Posts
327
Joined
1/21/2017
Location
IN
US
Edited Date/Time
10/18/2021 8:09pm
A few months ago I was lucky enough to score a semi-rebuilt 2003 Yamaha YZ125. The previous owner replaced most, if not all of the wear parts and even had the old parts for proof. In addition he added a rebuilt 1997 YZ125 motor, which he preferred for more torque. I gotta say this motor probably has the most torque of any 125 I've ever ridden. The bike supposedly has 20 hours since the previous owner freshened it up, which I believe is true. The powdercoated frame and swingarm only had one ride when I picked the bike up.
I'm currently in the process of finishing this build with the goal of creating a fast, reliable 125 that I can use to have have fun, race, and get more seat time.
Here is where the build started. A lot of nice aftermarket parts were previously installed that I plan to keep such as the Excel Takasago rims, a fresh set of Michelin Starcross tires, Pro Taper bars and clutch perch, and a few other minor pieces.
I'm currently in the process of finishing this build with the goal of creating a fast, reliable 125 that I can use to have have fun, race, and get more seat time.
Here is where the build started. A lot of nice aftermarket parts were previously installed that I plan to keep such as the Excel Takasago rims, a fresh set of Michelin Starcross tires, Pro Taper bars and clutch perch, and a few other minor pieces.
I had ridden the bike once around our property to get a feel for it, and then raced it at MxExpress-Toledo's Two Stroke Shootout. I went into the day with little expectations as I had yet to ride it on a track, and I finished around 7th in my class. Not bad, but certainly room for improvement with both myself and the bike. The motor comes on strong off the bottom with lots of torque, but falls flat on top. Setup wise I could tell the balance and clickers were a bit off for my preferences, especially on a track that develops lots of chop and deep ruts. Still had a blast and can only imagine how much better I'll be able to ride once I more time to make adjustments.
After the Two Stroke Shootout I started with the first round of parts including a Boyesen ignition cover, Motoseat cover and foam, Cycra restyled plastics, Pro Taper grips, and carb vent hoses.
I also noticed a few scratches on the freshly powder coated frame so after researching the options for frame guards, Light Speed's carbon guards seemed like the way to go.
I also have a carbon skid plate on order from Light Speed for added protection and durability.
I'm excited to see the improvements once I get the bike back. My plans going forth are to fine tune the suspension, install graphics, and let 'er rip! Hopefully I'll be healed up in time to ride before winter
Upgraded the rear brake pedal to a Hammerhead Designs setup. I previously had a Hammerhead brake pedal tip when I had a KTM, and thought that it provided a better feeling than stock. Nice upgrade from a functionality and looks standpoint.
One issue I wanted to get fixed during this build was the front brake line setup. The previous install looked sloppy, and I noticed that the line was rubbing on the rotor and it was only a matter of time before a failure happened.
After
For whatever reason, the bike came with a 1997 YZ 125 front master cylinder installed, so we upgraded back to the 2003 OEM setup. The main reason being that it's much easier to adjust the front brake lever on the 03 and the fitment between the master cylinder and the throttle housing is improved.
Also time to get the top end changed, some porting, and hopefully Pro Circuit and the distributors pull through with getting the pipe in. Been on back-order for 6+ months.
Here's a sneak peek of the graphics. My brother designs custom graphics, so he hooked me up with a clean design.
More of his work can be seen on Instagram: @dabaum_designs
Some Vital members have probably seen his work on Zesiger 112's YZ 250. Zesiger 112 provided the design and he helped bring them to life.
The Shop
Graphics installed and scored an FMF 2.1 Ti silencer.
Turbo Speed Tuning rebuilt and revalved the suspension for my weight and fixed the clicker issue. Bike works so much better now. 🤘
While the suspension was off, I greased all the bearings and surprisingly they looked like they were recently packed. Also replaced all of the OEM bolts that I removed during the process with Specbolt pieces.
From here, finished the 2019 year off putting some time on it.
This past month, GBR Performance did a complete rebuild on the motor. Fresh piston, Hinson clutch, rebuilt crank, and replaced all the bolts with a Bolt Hardware engine kit. If you are around the Ohio area and need some work done I highly recommend Gary at GBR. Very clean and organized shop. Can tell he takes a lot of pride in his work.
Before & after of the head.
New pipe mount.
Ready to shred in 2020!
Upcoming plans are to replace the OEM rear caliper and brake disc guard with Light Speed Carbon and a fresh set of Dunlop MX33 tires. At some point, I'd like to get the brake calipers and master cylinders cerakoted and add an oversized rotor kit on the front.
Noleen was a big part of Yamaha's success in the 90s to early 00s when they switch to MB. Pipes were considered the best for the YZ. I'm still trying to find a 97/98 for my old 250 (which was ported by Noleen back in the day).
Bills pipes are just good pipes, I think he supported Suzuki a fair amount but they tend to wake up most brands.
PC was always a mid/top pipe but some felt they were a little flat on top compared to the Noleen and Bills.
Another option is a dynoport pipe who makes a mid top specifically.
Cool bike and can't wait to get my 02 done.
Plan on using him again this year for helmet wrap, updated graphics for yz, and maybe sticker sheet of small decals.
Pit Row
I sourced a good 98 top end, wheels, Bill's pipe, radiators, new plastic, and probably a couple hundred bucks of odds and ends to get it back together.
Took it for a warm up ride yesterday and man is it quick. My last race bike was a KTM 450 and the past few years I've been racing vintage big bores so I wasn't expecting much out of the 1/4 liter but it is quite zippy on the pipe! Not quite the show quality you guys have built but not bad for a low budget rescue!
Still waiting on a rear rotor/caliper carbon fiber cover from Light Speed. If anyone knows another carbon manufacture that makes them for a 2003 YZ125 please let me know! Been 6+ months since I ordered one and Light Speed always tells me they are still waiting to produce more of them. To be fair, they did say I wouldn't get charged until the part ships.
Other than that the entire bike has basically been gone through besides the rear brakes. Might tackle those as a winter project with some coatings.
Special shout to Bolt Motorcycle Hardware for getting me dished head bolts. I'm going to replace all of the remaining bolts on the bike to match the current dished head look on the engine (which is a Bolt kit) and front end.
Decided to stay away from any cerakote work because the theme is more blue, black, and silver. The only other mods I really have in mind are a set of Applied Triple Clamps so I can run 1 1/8 bars.
...Discovered fuel leaking out where the lower shroud bolt goes into the tank. Here's the culprit.
I have been planning on racing the Battle Creek Motorcycle Club Grand Prix this upcoming weekend (bigggg woods guy lol
Installation of the Clarke tank was straight forward but it did require trimming of the OEM rubber cushions to get the front gas tank mount properly aligned. If anyone reading this plans on buying a Clarke tank, be sure to clean it out with compressed air and rinse it out with gasoline. I found several large chunks such as this.
I am not totally stoked with the fitment of the Cycra shrouds to the tank. There is definitely a bit of gap between the shroud and tank but it will work for now. On my test ride I could not tell a difference in feel, but aesthetically it is enough to bug me. I'll have to find a solution over winter when I have more time. For now it will get the job done.
Looking forward to trying this thing out in the woods this weekend. I've strictly been a moto only guy. But events like the RedBud Grass Race have me itching to try a few different styles of riding.
I'll continue to post on here as the build and riding goes on. I enjoy looking back and seeing the progress.
Once it gets too cold to ride, I'll get over to GBR Performance for a fresh top end. I'm also eyeing a set of Applied Racing rubber mounted upper triple clamps. My bike currently has a "Universal Brand" top triple clamp and I just recently discovered the company previously had several recalls and some folks consider them cheaply made Chinese parts. It makes me a bit nervous to continue running them. I've been wanting to switch this bike to Pro Taper EVO 1 1/8" bars, so finding this just makes a good excuse to upgrade.
The bar mount height is basically the same as it was before. I installed a lower bar bend (Pro Taper EVO Husqvarna bend) as I had a few sitting around. I previously had the YZ High bend and always felt like the bars were too tall. This feeling was only exaggerated by the older two stroke ergonomics where it feels like sitting in a pocket on the seat.
Once I log some hours I'll update any thoughts, changes, or improvements with this setup.
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