250-500cc Rear Brake problem 2001 CR250 Husky

I recently bought a low hour 2001 CR250 Husky.Just a little history about the bike. I am the 2nd owner. This bike was sitting in a shed for 12 years not being rode. I made an offer and my friend accepted. So I brought the bike home and checked every thing out on it and put some new parts on it like handle bars,Bark busters, oring chain, Renthal rear sprocket and tires because the stk tires where dry rotted. So once I got it all set up I took it for a ride and after about 15mins of riding I went into a turn and hit the back brake and it was like it wasn't there, no REAR BRAKE. So I thought that I may have missed it with my foot so i didn't think nothing of it. Then about 10mins later and riding it, I went to use the back brake and it did it again. I was going into a turn and hit the back brake and nothing. So my question to anyone that could help me out with this issue is what can be the cause. This is what I didn't do so far. I didn't change the brake fluid in the back brake or in the front. Not sure if that is the issue. If anyone ever experienced this please share what the fix is.. I do plan on changing the fluid because it is 14yrs old. The pic is the condition of the bike how I brought it home and one of how it looks now.

That is immaculate. Who buys a new bike and sticks it in the shed virtually new to sit for a decade and a half!

Replace the fluid front and rear with a good bleed and see how you go.

that is sick clean
by the way the blue fender does not really fit
so back to the brakes, are you inferring they work sometimes or not at all??

Yes the rear brake will be working then when you are hammering and go to use it no rear brake. But yes they work and it doesn't.

I'd say you have very contaminated brake fluid, with a lot of moisture in it. It most likely is the original fluid, that was never changed. Brake works cold and then as you heat them up, they go away. Go buy some DOT 4 fluid and flush and bleed the rear brake.

That is one fine looking CR250 you found. Sounds like brake fade so new fluid should fix you up. Disassembling the brake caliper and lubricating everything should help too.

You are gonna love that bike! I keep goin for the cr when I ride !

Well this is my plan I ordered Motul Brake Fluid DOT 5.1 and I also ordered a new master cylinder so i should have them by this Friday and will change the master cylinder/pump and the fluid in both the front brake and the rear brake. I will also lubricate brake calipers front and rear. I will let you guys know how it turns out..
Thank you for your advice... CoS

I cant believe how clean that bike is-score!

Bled the front and rear brake and put Motul RBF 600 Racing Brake Fluid DOT 4 in it, It says that 600 Racing far exceeds the standards for DOT 4 and the extremely high dry boiling point of 594° and wet boiling point of 421° provides fade free operation. I hope that this solves the problem. The original brake fluid that was in there did not have a good color to it at all. Can't wait to try it out Saturday.... I will post ya's on how it works.. Thank you: CoS

My friend and I bleeding the frt brake on the HuskY....the rear is done already...

Wow, that thing is pristine. Really brings the memories. Sell it to me.

Don't ride it keep it safely tucked up for another decade and punt it out unridden...
Let the future buyer sort brake fade out, bottom end still good? Conrods dont like to be sat that kills 2smokers.
I liked blue fender the side panels rolled nicely into it.
Good score.

Is there something you could (or should) do to help with the conrod if you are restoring on old bike?

Replace it.
or run it bi monthly, the fuel is corrosive as moisture is drawn in through natural humidity in the air, that gentelly eats at the hardening had one on my 360 wich had been sat for a year from previous owner. i was told by the bloke that replaced my rod that was from being sat still too long as it would of worn more evenly over the rest of the big end.

I could be wrong but i run my bike as much as possible to prolong the life of the motor thats what i tell the missus.

P.s. CoS I love the fact your truck makes the husky look like a dinkey toy!

welcome to america! where our bikes fit with the tailgate closed! altho long beds are a trend that has faded, as less people use their truck for work

Youve seen our pitiful pickup trucks then pmsl
I bought a van just so i can get the bike in with the doors shut!
Our roads are too small for big cars plus school runners in 4x4's block the street trying to get past eachother.
Nightmare i need to emigrate

It really depends on what type of fuel and mix oil was in it the last time it ran. Some race fuels are stable for up to 30 years, plain old VP110 is good for 3 years. Some mix oils contain corrosion inhibitors (most outboard/marine mix oils) which can add time to that. However if the last fuel that was in it contained ethanol, you're pretty much screwed.

Most casual riders dont use race fuel, i dont i use premuim from shell with putoline mx5 so i run the gal ragged an often.
30years stable what fuels that i will buy a tank an run it throug bike before i leave it for a while.