James Stewart II

Jedi Supercross flow.

TR

MOTO - The Movie

www.moto-themovie.com

FYi YZ250F - anatomy of a race bike

I think one of the things I like about building bikes is that it's essentially product development. You are finding ways to improve every aspect of performance while tuning the bike to your specific riding style, and track conditions..

The first, single most important tuning mod to a motocross bike is to have the suspension re-sprung for your specific weight, and re-valved for your track conditions and/or handling preferences. Getting your suspension set up right makes all the difference in your confidence level on the track. We use Enzo racing for our suspension work.

I love the playfulness of a 250cc, although I find the stock 34hp to come up a little short. For me, the sweet spot in the go-department is more like 42hp. To get there we installed a WMI prepared race head, with a high compression piston and more aggressive cams. This raises the compression to 14:1 and increases the redline to 13,600 rpm. Throttle response is snappier, it makes more power through the entire rev-range, and loves to over-rev (which the stock YZ motor certainly does not).

To match the performance gains in the race head, we use the FMF megabomb titanium header, and 4.1 carbon fiber muffler. It allows the bike to breath better and make more power.

To make it quicker, we went with a 50T Renthal rear sprocket, which lowers the gear ratio slightly to match the top speed on the fastest part of our track. You don't want the bike geared taller than the track's top speed, as the lower the bike is geared, the quicker it can accelerate to it's top speed.

To make it stop faster, we installed an oversized 270mm front brake rotor. This provides a lot more stopping power with less effort. You can literally stand this bike on the front wheel with one finger while braking. Being able to drop anchor when needed, really increases your confidence when you're comin' in too hot!

That's the short-and-sweet as far as the tuning is concerned. Now let's look at the rider's controls...

A lap timer is integrated into the handlebar pad. You can time your motos and/or record individual lap times that you can review after each moto. This is good info if you are working on your endurance, or your speed (or both). The lower gauge is the hour meter for the motor, so you can keep track of your maintenance intervals.

Your left hand is controlling the clutch. The green button trips the lap timer. The tiny red lever underneath is the 'hot-start' lever that helps you get the bike started. And the big red button that says Engine Stop, ...stops the engine.

Your right hand is controlling the throttle and the front brake. The yellow switch controls the Vortex ignition, which allows you to flip between 2 of 10 possible different ignition maps. You can switch on the fly while you are riding, and actually change the power curve of the motor. I personally like the 'high compression map #5' most of the time - it just goes ballistic at the top of the rev range. Although if you're tired, or the track is slick, you can switch to the mellower map#1.

Your left foot controls the transmission. Most bikes have a 5-speed gearbox, with a 1 down, four up shift pattern.

Your right foot controls the rear brake.

You get everything right, and the result becomes greater than the sum of the parts. A -really- well set up bike is just magic. It's an extension of your body, making you feel like superman (or wonder woman?).
TR

Millville 2009 Pro National

Moto GP of Sweden

Check out the W's opening moto!

Swedish moto-bad-bitches...

The finish line jump looks super fun.

TR

2010 YZ250F

Typical. No sooner than you break-in your new bike, and they're already announcing the new & improved model. Next year's bike gets a new frame, and some changes to the motor. Although EFI is not included, which is just fine with me.

TR

2009 Yamaha YZ250F

It's official. My new whip is not a Honda... For those that don't know, it's a pretty big deal to 'change teams'. My first bike was a Honda, and my second, and my third, and my forth & fifth, plus my lawn mower & weed-eater. Everything is red. As it always has been. Until now.

Right out of the box, this bike rips. Stoked to be back on a 250cc.

I'll post a tuning and set up update soon.
TR

James Stewart

JS7 is currently the fastest motocross racer in the world.

Michael Jordan, Tiger Woods, James Stewart  ...he's that good.

TR

James Stewart - Dancin' Machine

James Stewart - Segway Supercross

Last roost...

..before departing for TOKYO.

TR

mega moto.

Meet Shawn Maffenbeier of Team PerformX. We rode with Shawn down in SoCal(team burrito) in early April, and this kid has skills..

Shawn is 16 and racing pro in the Canadian Nationals. He dominated at the G.R.R.C. race last weekend. At home his dad makes him line up at the starting gate facing backwards, just to give the other guys a chance.

Shawn is super focused, and will likely go far in this sport.

Team PerformX:

Shawn Maffenbeier, Warren Barrow, and Todd Schumlick.

Coolest guys in the bathroom for sure.

TR

micro moto.

We attended a race last Sunday at G.R.R.C. (our local motocross track in Pemberton).

There is nothing like the roar.. errr, i mean buzz, of half a dozen micro motocrosser's, giv'ner for the holeshot!! These guys are 3-6 yrs. old. They just look for their parents to tell them what direction to go, and then just pin it! Imagine a pissed off sounding leaf blower running at redline.. or maybe a blender set to 'puree'.

Check for micro attack position. Cutest thing ever.. 

(until they turn 12 and start bagging 120ft triples).

TR

CRF450R Project update.

Ok, i've been lagging on the four-five-oh project update. The bike has actually been done for awhile, and is already broken in. This is one serious piece of motocross engineering. This is actually my second 450cc, however i've been primarily riding a 250cc for the last couple of seasons.

The red RG3 triple clamps help control deflection in the forks for more precise cornering and wheel placement.

The Honda HPSD is a steering dampening system, that allows you to 'tune' the steering characteristics to your personal preference. You can increase the dampening for increased stability or reduce dampening to improve turn-in response in corners. Honda is the only company with a system like this, so far..

The steering dampener is the little widget in the center. It articulates with the steering, and helps control the front end of the bike.

This hour meter tracks every hour the engine is running, so you can keep track of all your maintenance through the life of the bike.

Carbon fiber fork guards don't actually improve anything - they just look cool.

Titanium exhaust by FMF. Sounds good. Looks good. Adds a couple HP.

The bike handles brilliently! After five hours of track time though, I've concluded I still prefer a 250cc for a couple of reasons. The 250cc can be ridden high in the RPM's and 'on the throttle' most of the time, where as the 450cc requires pro level skills to be ridden that aggressively. Another factor is the increased crank mass of the 450. It feels like a 250 until you start to roll on the throttle in a corner (the crank mass makes the bike want to stand up in corners) and then it feels like the 'big bike' that it is. I prefer the more playful feeling 250cc for my style of riding. A 450 with 50+HP on a motocross track is serious; grab a -tiny- bit too much throttle and next thing you know you are flying 120ft on a 90ft jump. It demands respect, and requires precise throttle control at all times.

Bottom line is a 450 is 'serious' while a 250 is 'playful'. And a well ridden 250 can be as fast or faster than a 450 on some tracks. So now that i've finished the 450 project, I've decided to hit the restart button and start over with a 250!?.

Anyone interested in a race ready, mint 2009 CRF450R, contact FYI ASAP.

TR

Troy Lee Designs SE2 Helmet.

My new brain bucket.

The 2009 Speed Equipment Helmet in History Blue.

Susanna's in History Red.

TR