Rear tire jams after a couple of laps!!

khan

khan

RideTheKKH.com
Hope everyone’s well on here!

I’ve run into a problem with my 2002 YZ250F

I ride it 2-3 times a week on the motocross track, everything was great till last Sunday the rear tire just jammed. I put it in neutral and tried to push the bike but it was impossible. I put the bike up on the stand and the rear tire was completely stuck. After cooling the bike down for about 20 mins the rear tire had movement once again.

I took off the master cylinder and the calliper, cleaned everything up and then I put fresh dot 4 oil and it seemed like it’s fixed.

Took it to the track and after barely 3 laps the tire got stuck again and saw some smoke out of the rear calliper.

Not sure what to check or replace now.

Any help would be appreciated.

Thanks BARF!!

Khan
 
Maddevill

Maddevill

KNGKAW
Sounds like the rear caliper is not releasing. Can be caused by over filling the reservoir or the bleed port in the master being blocked thus not allowing the pads to retract. A thorough cleaning and inspection is called for.

Mad
 
295566

295566

Numbers McGee
Maddevill said:
Sounds like the rear caliper is not releasing. Can be caused by over filling the reservoir or the bleed port in the master being blocked thus not allowing the pads to retract. A thorough cleaning and inspection is called for.

Mad
Click to expand...

x2

Also check to see if there's a spring between the master cylinder and rear brake pedal, that's supposed to help return the pedal to the unpressured (off) position after applying brake. If the spring is missing or worn out, it might not be relieving pressure.

Alternatively, but less likely, the rear master cylinder and/or caliper may need rebuilding.
 
augustiron

augustiron

2fast 2live 2young 2die
Make sure there is at least a hair of free play before the lever starts contacting the MC piston. This is an easy external adjustment to give free play.
I had a customer's duc monster do this, cooked the rear rotor and locked up at speed because he adjusted the free play out when moving the lever height.
Heat building up from a bit of pressure starts to increase pressure until you are fubar.
Quick fix is to crack open the bleeder to release pressure to get you home, and don't touch the brake again until it's fixed.
 
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Jalopyshoppe

Jalopyshoppe

idiot
Check that your brake pedal is returning all the way. If it's not letting the M/C fully release, the crossover (bleedback) port will not open fully and pressure will accumulate.
 
anytwowilldo

anytwowilldo

Well-known member
augustiron said:
Make sure there is at least a hair of free play before the lever starts contacting the MC piston. This is an easy external adjustment to give free play.
I had a customer's duc monster do this, cooked the rear rotor and locked up at speed because he adjusted the free play out when moving the lever height.
Heat building up from a bit of pressure starts to increase pressure until you are fubar.
Quick fix is to crack open the bleeder to release pressure to get you home, and don't touch the brake again until it's fixed.
Click to expand...

+1
 
KooLaid

KooLaid

Hippocritapotamus
Possibly sounds like you might of accidentally swapped the left and right side axle spacers, which is causing the rotor to rub against the pads and overheat.

Or you've got a stuck caliper piston

Or your back wheel is out of alignment and causing the rotor to rub on the pads.
 
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