Tested: 2015 Honda CRF450R Yoshimura Project Bike 2

Over the past few years, the Honda CRF450R has received mixed reviews from both racers and critics. This is mostly due to its smaller chassis, handling traits, and mellow powerplant. Personally, I hadn't quite come to grips with the current CRF450R, even though I'm a smaller individual that quite enjoys the light weight and size of the bike. I had thrown a few parts at it to try and boost performance during an earlier project, but even then I still had areas I wanted to improve. My main hopes were to get a bit better front end feel, and add a lot more grunt to the engine, while still maintaining its easy-to-ride powerband.

First Impressions

As mentioned above, this project wasn't the first go around for our 2015 CRF450R. To hear what we did on our first round of upgrades, check out the video/article here. First off, we'd added a Yoshimura ST-R camshaft and RS-9 Carbon/Titanium exhaust system, so we continued down that route and asked the Yoshimura crew what else they could do to get us a bit more grunt out of the engine. They suggested that we could make some large power gains with just some head work and additional engine mapping. After we handed over our engine, the Yoshimura crew went to work with a port and polish job, the addition of high performance valve seats, and boosting compression by trimming the height of the cylinder head. Yoshimura has had great luck with Honda's stock piston, rather than replacing it with an aftermarket piston to gain the desired compression. They also pulled the cases apart to give the transmission some love with their Isotropic Surface Finishing (ISF) process. This allows for smoother shifting and reduced friction, which equates to more power. Once the components had been massaged, Yoshimura reassembled the engine, added a Rekluse Torque Drive clutch, and dropped in the same Yoshimura cam that we'd been running for the past few months.

The motor package Yoshimura set us up with has an option for a Vortex ignition, which they developed with Jamie Ellis from Twisted Development Racing. Jamie is a very experienced engine builder and electronics guru, who most recently developed Rockstar Racing's engines when they were on Suzukis, before setting off to start his own business. A big part of Jamie's electronics experience comes with the Vortex ignitions, which he is now development partner of their's here in the USA. Since we were dealing with a higher compression engine and a custom ignition, we of course went for some more potent fuel with VP's MR-Pro6. (Why MR-Pro6? It's VP's pro level legal fuel and the plan was to send this bike to the first few nationals. Sadly, things don't always work to plan and the bike only made it through Hangtown, as the rider had a minor injury). The Vortex box that comes with the package has a total of ten maps to choose from at any time, five for pump gas and five to run with MR-Pro6. The Vortex also allowed them to throw in a bonus, by taking Honda's handlebar-mounted map switch and turning it into a launch control system. This launch control was based off the system that was run with the Rockstar Racing team, which has a fixed max RPM (10,800 in this case). That means you just hold the throttle wide-open, drop the clutch, and the electronics do the rest.

Once the engine was back in the chassis, it went to the dyno for a test and the charts showed (at least on paper) what the efforts had produced. Considering the bike actually had very little mods internally (just the head work, mild cam, ISF transmission, exhaust system and a Rekluse clutch), plus the addition of the Vortex ignition and VP fuel, I was surprised to see a near ten horsepower jump over the stock bike on the same dyno! Of course the biggest question was, would it be easy to ride, or a handful?

Before I set off to the track, there were a few other things to get ready on the bike. A few months prior, we'd had Race Tech go through the suspension, adding a gold valve kit front and rear, along with their 18mm shock shaft kit. Considering that the current setting was pretty spot-on, we just had them run through the set and freshen them up. To aid the handling side, Adrian from Ride Engineering suggested we tried the 21mm offset triple clamps that he had for the CRF450R (stock is 20mm), with the goal of eliminating a lack of traction I felt on the entrance of corners and creating a more consistent feel through longer corners.

As for the durability side of things, I added some hard parts from Works Connection, such as their radiator braces, plus a Powerflow plastic kit and skidplate from Cycra. To help keep our stout engine cool, I kept things somewhat simple by adding some high-quality coolant from Engine Ice, along with a radiator cap with a higher blow-off pressure. I also wanted to beef up the wheels, but without adding too much weight. To do so, I had some DID ST-X wheels laced up by Colin at Faster USA to a set of his billet machined hubs. While the rims are heavier than stock, the hubs are actually lighter than their original counterparts, making the transition a wash. Plus, they look awesome.

On the Track

My first trip to the track was a bit interesting, as I was curious if the bump in power was going to be what I was hoping for, or if it would be too much. Right off the bat, I was confident rolling on the track because Jamie's work was really shining through. The bike starts just as easy as stock and the throttle response was crisp and immediate, but not too jumpy and unsettling. As I rolled around on my warmup lap and seat bounced a few of the smaller jumps, I noticed that the way it produced power was still fairly similar to stock, but it didn't bark and snap out from under me. It mimicked the stock engine by rolling on progressively, but at a much more extreme rate, especially as it gets into the mid-range.

One of my biggest struggles with the stock bike was the gearing vs power. On the stock bike, I always felt like I had to go down to first gear in tight sections. I'd experimented with adding two teeth to the rear sprocket in an attempt to bring the bike up to second gear in tight corners and get into third earlier. But I found it doesn't really work too well with the lack of power in the stock engine, as it just didn't have enough snap to get up and going like you'd expect from a 450. With increased response and torque from the Yoshimura engine, going up two teeth in the rear now provided the grunt to get me over any obstacle I needed with extra to spare if things went a little wrong. I was also quite pleased at how big of a difference having proper engine mapping made, as the bike never coughed, sputtered, or had any delay no matter where I was in the rev range, whether I was leaving corners or between jumps.

Even better was the ability to actually rev this bike out, because the stock bike in either second or third gear would run out of pull at the most inopportune times. But with the added power, I could just hang it out a bit deeper into corners or obstacles, without the worry of the bike nosing over and running out of power. This all added in extremely well to the Honda's lightweight chassis, as you can treat the bike even more like a 250F, since you're not short shifting it to get over jumps and keep it moving. If I did feel the need to shift though, the ISF treated transmission made a huge difference under heavy loads. I've never been the best at giving the clutch a little tap while pinned, which made this quite important to me, especially when approaching a few larger jumps when a clean shift is all too important.

If you want a better idea of how much power this bike is putting out, I have a pretty good example. Right after the bike was finished, we lent it to a local pro, Johnny Jelderda, to put it through its paces at the 2015 Hangtown National. Due to a minor wrist injury, Johnny wasn't able to perform at his best but he was able to send this bad boy over the Fly 150 (150ft triple step-up) at Hangtown one every SINGLE lap. Being the only rider other than Eli Tomac to do so.

The other added plus to our gearing change came with starts. Due to the launch control and the big boost on power, I did some practice starts and realized I could replicate some "Short-esque" third gear holeshots. To test my theory out, I grabbed some riding buddies and had them lineup up with me on the gate. I would just press the button, click the bike into third gear, hold it wide open, and slide the clutch out. While the other 450s could get a small jump on me right out of the gate, I was amazed how much ground I'd gain and how far I'd pull away when they made the shift to third, and I just kept pulling through the range.

As for the handling side of things, I worked with Rob from Race Tech a few months back to settle out the Honda and increase the hold up of the PSF2 forks, while keeping some initial plushness and comfort. Overall, the Race Tech crew gave me a set of suspension with a ton of options, as their 18mm shock shaft kit adds a low-speed rebound adjustment in the clevis to add to the massive amount of options that the forks offer as well. In stock trim, the shock adjusters have a wide range, but don't offer a ton of change throughout the range. Adding the 18mm shaft gives the shock a larger charge as it passes through the stroke, making changes much more noticeable as the oil passes through the compression adjuster. While updating the bike, I wanted to increase the offset slightly, as I like the feel it offers on the CRF450R. Ride Engineering's 21mm clamps added a bit more consistency in longer corners, while also making the front end feel a bit more planted and helped eliminate a bit of front-end knifing I was feeling as I entered high-speed corners.

The Last Word

I've been on the fence with Honda's CRF450R the past few years, and honestly haven't ridden one in the latest generation that made me want to take it out day-after-day. The fact that I spent a few weeks straight riding this one may give a clue as to what I thought of it. I had an ear-to-ear grin from the first couple laps and can honestly say if the stock Honda had this kind of power output, or something close to this, it would have taken my number one spot in the the Vital MX 2015 450 shootout. It's that good. The fact that the engine has the same easy-to-ride characteristic of the stocker but with a ton more grunt everywhere, it was hard not to like it. Where the stocker had me looking for more at least a few times a lap, I found myself pushing harder and harder because I had the power when I needed it, but could easily control it without wearing myself out. Even better yet is the fact that the engine still has a stock bottom end, piston and valve train, meaning long-term durability isn't really a factor or question. While I knew I could make the bike handle the way I wanted with the help of Race Tech and Ride Engineering, the crew from Yoshimura really knocked it out of the park on this build by filling the biggest needs I had with this bike. If you have a CRF450R that needs some more juice, Yoshimura has a ton of options for any budget that will help the Honda really shine like it should.

2015 Honda CRF450R Yoshimura Project Bike Features:

Services provided by Yoshimura - (Yoshimura-RD.com / 909 628-4722)

 $4269.29 (all labor and parts/not including complete Yoshimura exhaust system):

• Optimize port profile for Stage 3 specification.
• Machine cylinder head surface for increased compression.
• Install high-performance valve seats.
• Install new valves, valve springs, top retainers, and valve cotters.
• Install Yoshimura ST-R camshaft, degree to specification.
• Piston, ring set and pin replacement.
• Inspect crankshaft, transmission assembly.
• REM / ISF transmission treatment.
• Install complete Rekluse clutch.
• Blueprint complete bottom end and assemble.
• Pro Taper wireless hour meter (free with service).
• Optional exhaust, complete Yoshimura Carbon/Titanium system $1495.00.

Twisted Development Racing - (TD-Racing.com / 337-781-6400)

• Development services in co-junction with Yoshimura.
• US dealer and technical partner of Vortex ignitions.

Ride Engineering - (Ride-Engineering.com / 800-805-1516):

• Honda CRF450R black 21mm triple clamps ($499.90).
• Fourth generation over-sized one piece bar mount ($99.95).

MotoStuff - (MotoStuff.com / 503-830-6433):

• 280mm Blade Oversized Oversized Front Kit ($318.00).

Cycra - (CycraRacing.com / 603-298-6646):

• Complete powerflow body kit ($199.95).
• Full armor skiplate ($98.95).

Factory Effex - (FactoryEffex.com / 800-866-0709):

• DX1 custom graphics - Apex series.

Engine Ice - (EngineIce.com):

• Engine Ice coolant.

Motorex - (MotorexUSA.com / 763-417-1377):

• Cross Power 4T 5w/40 oil.

Pirelli - (Pirelli.com / 800-747-3554):

• Scorpion MX32 80/100-21 front tire.
• Scorpion MX32 120/80-19 rear tire.

Works Connection - (WorksConnection.com / 530-642-9488):

• Elite clutch perch ($155.85).
• Factory edition radiator braces ($129.95).
• Pro launch device ($109.95).
• Forged brake lever ($37.95).
• Factory 4 stand ($119.95).

Pro Taper - (ProTaper.com / 951-736-5369):

• Fuzion handlebar ($129.99).
• Half-waffle grips ($12.99).
• 13T front sprocket ($25.99).
• 49T rear sprocket ($64.95).
• PT520MX chain ($84.95).

VP Racing - (VPRacingFuels.com / 210-635-7744):

• 5 gallons MR-Pro6HT fuel.

No Toil - (NoToil.com / 877-668-6451):

• Super Flo kit ($49.95).

MotoSeat - (MotoSeat.com / 951-677-8325):

• Custom ribbed seat cover ($64.95).

REC MX (RECMX.com):

• Billet oil filter cover ($54.95).