Bike: 2008 Honda CRF450
Location: Glen Helen Raceway
Date: May 29, 2014
Photographer: John Basher
Camera: Canon 1D Mark III
Lens: 300mm f/2.8 IS-2
Focal length: 300mm
Exposure: 1/1250 sec.
MXA VIDEO: “OLD COUNTRY” AT MTF
QUOTE OF THE WEEK: JUSTIN BOGLE
Click here to read the interview.
JOHN’S GARAGE: YAMAHA YZ125 BUILD
This is the third straight year I built a Yamaha YZ125 project bike. The first year was a learning experience. Up until that time I didn’t pay much attention to 125cc two-strokes. I frequently raced, so bikes like the Kawasaki KX450F and Yamaha YZ250F usually accompanied me to the track. However, I had a few kids and put racing on the back-burner. By happenstance I jumped on a YZ125 to race the 125 Two-Stroke Adult class at REM with my buddy, Scott “Whisky” Williams, just for fun. It was love at first crack of the throttle (the YZ125, not my feelings toward Scott).
Why do I love the Yamaha YZ125? Let me count the ways.
(1) It’s bulletproof. I haven’t encountered many mechanical issues with the bike, aside from normal wear and tear.
(2) It has a six-speed transmission. Rarely do I use first or sixth gear, but the close-ratio transmission means I always have a bit of leeway if I flub a berm. For that reason the YZ125 is very forgiving.
(3) It has awesome suspension, notably on the 2006 and newer model. The Kayaba SSS components are the perfect blend of performance and bottoming resistance. I’ve tested many bikes that are good in one area but sacrifice in another part of the track. Not the SSS-equipped YZ125.
(4) It’s a breeze to work on. I can reach the piston by only using a few metric wrenches, Philips head screwdriver, and a couple Allen wrenches. The parts are also relatively inexpensive to replace (unless you go the expensive route like I did).
(5) It doesn’t do anything glaringly wrong. That says a lot about a bike, given that you often have to give to get. The suspension is great, the engine is solid from the bottom to top, and handling is neutral. It’s baby bear’s porridge, plain and simple.
Having said those things, I unloaded every idea I could possibly think of into my 2005 Yamaha YZ125. Why? I suppose it’s a sickness. If some changes are good, then more must be better, right? We’ll see. As overboard as I did go, it could have been a whole lot worse. I almost pulled the trigger on titanium hardware and, if CRM in Italy ever emailed back about purchasing a carbon fiber fuel tank, I would have been in way over my head. However, I’m a believer that things work out as they’re supposed to. As is, my YZ125 has Kayaba PSF-1 A-Kit suspension, a full Hinson Billetproof clutch, X-Trig adjustable offset triple clamps, Dubya wheels with D.I.D. DirtStar rims and Talon magnesium hubs, Pro Circuit Works pipe with carbon fiber silencer, Pro Pegs titanium footpegs (with titanium pivot pins), ICW reinforced radiators, Moto-Master brakes, LightSpeed carbon fiber parts, a full Cycra Racing restyled plastics kit and DeCal Works semi-custom graphics. Like I said, the build was far beyond the realm of normal. I’m not ashamed, though. For the past 12 years I’ve learned the project bike craft and wanted to showcase my knowledge by unleashing a bike that would be admired and desired by many. Hopefully you’re in that club.
Want to know some interesting tidbits of information I learned while building the 2005 Yamaha YZ125 project bike? Read on.
(1) The Kayaba PSF-1 A-Kit air forks use the newer fork lugs, meaning that I had to get different front wheel spacers and a shorter axle to fit the forks. I also used Cycra front fork guards. I’m a nut (no pun intended) about keeping extra nuts and bolts leftover from old project bikes. Fortunately I had six bolts that fit perfectly in the fork guard holes. You’ll probably want to know that a different front brake hanger was also necessary. Moto-Master took care of that.
(2) X-Trig makes a crazy set of ROCS triple clamps. I’ve ridden with them before, but never installed a set. The technology is unbelievable. I swear a group of NASA scientists created the blueprints for the ROCS system. The YZ125 clamps have an adjustable offset–22mm or 25mm–and use four different torque settings for installation. I like that X-Trig includes bar mount risers. I didn’t use them, but I like how they were included. I’m 6’1” when my lower back allows me to stand up straight, but I’m not exactly Andre the Giant. Hence, the standard bar mount height works well.
(3) I could have begged a newer airbox out of Yamaha–and they likely would have obliged, given they shipped me a new subframe–but I don’t mind the look of the older airbox. The newer integrated airbox/side panel design doesn’t look as racy to me as being able to see the midpipe and more of the subframe. Maybe that makes me old school.
(4) Don’t think for one second that I completely overhauled the engine. I didn’t. I’ve tested YZ144’s before, and I didn’t like how the big-bore changed the powerband. To me, going oversize turned the stock stud into a dud. Instead I installed a Vertex top-end kit and focused on what I knew would work. Which brings me to…
(5) I’ve had really good results with the Boyesen RAD Valve on the YZ125. It sharpens throttle response and increases power across the board. For good measure I threw in a Boyesen Power X-Wing, which is said to better direct airflow into the carburetor. Those changes, combined with a Pro Circuit Works pipe and Shortly carbon fiber silencer, turns the YZ125 into a rocket ship.
(6) Laugh if you want, but I went up one tooth on the rear sprocket. MXA gets a bad rap for always insisting on gearing test bikes down. That’s not true. Manufacturers have begun embracing the idea that motocross riders–not desert dogs–are buying motocross bikes. Hence, manufacturers are now gearing their bikes (there I go again with the puns) toward moto-minded riders. As for why I went up to a 49-tooth rear sprocket, it makes the shift from second to third to fourth gear much easier. I’m too slow and too heavy to keep the power on the pipe otherwise.
Tomorrow I’ll take the bike on her maiden voyage at ClubMX Practice Facility. It will be ridden by Ben Graves (ClubMX Practice Facility manager), Jessica Patterson (multi-time Women’s National Champion), Allan Brown (former Moto XXX team owner and Star Racing team manager) and myself. Look for an opinion piece on the bike in next week’s Mid-Week Report.
PHOTO OF THE WEEK: REMEMBER WHEN?
DID YOU KNOW? PRO CIRCUIT JETTING SPECS
Click here to view Pro Circuit’s jetting catalogue.
CHASING THE DREAM: EPISODE FOUR
Check out James Stewart’s digs
BLAST FROM THE PAST: THE MIGHTY SWEDE
The classic photo above shows Hallman soaring through the air on his Husqvarna 250 Cross. Notice the pudding bowl helmet, crude motocross gloves, all-leather pants and lack of eye protection. You can read about Torsten Hallman’s exploits and impact on motocross by clicking here.
THE SAND BOX: PIERCE BROWN
FASTEST OF THE FAST: AMA NATIONALS
An ongoing list of the top qualifiers and holeshot winners from each round of the 2016 Lucas Oil AMA 250/450 Nationals.