Torc1 Racing’s Yamaha YZ125

2005 Project Bike on a Budget

By Ryan Pursley

At Torc1 Racing we are all racers at heart and have a deep passion for the sport that goes back to when we were kids riding mini bikes. We enjoy building project bikes and we usually put together two or three project bikes each year. Last year we had a lot of fun putting together a 2003 YZ250 two-stroke and racing it at the MTA Two-Stroke National. With my son Zack just starting to get serious about riding and racing, we thought it would be fun to build him a tricked-out Yamaha YZ125. The YZ125 is a great platform to work with because there are so many aftermarket parts available for it since it has remained virtually unchanged since 2005. We had just moved Torc1 Racing to Texas and were having trouble finding a clean YZ125 in the Dallas area, so we decided to look at Craigslist in California and found a 2015 YZ125 with 27 hours on it for a great price. Our good friends at Red Label Graphics crated up the bike for us and shipped it off to Texas for the build.

When we received the bike, let's just say that it looked a lot better in pictures than it did in person. This thing was going to need some work. Our first call is always to our good friend and guru bike builder Jay Clark at jayclarkent.com. Jay has built a ton of bikes over the years for all the magazines and really knows his stuff. He has worked with us on our last couple project bikes and has done a great job on the motors for us. We shipped the motor and carburetor out to Jay and found out it was going to be a lot more work than expected. Jay said the bike had been detonating so bad with pump gas that it ruined the cylinder and the head. We decided to ship the cylinder and head off to Millennium Technologies. They re-plated the cylinder and cleaned up the head so it was like brand new. We then turned to Wrench Rabbit for their Motor in a Box Kit. This comes with everything you need from the bottom end to the top end. Piston, Rings, Rod, Crank, Gaskets, and Bearings. If you are looking to completely rebuild your motor this is the only way to go. While we had the motor apart we added a complete billet clutch and cover from Hinson Racing. Not only does the cover look good and hold up to wear better than anything we have used the clutch is bulletproof and performs amazingly. We also added a Boyesen Super Cooler to keep our Evans Coolant flowing well and a Boyesen RAD Valve to help add some horsepower to our YZ125. Moto Hose supplied the blue hoses for the radiator and carburetor. The hose kit also comes with a fuel line hose, gas cap vent hose, and radiator overflow hose. Jay also completely rebuilt and jetted the carburetor with a rebuild kit from All Balls Racing. To top off our new motor and carb rebuild we used an FMF Factory Fatty Pipe and Shorty Silencer. We also installed a Twin Air Power Flo air filter cage and filter.

Being that Torc1 Racing is based out of Texas now, we thought it would be good to feature a local Texas company to help us with the suspension. EBR Performance is based out of League City, TX and fields an Amateur Race Program that is supported by Yamaha and has won lots of National Titles. Some of the top amateur riders in the country rely on EBR for their motor and suspension needs. Josh and the crew definitely know what they are doing when it comes to the YZ 125 so we sent our suspension off to them for a complete rebuild. They went through and replaced all the internals that were showing signs of wear, replaced the seals, did their magic to the valving, and added a fresh set of springs front and rear for Zack's weight. While the suspension was out getting rebuilt we replaced all the bearings in the steering head, swing arm, and linkage with bearing kits from Pivot Works.

Now that we had the motor and suspension taken care of it was time to decide how we were going to make this bike look. Obviously, we added all the Torc1 Racing products consisting of our Showtime bend Attack Bars, Vengeance Flex Levers, Hole Shot ½ Waffle Soft Grips, Motion Brake Pedal, and Reaction Shifter. Rocky Mountain ATV helped us out with a set of Tusk Impact black wheels laced up on blue hubs. We mounted up a set Goldentyre tires to our fresh set of wheels. They set us up with the GT216AA front and GT232N rear. Sunstar provided the chain and sprockets with 13/49 gearing. We used Braking Batfly Aluminum oversized rotors for stopping power front and rear. They also look really cool! Works Connection helped us out with all the blue anodized parts for the brake reservoirs, oil fill plug, and chain blocks. They also provided some protection parts with the radiator braces and skid plate. Pro Moto Billet sent us a pair of their Fastway EVO Air Foot Pegs. These are really cool because you can adjust the height, camber, and grip of the pegs to suit your individual needs. We decided to go with a blue front and black rear theme for the bike and UFO supplied all the plastic along with a new chain slider and chain block. Red Label Graphics was able to tie everything together with a great looking graphics kit to go with our blue and black plastic. Last but not least Think Technologies finished off our build with a lightweight seat foam and grip seat cover. We were able to save 1 ½ pounds off the top of the bike by using the Think seat foam. Our complete seat with base, foam, and cover weighs considerably less than just the OEM foam. Pretty Impressive!

The bike was complete and it was time to hit the track. After two months of putting this bike together, Zack could not wait to ride it. For our initial test, we headed out to Greenville Motopark in Greenville, TX. They have amazing dirt and a good track design that lets you get up into fourth and fifth gear on certain parts of the track. The bike ended being a little rich across the board and that was probably due to the fuel we were running and the low altitude in Texas. Clark told us to go to our local airport and purchase some AV fuel. It is super clean gas with a high octane rating. Once we got the bike broken in and started leaning it out the bike was a rocket. The motor pulls strongly off the bottom end in second gear and continues to pull as you shift through third and fourth gear. The combination of the FMF Pipe, Boyesen Rad Valve, and 13/49 gearing worked great. The suspension was on point as well. Super smooth and plush on braking bumps but was able to soak up the big hits as well. EBR did a great job and you can feel why they have won so many National Championships. One other key part to point out is the Goldentyre tires. This is our first time using Goldentyre and we were very impressed with the way the tires feel on the track and how well they are wearing now that we have some time on the bike. All in all this bike was a home run. It looks like a Factory Race Bike and the performance is perfect for Zack to learn and grow with. At our first race with the bike, Zack was able to holeshot against some of the other riders on 250F's. We would like to say Thank You to everyone that helped out with this build especially Torc1 Racing, Wrench Rabbit, EBR Performance, and Transworld MX. We look forward to the next one!

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Parts List

Engine:

-Wrench Rabbit Rebuild Kit

-Vertex Piston

-Hot Rods Crank

-Cometic Gaskets

-Millennium Technologies Cylinder Re-plating

-Hinson Complete Billet Clutch System

-FMF Factory Fatty Pipe and Shorty Silencer

-Boyesen Rad Valve and Ignition Cover

-Sunstar 13T Countershaft Sprocket

-Twin Air Power Flo Filter Cage and Air Filter

-Torc1 Racing Reaction Shifter

-Works Connection Oil Fill Plug

-All Balls Carburetor Rebuild Kit

-Moto Hose Carburetor Overflow Hoses

Cooling:

-Moto Hose Radiator Hoses

-Evans Waterless Coolant

-Works Connection Radiator Braces

Brakes:

-Braking Batfly 270mm Front Rotor

-Braking Batfly OEM Replacement Rear Rotor

-Braking Brake Pads Front and Rear

-Torc1 Racing Motion Brake Pedal and Clevis

-Works Connection Brake Reservoir Caps

Chassis/Suspension:

-EBR Performance Re-Valve and Rebuild

-Pivot Works Chassis/Linkage Bearing Kits

-Works Connection Skid Plate

Wheels/Tires:

-Tusk Impact Complete Wheel Set

-Goldentyre 51R Front and 57M Rear

-Motion Pro Rim Locks and Rim Tape

-Sunstar 49T Rear Sprocket

-Works Connection Axel Blocks

Controls:

-Torc1 Racing Attack Bars RV Bend

-Torc1 Racing Vengeance Flex Levers

-Torc1 Racing Hole Shot ½ Waffle Soft Grips

-Fastway EVO Air Foot Pegs

-Works Connection Rotator Clamps

-Motion Pro Throttle

Other Accessories:

-Red Label Graphic Kit

-Think Technologies Seat Foam and Seat Cover

-UFO Plastic

-UFO Chain Slider and Chain Guide

-Works Connection Holeshot Device

To learn more about the products being used on this bike, click the links below….

Torc1 Racing: www.torc1racing.com

Wrench Rabbit: www.wrenchrabbit.com

Millennium Technologies: www.mt-llc.com

Hinson Racing: www.hinsonracing.com

FMF Racing: www.fmfracing.com

Boyesen Factory Racing: www.boyesen.com

EBR Performance: www.ebrperformance.com

Goldentyre: www.goldentyrewest.com

Sunstar: www.sunstar-mc.com

Braking: www.braking.com

MTA Distributing: www.mtadistributing.com

Moto Hose: www.moto-hose.myshopify.com

Works Connection: www.worksconnection.com

Rocky Mountain ATV: www.rockymountainatv.com

Pivot Works: www.pivotworks.com

UFO: www.ufoplasticusa.com

All Balls Racing: www.allballsracing.com

Twin Air: www.twinair.com

Motion Pro: www.motionpro.com

Red Label Graphics: www.redlabel.mx

Think Technology: www.thinktechnology.us