1984 Cr250 - Scr Pair

I have been looking for 1984 CR250 to restore and found this pair. The reason for this year and model is because I rode and raced the same bike in the mid 80’s until I traded it to a KTM. This pair of bikes is only 7 digits a part on their frame and motor numbers and as far as I can tell, they were put together by SCR of PA to be water cooled WRs. They both have WR flywheels and moto plates. The rear fender loop on one of them is welded and made from bent pipe with a tool bag holder. The other bike appears to have a loop kit that has small bolts through the frame holding it in place. Both have been setting since around 2012 and was parked semi environmentally controlled basement with no storage prep.

This pair is unique to me because if you think about it, they have been together since they left Sweden. I have reached out to a guy in PA on FB who might know someone who has more knowledge to why they built and who they were for. Please let me know if you know any of their history. To me the history of their journey is also great part of the restoration.
The investigation and teardown begin.

I have decided to start with this bike. It is not turning over; I suspect the crank. The forks are pitted and the fenders are crap. The pipe is straight and the motor looks to be freshly painted before it was put away.

First, I wanted to see what Flywheel was on the bike and what was the status of the water pump housing. The flywheel was what I suspected. The CR flywheel would not support any lights.


Water pump housing - The antifreeze was nice a green and at first glance I thought the cover may have been aluminum. No suck luck. After putting a little light on the situation it was clear someone had already repaired it and the antifreeze got under the epoxy. The other picture is what it looked like after I picked off the epoxy. While not pretty it looks like it can be repaired again.

I also drained the oil and it had no water and was not burnt.

Gave it a good wash before disassembly.

Pulled the cylinder off. Discovered the piston is 69.4 after cleaning it off. The rings were not stuck.


The head looks go and will clean up well.



The cylinder appears to have been re-sleeved and some port work done similar to what is referenced in the tech bulletin. I measured the bore using the piston and some feeler gauges and the bore is still in spec. I will be putting a dual ring piston back into it.



The crank was definitely stuck. I put some muscle on the flywheel and broke it loose. It had some corrosion between the crank and the case. I'll get a better look when I split the cases.

Had the same problem with my 430
Soaked it with Kroil for a week got it unstuck cleaned it up new gaskets freshened up the carb runs good as new

Very interesting bikes you've found. A pair is always fun. I bought a pair once and it was so much fun.

I've had pretty good luck with "previously running" bikes if I take the motor apart, clean everything, and reassemble. Hopefully you can split those cases and be back on the trail. And if you are going that far into the motor, put new crank seals in. They will be dry and brittle, and might last for a ride or two... and then fail. Do it now. Once and done, right?

I removed the motor out of the frame and split the cases. The motoplate backing plate was corroded but will clean up. The internals all looked good, and it has a completely new clutch including hub and basket. I cleaned up the corrosion in the crank area with a wire wheel and will repair the pitting with the Devcon when I do the water pump housing.

I am sending the crank off to be completely rebuilt to Mr Crank in KY. I’ve ordered all bearing seals, gaskets, and piston kit.

The flat carb is toast so I’ve ordered a Mikuni 38mm round slide and a few jets that should work. The air intake boot was also gone so I’ve got one of those on the way too. Before I forget, I need to order some reeds too.

A few updates:

- Cut off the added frame loop
- The frame and bits are off being painted
- I stripped the shocks of their paint, and they are being service and valved for my weight and the springs I plan to use
- Stripped the cylinder and triple clamps of paint and deciding if I want to spay them black are us an aluminum color on cylinder and head and polish the triple clamps. I worked a lot of imperfections out of the clamps. However, they still have some pits from being cast.
- Cleaned up the intake and the exhaust on the cylinder
- Fixed the water pump and cases where needed with Devcon.
- Sanded prep cases for painting
- Front wheel is tuned and spokes polished.
- The rear wheel’s spokes had more than a few band nipples and I am in the process of painting the hub and re-spoking the wheel
- Rebuilt the crank with new pin, bearing and rod
- Stripped the pipe and fixed a few flaws. It is off getting a black ceramic coating.
- Fork tubes shipped off to have new hard chrome. I purchased three pairs that all had flaws in the stroke area and just gave up.

I believe I have everything I need to start the assembly once I get all the major parts back from painting and service. I will try to document the reassembly better. On ward and Up ward!

Here are a few pics of the progress:

Shocks


Water pump Fix


Cylinder, Head and Triple Clamps, Note the mold line has been removed on the bottom triple. I am thinking about polishing triples and having them clear powder coated.


The exhaust port cleaned up. It was ugly.

Keep up the good work! Keep us posted on the progress.
Am doing a total restoration to my 83 430
No engine work, just frame and plastics, triples and shocks and forks.