1974 Yamaha MX125

[RE988]

So today while riding at the tack a few guys parked down the way from us were cruising around on some sweet vintage bikes. We got to talking and he says he's got a vintage bike in the shed he'll sell me for what he's got in it. Long story short I bought a 1974 Yamaha mx125 for $60.00. I know I need new plastics, cables, bars, air box, and the ignition side engine cover. Where should I start on this restoration project and where can I get parts besides eBay? Thanks!

[RE988]

The motor isn't locked up and has compression

[RE988]

I know the front fender is off of some kind of Suzuki and the only side plate on the bike isn't the right plate for it

[nucular]

You can get plastics and some other parts from dcvmx.com. eBay will be good for parts and the dealer will still be able to provide some - downs what you need.

[nyabinghi]

side cover and fender are wrong -  - airbox is attached to the rear inner fender - you will need one from either a 74/75 mx125 or mx175.  i believe ct3/at2/at2 ignition cover will fit.  other wise you need 74/75 mx125/mx175 ignition cover.- i have a spare airbox, but it's been detached from the inner fender so it's kind useless without the fender..  i believe kicker is wrong too - can't tell from pics - if you use wrong kicker it can crack the clutch cover at the bottom of the stroke (look for a ding where pinch bolt would hit bottom of clutch cover when kicker is all the way down..)

Edited May 19, 2014 by nyabinghi

[Qqqqqqqqqqqq]

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I know the front fender is off of some kind of Suzuki and the only side plate on the bike isn't the right plate for it

The side panel is off the 76' 77' RM Suzuki .

[RE988]

The side panel is off the 76' 77' RM Suzuki .

is that what the front fender is for too? The guy gave me a box with a bunch of random parts from like 4 bikes in it. I found the intake manifold, air boot, full plastic kit, and the flywheel/stator cover on eBay already Edited May 19, 2014 by RE988

[Qqqqqqqqqqqq]

Could be .. I had a New RM back in 77' .. I can't be 100% sure on the Fender

[RE988]

Could be .. I had a New RM back in 77' .. I can't be 100% sure on the Fender

Awesome. Thank you!

[RE988]

Has anyone ordered new parts from the dealer for a vintage bike? I found a parts diagram on my local Yamaha dealer website and can order parts. My bike I ride now is 4 years old and dealer parts take around a week to get in. What's the wait on parts for a bike that's 40 years old?

[nucular]

Has anyone ordered new parts from the dealer for a vintage bike? I found a parts diagram on my local Yamaha dealer website and can order parts. My bike I ride now is 4 years old and dealer parts take around a week to get in. What's the wait on parts for a bike that's 40 years old?

I have bought many things from the dealer for my 79 YZ400. The wait has been no different than the wait for my newer bikes.

[knudsen]

Me too, and no difference in the wait for on-line suppliers, except additional shipping time and expense. Almost all my OEM parts come from my local third part dealer.

[RE988]

Awesome! Thanks for all the help guys. I found all the parts I was missing on eBay. Once I rebuild the motor and suspension I'll order all that new from the dealer

[rob the snail]

i had one i bought new back in the day...first mx bike i payed cash too..$495 traded back to the dealer 6 months later for $425 when the yz125c came out...i made mine go faster by changing the pipe to a stinger type and think i ported it as well....good reliable bike and from personal experience when you race vmx its often better to have a reliable bike than a faster one...enjoy...ohh and i moved the shockies up for more travel too..forks were average tho

[SFDemo]

I've built many vintage bikes (mostly Yamaha) and the guys at Speed and Sport in PA are great.  I would not bother ordering parts from a local dealer, got to specialty vintage people, you will be way happier. I was a parts guy at a Yamaha and Kawi place in the 80's and getting parts through them then was a bitch, once I started vintage racing, found most of my parts online.

 

Buy a manual, most of the work is relatively simple other than crank rebuilding and can be done in your home shop.  Most cases come apart easy and all the seals and gaskets are available as a kit.  Have a reputable mechanic check your crank pin bearing and main bearings.  The other stuff usually doesn't wear badly unless the bike is thrashed.  A lot depends on where you are.  There are vintage engine builders all over.  Replace the steering head bearings with tapered rollers, put in a fork kit and seals and buy good shocks after painting the frame.  I have always used either Fox Shocks (old style with springs) or Works Performance.  There are options for airbox issues, eBay obviously.  Mid Ohio is another if you are around there, and stuff can be found reasonable.  The hot ticket is to use YZ forks and wheels if you can find them, preferably off a 250 (bigger diameter). A lot of later YZ wheels will fit and look cool with the gold anodized rims, plus usually have better brakes.

DC plastics makes nice kits and Clarke Manufacturing makes tanks.  I bought a used plastic yellow YZ style and used plastic renew to make it look good on my MX 250.Cirlce F makes a pipe that rips when combined with a Penton Racing Products PVL ignition.  

 

Good Luck

[knudsen]

I 2nd on the larger forks. On my old SP, I went from stock 35 mm to 38 mm RM forks, and in addition to more travel and a better ride, I instantly noticed more stability on street. Innerds are the same design, RM yokes further apart, but I imagine the biggest improvement is the wall thickness of outer and the chromes, which I forgot to measure.

Just be careful of the vintage rules before changing stuff if you plan to race it.

[RE988]

Wow there's a lot of good advise here! Thanks a lot! I'm is south Texas (San Antonio) and not sure if there are any vintage shops around these parts. I do have a buddy that runs a shop that did a lot of great work on my race bike. Another question for y'all, I got a oil injection delete kit. It's just a plate and gasket that blocks off the port where the oil pump goes, but there's a spot on the carb where the oil line would go in. Do I have to cap that off with something?

[knudsen]

Yes or it sucks air. Get a vacuum cap assortment at autoparts in the help section,, or the ugly bit of hose, bolt in the end and hose clamp until you get a cap that fits.

[nyabinghi]

. Another question for y'all, I got a oil injection delete kit. It's just a plate and gasket that blocks off the port where the oil pump goes, but there's a spot on the carb where the oil line would go in. Do I have to cap that off with something?

oil line goes in right side of cylinder in front of reed cage.  you need a bolt and fiber washer to block that off.  the carb has no oil injection.  that's either a vent or overflow line.

 

do not cap off any lines to your carb.