By Brian Chamberlain

We kicked the dirt bike up a notch in phase 2

Hello, mini moto junkies, and welcome back for Phase 2 of our Honda CRF150R Expert project bike. In case you missed it, we did a full review of the new-for-2012 Honda mini thumper a few months back and came away very impressed with the changes made to the 150R. Although the bike was very good in stock trim, we couldn’t help wanting to make it even better and have since been embellishing the little ripper with some of the coolest aftermarket products available.

In Part 1 of the project, we focused on the ergonomics and improving the durability of the parts most susceptible in a crash. We started things off with a set of ProTaper 7/8” SE bars and also included a ProTaper Aluminum Throttle Tube. To complement our new bars, we then added a set of ProTaper MX Pillow Top Lite Grips. Finishing off the hand controls, and ensuring we wouldn’t have to deal with any broken levers, we threw on a set of Sunline V1 MDX unbreakable levers and also included Sunline’s SL-4 clutch assembly for easy on-the-fly adjustment. To complete our first batch of upgrades we moved our attention to the foot controls. While the stock pegs were ok, we wanted a little larger platform and more grip. ProTaper helped us out once again with a set of their S.P.I. 2.3 platform pegs. For more information and our opinions on these products, be sure to read the full 2012 Honda CRF150RB Project Part 1.

With the bike controls up to par, we are now ready to focus on the bike’s drive components and getting the power to the ground. Most of the components in this phase are high-wear items that needed to be replaced after a couple months of testing anyway, but also benefit the performance of the bike and are a definite improvement over the stock parts.

Kenda K775 Washougal Intermediate Front Tire: $76.95
Kenda K775 Washougal Intermediate Rear Tire: $74.95

Residing in the Northwest, we couldn’t help but try out a tire named after one of our favorite tracks. Washougal is well known for its tricky and ever-changing dirt. A morning practice session starts off with deep loam, and often mud, but by afternoon the track dries out and packs down into a very hard and slippery surface. Since we were testing at a wide variety of tracks that range from sand to hard-pack, the K775 sounded like the perfect choice.

After a couple months of use, we came away very impressed with this intermediate terrain tire. We found that the Kenda K775 Washougal Intermediate front and rear tires hook up extremely well in the soft terrain, whether its sand or mud, yet still perform well on hard pack. Our mini test pilot reports increased grip, especially from the front, which has really inspired a lot more confidence in the corners. Most impressive, for the cost-conscious racer, is the long life of the tires. We have logged extensive hours on the Kendas and they show very minimal wear.

ProTaper 420 Rear Sprocket: $64.95

Stock gearing on our 150 Expert was a little tall for most of the tracks we were riding and could be improved by adding a tooth to the rear. Since the stock steel sprocket was starting to show some wear, we opted to replace it with a ProTaper aluminum sprocket. The added tooth made our CRF a little quicker out of the corners and still has plenty gearing left up top for those high-speed sections.

The ProTaper rear sprocket is CNC-machined from 7075-T6 heat-treated aluminum and shaves serious weight compared to the steel cog it replaces. ProTaper claims its proprietary mud groove design results in 44% more tooth surface area, which increases the life of the sprocket dramatically. It appears the sprocket is living up to this claim, as our sprocket is showing very little wear after months of use. ProTaper offers the sprockets in either a black or magnesium anodized finish.

ProTaper 420MX Chain: $34.95

With a new, bigger sprocket needed in the rear and our stock chain stretched out quite a bit, upgrading the drive chain was a no-brainer. We opted to stick with ProTaper to maximize compatibility by purchasing their 420MX gold series chain. The gold series chain is very lightweight but also maintains a 5000-pound tensile strength due to its premium chromoly construction. While you can improve chain life with an O-ring chain, we opted to stick with the traditional to reduce drag and keep our little CRF producing as many ponies as possible. Our ProTaper chain stretched out a bit at first but has now settled in and very rarely needs adjusting.

ProTaper 420 Front Countershaft Sprocket: $25.95

While we didn’t require any gearing change up front, it’s always a good idea to use a new sprocket when replacing the chain. Again, to keep things consistent, we again chose ProTaper in the stock 15T size. While there is not a lot of difference in countershaft sprockets, ProTaper does use drilled holes to keep the weight down and, like the rear, utilizes self-cleaning mud grooves to prevent dirt build-up. Also, ProTaper claims a special coating over the cro-moly steel helps retain strength and adds life.

Hammerhead Designs, Inc. Case Saver: $34.95

After installing a new chain and sprockets, the last thing you want to do is compromise the life of your new purchase. Conditions can get pretty wet up here in the Northwest, and the stock countershaft guard easily packs full of mud, causing a lot of unwanted wear on the chain. Simply removing the stock case guard would eliminate the potential for packing in mud, but leaves the case extremely vulnerable should you ever throw a chain.

To solve this problem we opted to install a Hammerhead Designs case saver. The case guard is CNC-machined from 6061-T6 billet aluminum and provides an extremely light yet very strong guard just in front of the countershaft sprocket. The Hammerhead guard is designed only to protect the engine case, exposing the countershaft sprocket completely by eliminating any type of side coverage. This is great for eliminating mud build up, but be careful to keep your fingers away from this area when the bike is running, as you are now vulnerable to loosing a digit if your fingers ever get too close. The Hammerhead Case Saver is extremely easy to install and, for our Honda, was available in anodized red.

CV4 Radiator Hose Kit: $86.99

Our final upgrade for phase two was a CV4 Radiator Hose Kit. With a wide assortment of colors, the CV4 kit definitely adds some cool factor to your ride, but at the same time, they also provide some performance improvements. The CV4 hoses are constructed of pure silicone with polyester reinforcement. They are able to withstand temperatures up to 420 degrees and, unlike OEM hoses, resist UV deterioration. They also utilize a smoother inside diameter, which allows for increased coolant flow.

The CV4 hoses come in enough colors to match any bike, and they eliminate the Y connectors on some models. We found installation to be simple, and the length and bends of our CV4 hoses matched up perfectly with the stock hoses.

We experience a tight seal at all of the connections and have had no problems with leaks, punctures or any color fading.


That wraps up the upgrades for Phase 2 of our CRF150R project bike. The high-wear parts we focused on for this stage are now fresh and ready for more testing abuse. Our little CRF continues to run flawlessly, and we have yet to experience any mechanical trouble. The 150R Expert is a competent race bike that has been a blast to ride. It also helps get our young rider familiar with the power characteristics of a 4-stroke. He’ll be jumping to the 250F class eventually, and the Honda has been a good way to introduce the Thumper breed. Now that the weather is turning around and the CRF is better than ever, we’ll be out pounding even more laps.

For more information or to purchase these products, or other parts and accessories for the 2012 Honda CRF150R Expert, visit