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2011 Honda CRF450R Mammoth Project Bike

Thursday, March 8, 2012

Replacing the stock 48-tooth sprocket with a 50-tooth cog helped restore acceleration performance at elevation.
Replacing the stock 48-tooth sprocket with a 50-tooth cog helped restore acceleration performance at elevation.
Few amateur motocross races carry as much prestige as Mammoth. Once a year this snowcapped mountain resort town comes alive with the sound of race engines hosting one of the most competitive and fun motorcycle racing events in the country—all at an altitude of over 8000 feet in the Sierra Nevadas.

The Mammoth Motocross races attract a diverse clientele from vets and kids to the up-and-coming rippers of tomorrow. Hoping to get our own taste of glory we made the trek with our long-term 2011 Honda CRF450R.

Regardless of class, racing Mammoth is serious business. It attracts the fastest, most talented riders from across the country. Consider this: the kid who won the Junior (novice) 450 heat race lapped faster than pro-level KTM test rider Mike Sleeter, who has the speed to qualify for a Supercross main!
When you’re racing a highly competitive event like Mammoth it’s never a good idea to just show up with a bike you’ve barely ridden, but that’s exactly what happened this time around. Having heard from other folks that the Mammoth track gets ten times rougher than Southern California’s Glen Helen we preemptively got the Honda’s suspension re-worked in hopes of making it a little easier to ride (or so we thought…).

The crew at MB1 Suspension has plenty of experience with both Showa and Kayaba suspension components. And considering owner Mike Bautista was a technician for the factory Honda Supercross and motocross race teams his outfit is a logical choice. Plus we loved the work MB1 did on the Honda CRF450R MB1 Project Bike.

MB1 did the same treatment as before fitting stiffer 0.48 kg/mm springs in the fork (stock is 0.46). The compression and rebound valve stacks were also modified for enhanced progression and greater bottoming resistance. At the rear it replaced the stock 5.4 kg/mm spring with a one level stiffer coil (5.5). The fluid characteristics of the steering damper were also tweaked to alleviate some of the steering twitchiness that the current generation Honda is known for. Each suspension piece was filled with fresh fluid to MB1’s spec. As usual work was done quickly and  turnaround time was only a couple of days.
LeoVince pipes have a carbon fiber heat shield which helps prevent the riders boots  pants  or knee braces from burning on a hot pipe.
LeoVince exhausts feature exquisite build quality. They also make good power without creating excessive noise.
LeoVince exhausts feature exquisite build quality. They also make good power without creating excessive noise.

It’s common knowledge that extreme elevation zaps power. So to try and regain some of those lost horses we bolted on a Leo Vince X3 Race Exhaust System. This pipe replaces the stock set-up and is not only lighter but boosts the powerband throughout the rev range. Since the Honda is fuel-injected it automatically compensates the fuel/air mixture so it runs flawlessly regardless of elevation. Noise pollution is a serious issue these days but the Leo muffler maintains the same decibel reading as the stock set-up. Another feature we’re particularly fond off is the carbon fiber heat shield on the head pipe which prevents your pants, boots, and knee braces from melting while racing.

Since Pirelli sponsors the races and provides trackside tire support it was an obvious choice when it came to choosing tires. Based on our test rider, Frankie Garcia’s, experience the year before we chose to run the Pirelli MX eXTRa Medium-Soft to Hard Front Tire and Pirelli MX eXTRa Medium-Soft to Hard Rear Tire.

Lastly, to make sure we looked the part we ordered a set of Dirt Digits Honda M10 Preprinted Backgrounds that come with the event’s latest big sponsor, Monster Energy. We prefer Dirt Digits backgrounds because it has the ability to print and ship quickly, plus they fit well and are simple to install.

Preparation is key in racing and while we spent all of our time getting our bike dialed-in we failed to do what is without a doubt the most important aspect of pre-race preparation: riding. As ridiculous this sounds, due to time constraints we didn’t have the opportunity to spin any laps on the bike prior to Friday practice. In fact we forgot to even set the sag until we showed up that afternoon.

From the moment I pulled on track I felt uneasy. The combination of riding a unfamiliar bike, the barrage of ripping fast riders bombing past me like I was chained to a fence pole, not to mention the Glen Helen Thursday afternoon rough track condition had me wincing and cursing for being so ill-prepared.

With so many thoughts racing through my head it was hard to focus on anything but not getting run over. So instead of worrying about how uncomfortable I felt I tried to learn the track and understand how the motorcycle reacted beneath me. The suspension felt stiff which is typical immediately following a full rebuild. The rigid ride quality was only exacerbated by the gigantic bumps all over the track. After eating mouthfuls of roost I veered off track to regroup. I started off by re-checking sag but it was right where it needed to be (105mm) so I assumed it was me just riding like a Sally. So I fired up my bike and ate more roost. 

Mammoth features a long uphill start that necessitates the use of first gear.
As we came to learn competition is stiff at Mammoth. So if youre going to invest the resources you best come prepared.
(Above) Mammoth features a long uphill start that necessitates the use of first gear. (Below) As we came to learn competition is stiff at Mammoth. So if you’re going to invest the resources you best come prepared.
Track prep and rest have the ability to mask the previous day’s problems and things felt more promising during the first and only practice on the freshly groomed track before racing started Sunday. But considering the stiff level of competition I knew it was going to be a tall order to make it into the main (each of the two five lap Junior heat races take only 12 riders with the remaining 24 or so left to duke it out in Last Chance Qualifier (LCQ) for only eight spots). 

It’s luck of the draw when it comes to gate pick in the heat races. And if there were any one track on earth that demands a optimum starting spot it’s Mammoth. I ended up on the far right side of the track which is just about the worst place you can be considering the distance between it and the left-hand Turn 1. 

Due to the elevation and Mammoth’s notoriously long uphill start straightaway most opt to launch in first gear. Replacing the standard rear sprocket (48) with a 50-tooth cog helped restore acceleration performance, kept the engine from bogging and generally made the bike easier to launch. Even if you get a good initial jump since there is more distance to cover from the righthand side of the track it’s going to be tough to holeshot the inside guys into the first turn. As expected I got shuffled back on the right side--pummeled with roost--and was toward the tail end of the group as we weaved through the first series of tree-lined turns and funneled toward the steep and narrow downhill.

Blame it on raging teenage hormones, or, the pin-it to win-it mentality of some young racers, it was almost a sure bet that there would be a huge pile-up at the bottom of the hill (Turn 4) but this time everyone managed to remain rubber side down. Since the racetrack is so narrow and hard to pass, not to forget the race is only five laps long, the level of intensity is through the roof. Everyone is ramming into one another and if you’re timid or hesitate for even a split second the guys behind you won’t think twice about knocking you over to steal a position (remember only 12 out of 40 riders transfer directly into the main).
Since the ground is rock hard (you’re racing on a mountain) it’s impossible to rip the soil so all the bumps from the prior days surface quickly once the thin layer of sand has been blown out from spinning rear tires. As adrenaline subsided the less forgiving action of the suspension took it’s toll and I was doing everything I could just to hang on. On the straights I would grab a gear, squeeze the bike, and just pin the throttle while scouting for the smoothest, least body energy-zapping trajectory as possible. In the corners I would flail around trying not to brake so much that I would lose all momentum and and get squirrely through the turn. I ended up finishing toward the back of the field having been able to steal a couple spots from guys who had fallen over.
While were sold on the quality of MB1s suspension work  we failed to do any riding on it before hand so it wasnt set-up optimally come race time.
The Pirelli tires work well on Mammoths unique terrain which is a mix of hard pack  sand and rocks.
(Above) While we’re sold on the quality of MB1’s suspension work, we failed to do any riding on it before hand so it wasn’t set-up optimally come race time. (Below) The Pirelli tires work well on Mammoth’s unique terrain which is a mix of hard pack, sand and rocks.

Considering how much I floundered in the first heat I knew it was going to take an act of God to finish inside the top-five in the LCQ. Still having had paid the entry fees, not to mention spent a few late nights wrenching on my bike, then making the 300-plus mile commute from Southern California, I was going to give it a shot. A poor heat race result equated to a poor gate pick and I again was slotted on the far right side of the starting gate. Somehow I managed a better start this time around by hugging the far right-hand edge of the track where the rolling acceleration whoops weren’t quite as large. The group funneled into the first turn through the trees and just as I was about to plunge down the hill a guy crashed and collected a couple of others, myself included. I got up as quick as I could, bump started the engine down and proceeded to run around in last place – not the way I had imagined the weekend would end.

So what did I learn? First off, Mammoth is about as real as motorcycle racing gets. It’s the proving ground for young up-and-comers looking to be the next big thing in motocross. And if you decide to invest the resources and make the trek you best be prepared – like really prepared. That means it’s better to race a bike that you’re familiar with rather than show up with a unproven set-up. While the modifications we made to the Honda have the ability to boost the bike’s performance they’re only as good as the time invested in practice/set-up so  you’re comfortable when it’s go time. Thankfully, there’s always next year...
Honda CRF450R Mammoth Photos
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Honda CRF450R Mammoth Parts List
Dirt Digits
M10 Backgrounds: $64.95
LeoVince USA
Leo Vince X3 Race Exhaust System: $1169.00
MB1 Suspension
Front Fork Revalve and Service: $195
Rear Shock Revalve and Service: $195
(2) MB1 Fork Oil 5WT: $59.98
MB1 Shock Oil: $29.99
0.48 kg/mm Fork Springs: $124.99
KYB 48mm Fork Oil Seals: $39.98
MB1 Oil Locks: $54.99
Pressure Spring: $49.99
Shock Nut: $5.95
MB1 Shock Oil Seal 16mm: $25.99
Shock Lowering Washer: $19.99
Pirelli MX eXTRa Medium-Soft to Hard Front Tire: $64.99
Pirelli MX eXTRa Medium-Soft to Hard Rear Tire: $76.99
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motousa_adam   March 13, 2012 12:35 AM
thanks for the positive feedback:) you can pickup used CRF450Rs really cheap right now I recommend a 2007-2008 or 2011-2012... those are the best models...adam
jamby7   March 9, 2012 10:12 AM
Great Post Adam! I love reading stories from guys who ride and race for the LOVE of the sport, even if they aren't the most competitive! I'm sure you would've done much better with more practice and prep on that bike. What's you're overall feeling on buying a used CRF450 to race just for the fun of it?