1987 CR 125R restoration

anderson750

I'm working on it Rose
Location
Price, Utah
Last year I picked up this 1987 CR 125R mainly for nostalgic reasons. '87 was the year I qualified and competed at Lorettta's on a CR 125. With my son running last year, I did not get any time to start on the restoration and after everything for the season finished up, I left the bike on the back burner. Well, I finally decided to get going on this project so I took an evening and tore everything down.

Overall the bike is pretty clean for being 32 years old. I picked it up out of Washington from a guy who acquired it form along with an 87 CR 250 that he bought to restore. He claims that it ran when he picked it up, but I never did try and start it. Pushing the kick starter, it has good compression and everything feels smooth.



Let the tear down begin.



Onto the motor. I didn't anticipate any major surprises, but also did not expect to see everything in perfect order. The first thing I discovered was that it did not have any coolant in it. With that, I thought maybe I would find it all in the transmission since it was not unusual for these bikes to have a bad water pump seal. Surprise #2 was the lack of much oil in the transmission....and no coolant in there.

Well, lets tear into it and see what we find.

The top of the piston had no carbon build up on it, so I am assuming the piston in it does not have many hours on it. However, at some point in its life, something has come apart. I did measure the ring gap and it is only .011.

I think it is possible to believe that it has had coolant get int the crankcase. You can't really see it in this picture, but there almost looks like "lime pitting" in the aluminum. Along with that, based on the coloring on the cylinder wall and the crank, It has had moisture moisture in there, even though there was no fluid in the crank case.



Other than the discoloration on the cylinder wall, the cylinder looks great. no scarring or abnormal wear and the cross hatching is very visible. I pulled the ignition and found this crank seal sitting a little bit funny.

Onto the right side of the case, there is definitely some gunk in the water pump channels. I will most likely have Mylars clean the radiators.

Something a little funning going on with the clutch plates here.



Other than that, everything on the clutch side looked good. When I split the cases, the transmission looks great and other than the color of the crank, it looked good. It is almost like an oily rust. I will see how it looks when I clean it up. I measured the gap between the crank and thrust washers and it was only .019. I will have to look and see what it is supposed to be new, but I don't believe this crank has many hour on it.



Parts, parts, parts

 

anderson750

I'm working on it Rose
Location
Price, Utah
This afternoon I media blasted the frame at a friends shop and dropped it off to another friend to get painted. I was going to powder coat it but decided the extra expense was not necessary.


Next up will be to get the cases and a bunch of other parts vapor honed. Does anybody have any recommendations for somebody to vapor hone?
 

Tonkaman

Well-Known Member
Location
Taylorsville
This afternoon I media blasted the frame at a friends shop and dropped it off to another friend to get painted. I was going to powder coat it but decided the extra expense was not necessary.


Next up will be to get the cases and a bunch of other parts vapor honed. Does anybody have any recommendations for somebody to vapor hone?
I think we should all pressure Stratton into buying one...
 

Rot Box

Rot Box Toy
Awesome! Looking forward to this one :cool:

82-88 Honda’s have magnesium water pump housings that are famous for rotting (electrolysis) out and leaking coolant into the transmission. There are options with the cr500’s and certain 250’s for housings made from aluminum that fit these years but to my knowledge there is nothing out there for the 125’s. If you do hone that case be super careful in that area.
 
Top