1984 CR125R Restore Project

A friend of mine mentioned that he knew a guy that had a CR125R in his shed that had not seen the light of day in 25 years.  Seems the piston was bad and he took it apart and then life got in the way and there is sat all this time.  He had the motor stored in a cabinet and it was sealed so there were no issues.  I was able to get it for the right price of free and always wanted to restore a vintage bike that I rode in high school.  It's been 2 weeks and I've made some good progress.  Here it is on the way home, the rest of the parts area in the car and every nut and bolt was saved and marked.



Home in the garage ready for some work.


Sandblasting the frame to bare metal and soda blasting some aluminum parts.


The cylinder was sent out to be bored with a new piston.  I found that the magnesium waterpump side was toast and priced out the replacement unit from Australia (cast in aluminum) for $400 and decided to pass.  I prepped the metal with soda blasting and used JB Weld and it's about 1/4 - 1/2" thick in that area and far stronger than the original.  I'll run the Honda motorcycle antifreeze as I hear it's magnesium friendly.  New seals are on the way and will be installed.


I don't have a parts cleaner, so I had to plan that work when my wife was out with friends.  (Don't tell her).


Parts cleaned and awaiting install.  (the exhaust in the top right is not for this bike, it's an XR250R header pipe).


All decals are being replaced with reproduction units, including the rear fender warning decals.


Forks are rebuilt with new sliders, seals and wiper and will be dressed with new boots.


Frame received a coat of epoxy primer, followed with factory matched acrylic urethane, a far better finish that stock.


Slowly building the bike up from the ground.


New tires and tubes are being mounted on the rims.  I purchased an FMF silencer that had a spark arrestor so I don't get hassled if I do ride the bike.

Struggles of an old bike are rubber related since it does not stand the test of time, even in a shed that doesn't see UV light:

- Rear shock - struggling since the piston shaft had some rust and the part is no longer available.  Shipped to a rebuilder and he would not touch it after he saw the rust.    I'm researching a couple options on how to resolve this.   

- Intake boot - has cracks, so I put a film of black RTV on it so the assembly can move forward.  I found a reproduction unit for $110 and may purchase that.

- Chain sliders and roller - Ordered a set of roller and they were to big, but found a reproduction company and ordered both the slider and rollers there.

Very excited to get the wheels on so I can see it at the normal height.  The bike was free, but the receipts added up quick, but it's worth it so I have the bike that was around in the days I rode them.  Hoping to make some good progress this weekend after UPS drops parts almost every day this week.



Edited by dtmackey

Outstanding, I'll be following along with your progress as I just bought an 86 CR500. Mine isn't in bad shape at all with a partial previous rebuild to running condition. I plan to play with it for a while this summer then do a complete rebuild next winter. Good luck with your project. Where are you getting the parts and decals etc?

Cool project. My first full size bike was a 84 cr125, come to think of it my second big bike was also a 84. The first one was stolen while at the shop for a new top end. They replaced it with a fresh one right out of the crate.

Funny you should post a CR500, been looking for a good project one of those since they are monsters.  I haven't ridden a 2 stroke since 1986 and I'm more into the restoration process and having them to take an occasional rip around, especially since 2 strokes are no longer.  Came very close to buying a 1985 CR250 project the other day, but passed since it was too rough.

Most of the parts I'm finding on eBay and I'm being selective on things, some aftermarket, some OEM based on the part and importance.


Project finished.  Only the chain was left to install in this pic.


I've started it and it runs great.  Have not ridden it, aside of a blast around the neighborhood.  Bike will probably sit more than anything since it's more of a project and we have other bikes to ride.



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