2003 Yamaha YZ125

MotoRoss678
Posts
178
Joined
2/16/2016
Location
Waynesburg, PA US
9/18/2017 10:17am Edited Date/Time 4/9/2018 12:45pm
Just picked up this 2003 Yamaha YZ125 a few months ago...let the building begin.

All questions and comments are welcome...

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mattyhamz2
Posts
10850
Joined
7/6/2015
Location
So Cal, CA US
Fantasy
760th
9/18/2017 2:44pm
I miss my 03 every day. Cant wait to see how this build goes!
MotoRoss678
Posts
178
Joined
2/16/2016
Location
Waynesburg, PA US
9/18/2017 4:49pm Edited Date/Time 9/18/2017 4:57pm






Just a little more progress this afternoon. Did the primer and flat black bedliner paint before hitting the gym for a few hours. Upon inspection, I'm pretty happy with the way the flat black is turning out as it dries. I think I'm going to add another coat later on this week and give it a good 2 days to fully dry.

Still debating on whether or not to take the wire wheels to the swing arm and black it out as well.

I'm really trying to take all the time in the world and make this build unique. Stay tuned...

The Shop

MotoRoss678
Posts
178
Joined
2/16/2016
Location
Waynesburg, PA US
9/18/2017 4:56pm
mattyhamz2 wrote:
I miss my 03 every day. Cant wait to see how this build goes!
I appreciate the enthusiasm buddy! Any advise in the motor department for this model?

In a past build (2004 Honda CR125) I had great success with a Wrench Rabbit kit, consisting of a HotRods crank and wiseco topend.

This craigslist find has an Athena cylinder on it. I haven't cracked the motor open yet to see what horrors (or joys) await me, but I'm pretty certain that I will be bitting the bullet on an OEM cylinder and topend just for peace of mind.

I plan on replacing the bottom end with a hotrod crank and possibly ceramic bearings.

As for the body work...I think I'll leave that mystery alone until further on down the build. Let me know your thoughts.
9/18/2017 5:01pm
I would vote no for swingarm coating.. I had my old RM swingarm powder coated black and I spilled brake fluid when I was bleeding the rear brake and it screwed the powder coating up.. I don't know if something like that could happen to the bed liner though
9/20/2017 5:44am Edited Date/Time 9/20/2017 5:44am
I appreciate the enthusiasm buddy! Any advise in the motor department for this model? In a past build (2004 Honda CR125) I had great success with...
I appreciate the enthusiasm buddy! Any advise in the motor department for this model?

In a past build (2004 Honda CR125) I had great success with a Wrench Rabbit kit, consisting of a HotRods crank and wiseco topend.

This craigslist find has an Athena cylinder on it. I haven't cracked the motor open yet to see what horrors (or joys) await me, but I'm pretty certain that I will be bitting the bullet on an OEM cylinder and topend just for peace of mind.

I plan on replacing the bottom end with a hotrod crank and possibly ceramic bearings.

As for the body work...I think I'll leave that mystery alone until further on down the build. Let me know your thoughts.
"Hot rods crankshaft, and ceramic bearings"

I wouldn't waste your money if you're putting a hot rods crank in it, then again it is your money
9/20/2017 5:56am
I appreciate the enthusiasm buddy! Any advise in the motor department for this model? In a past build (2004 Honda CR125) I had great success with...
I appreciate the enthusiasm buddy! Any advise in the motor department for this model?

In a past build (2004 Honda CR125) I had great success with a Wrench Rabbit kit, consisting of a HotRods crank and wiseco topend.

This craigslist find has an Athena cylinder on it. I haven't cracked the motor open yet to see what horrors (or joys) await me, but I'm pretty certain that I will be bitting the bullet on an OEM cylinder and topend just for peace of mind.

I plan on replacing the bottom end with a hotrod crank and possibly ceramic bearings.

As for the body work...I think I'll leave that mystery alone until further on down the build. Let me know your thoughts.
"Hot rods crankshaft, and ceramic bearings"

I wouldn't waste your money if you're putting a hot rods crank in it, then again it is your money
What's wrong with HotRods?? I've used a hotrods crank on 2 rebuilds and they both worked well.. Not being a dick I honestly wanna know about your experience with them..
9/20/2017 9:44am Edited Date/Time 9/20/2017 10:08am
What's wrong with HotRods?? I've used a hotrods crank on 2 rebuilds and they both worked well.. Not being a dick I honestly wanna know about...
What's wrong with HotRods?? I've used a hotrods crank on 2 rebuilds and they both worked well.. Not being a dick I honestly wanna know about your experience with them..
I'm not trying to be a dick either. With the price of OEM stuff out there now I wouldn't bother with aftermarket. I'm not putting the company down. I just wouldn't chance "that" crank in a 125. My friends have had problems, they are cheap for a reason. I would get the crank rebuilt with a new rod and bearings
nicko-31
Posts
411
Joined
12/8/2014
Location
NY US
9/20/2017 12:16pm
What's wrong with HotRods?? I've used a hotrods crank on 2 rebuilds and they both worked well.. Not being a dick I honestly wanna know about...
What's wrong with HotRods?? I've used a hotrods crank on 2 rebuilds and they both worked well.. Not being a dick I honestly wanna know about your experience with them..
I'm not trying to be a dick either. With the price of OEM stuff out there now I wouldn't bother with aftermarket. I'm not putting the...
I'm not trying to be a dick either. With the price of OEM stuff out there now I wouldn't bother with aftermarket. I'm not putting the company down. I just wouldn't chance "that" crank in a 125. My friends have had problems, they are cheap for a reason. I would get the crank rebuilt with a new rod and bearings
True that .
smezmx
Posts
2618
Joined
5/25/2010
Location
Kent,medway.... GB
9/21/2017 5:19am
[img]https://p.vitalmx.com/photos/forums/2017/09/18/215429/s1200_IMG_0503.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2017/09/18/215430/s1200_IMG_0504.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2017/09/18/215431/s1200_IMG_0505.jpg[/img] Just a little more progress this afternoon. Did the primer and flat black bedliner paint before hitting the gym for a few hours...






Just a little more progress this afternoon. Did the primer and flat black bedliner paint before hitting the gym for a few hours. Upon inspection, I'm pretty happy with the way the flat black is turning out as it dries. I think I'm going to add another coat later on this week and give it a good 2 days to fully dry.

Still debating on whether or not to take the wire wheels to the swing arm and black it out as well.

I'm really trying to take all the time in the world and make this build unique. Stay tuned...
If you do the swinger pro carbon racing in the UK sell a swingarm protector which looks great and offers side impact/paint protection.i have one on my 03 250.just put any graphics/decals you have on the guard's.polisport also sell plastic swingarm protector's in different colours but i don't think for your model bike?

https://www.pro-carbonracing.co.uk/yamaha






MotoRoss678
Posts
178
Joined
2/16/2016
Location
Waynesburg, PA US
10/1/2017 8:38am
Just a few updated photos...Most everything has been sprayed. I'm doubting that the black bedliner spray will last. I'm not seeing that it has bonded very well with the aluminum components. I expect to be tearing this bike back down after a few rides to sand blast everything and have it cerakoted.

I can't say that I was surprised at the condition of the motor. The head shows some detonation so it went in the trash. (Along with a cylinder from my 2004 CR125 that was laying around...guess it was time to start cleaning out the shop)

I haven't made a decision on the cylinder yet. The top of the sleeve shows pitting and detonation so it will most likely be getting replaced or sent to millennium technologies.

It looks like I am going to put a Buds Racing head on this once I get to that point, but we will see.

I'm still messing with the idea of tearing down the suspension myself to beat that learning curve. Stay tuned...

Let me know what you guys think!
MotoRoss678
Posts
178
Joined
2/16/2016
Location
Waynesburg, PA US
2/8/2018 9:51am
Sorry for the delay guys! Holidays, wedding preparations, new job, energy sector picking up big time, and the list goes on! I have some updates for yall and I am really looking forward to hearing your reactions!

First is the latest photo of the bike with the front wheel all laced up and NOT TRUE by any means! Anyone feel my pain?!?! I've never been good a truing wheels, but I think I'm gonna make it a point to practice and become proficient at it!

There's a few pics as well in here from the case splitting process. The Yam is a good bit different from the old CR125's I had been used to working on, but I'm always game for a challenge and adding new skills to the folds in the grey matter. There's also two different color schemes I was looking at for my Fasthouse MC inspired graphics.

"Cool side story...I wasn't quite sure what theme I wanted to pursue with this build until I was having breakfast in the Hard Rock Las Vegas before heading over to the Monster Cup this past October. I was having a blast there with my bachelor party! If your getting hitched, I highly recommend a few days in Vegas (just a few, too many could be bad...like really bad). Anyhow, while we were waiting to be seated, a gentlemen walked up to me and said "Thanks for the support (referencing my Mixin' Gas & Haulin' Ass tee), just wait till you see what is coming out next!!!" Turns out he was one of the FHMC partners! That right there made the trip! It also concreted my idea for putting the Mixin' Gas logo on my newest project!" RK

You will also notice that I went with a black Clarke MFG tank. I just couldn't resist!!! I have my eye on a lectron fuel systems carb, but I want to get this thing running and mostly complete before I go that far. This will be a totally new ride for the most part. Who knows?!?! I might love it or turn right around and sell it to build something different.

Enjoy and let me know what ya think!!!!















luis97
Posts
202
Joined
5/20/2016
Location
Ridgewood, NY US
2/8/2018 10:06am
This build is amazing
mattyhamz2
Posts
10850
Joined
7/6/2015
Location
So Cal, CA US
Fantasy
760th
2/8/2018 1:11pm
mattyhamz2 wrote:
I miss my 03 every day. Cant wait to see how this build goes!
I appreciate the enthusiasm buddy! Any advise in the motor department for this model? In a past build (2004 Honda CR125) I had great success with...
I appreciate the enthusiasm buddy! Any advise in the motor department for this model?

In a past build (2004 Honda CR125) I had great success with a Wrench Rabbit kit, consisting of a HotRods crank and wiseco topend.

This craigslist find has an Athena cylinder on it. I haven't cracked the motor open yet to see what horrors (or joys) await me, but I'm pretty certain that I will be bitting the bullet on an OEM cylinder and topend just for peace of mind.

I plan on replacing the bottom end with a hotrod crank and possibly ceramic bearings.

As for the body work...I think I'll leave that mystery alone until further on down the build. Let me know your thoughts.
Honestly, I rebuilt mine with a new stock cylinder and piston. I went oem on everything. Next one I do though will probably have some porting done. Nothing to major though. I wish I would have kept it and put some time into fine tuning the carb and doing plastic, graphics, wheels etc.

Your bike looks amazing so far though. Im diggin' the black and yellow look, especially the yellow hubs. Cant wait to see her finished!
MotoRoss678
Posts
178
Joined
2/16/2016
Location
Waynesburg, PA US
4/9/2018 12:45pm
Alright guys here is the latest!!!

So at the end of Feb. my best friend and long lost riding buddy moved to the Permian Basin here to take his shot at the latest boom in crude oil production. In doing so, he placed himself back in the crosshairs of the motolife. I made short work of settin' him up to get back out on the track for the first time since 2007 on my 2012 Honda CRF250R. Long story short, he's hooked again and looking to get on board a 2018 450 at somepoint. (Seriously trying to talk him into picking up a craigslist basket case and designing a build).

That being said, I loaded up the YZ and decided to move up the maiden voyage despite knowing better to join him in some long awaited track time! Half a lap around the track something went horribly wrong and the clutch side case was toast. Turns out the main drive gear bolt that goes into the crank had come loose. I believe that I probably forgot to tighten it during reassembly. Hey! I'm human and made a mistake, but after waiting a few days on parts while on a business trip to Mexico, I pulled her apart and set to correcting the little mess I had made for myself. That brings us to the rest of this post. I'll spare y'all the rest of my ramblings and set ya up with the final finished product!!! Enjoy!!! Follow me on instagram @jetsettinsavage for future builds, track pics, and videos of the adventures based out of West Texas! Thanks for following!!! Please share your thoughts positive and negative!!!















































PJRAUS
Posts
1532
Joined
5/28/2016
Location
AU
4/14/2018 1:39am
Great build! Looks awesome!

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