headpipe, cam, intake modification, CDI alterations and jetting into one simple package designed and distributed by the manufacturer was a smart move, especially when you consider the $359.99 price tag. In our books, Honda scored a win. Achieving similar results would be nearly impossible without doubling this price. Simply adding a high-quality aftermarket exhaust alone will often amount to the average mortgage payment. For the racer on a budget, the HRC kit provides an easy alternative to maxing out the credit cards to stay competitive on the track or trail. Maybe in the future, we could see Honda provide race suspension to complement its engine mods as an option that could be purchased at your local dealer to complete the transformation into a full championship contender.