Brakes adjustments

[El__burro]

Good day, i have almost finished my project (just left to change the rear tyre and complete registration of my cb750 k2).

After having filled up my front brake system with oil i have a problem.
The front wheel is pretty hard to turn as the brakes pads are holding on the disks.
I have a dual front brake.
The disks seem pretty straight.

Any ideas for sorting this out.

Thanks a lot
El__burro

[Johnwebley]

when I fitted dual discs I had that issue on the OS/new side,
the caliper alignment is crucial,as it needs to press the pads directly onto the disc,

I was lucky,I could ride the bike,then check the rubbing part of the pad,and make adjustments with a file,

try removing the pads,then see how well the caliper meets up with the disc,
you might find either the top,or bottom touch first,

does the lever feel soft/spongy ??

make sure the moving pad slides in the caliper easily,

[El__burro]

it looks like the moving pad on one side ( the other is fine) that doesn't retract.
I guess i need to remove the calliper and inspect it to work out why is not sliding in.
the lever feels soft, no friction or pressure.

thanks
el__burro

[NigelWilmshurst]

I had the same problem on my twin disc conversion, after lots of headache I realised the piston seals I had ordered from David silver were too big and not allowing the pistons to return freely, which also created drag on full lock, ordered the correct seals through my local honda dealer and filed the pads.

Eventually sorted the problem out, the lever feels slightly spongy but actually works fine, the F2 reservoir may of been a better choice as it's bigger.

Nigel

[El__burro]

i thought of removing the calliper to have a look but then i realised that the disk is probably not straight as when i spin the wheel it goes free one a side and stuck for another bit.
if that is my problem, how easy is to fix.

Thanks
El__burro

[Johnwebley]

check the disc mounting

   "             " for warping,(the same way you would true a wheel rim,

 if its distorted,I guess its scrap,

[El__burro]

In the pictures below it's visible the variance on the disc.
Not sure if this means that the disc is not good or there is a tolerance "allowed"

Thanks
El__burro

[Bryanj]

Is the disc carrier fitted squarely on the hub?

[El__burro]

I guess the only way to tell is by removing the disc and put it on a flat surface. I'll check for the bolts tightness first. Do you know what's the torque setting?

Any other suggestions?

Thanks
El__burro

[Bryanj]

before trying to tighten I would make sure there is nothing contaminating the mating surfaces, You haven't tried to use a standard speedo drive plate have you?

[El__burro]

After tightening all the bolts to 40 nM the disc seems straight.
The wheel spins free but when I pull the brake it goes a bit tough until I punch the calliper towards the wheel.
I guess the punch helps the pad to retract once it hits the disc.

Thanks
El__burro

[Johnwebley]

it seems the pad is meeting the disc squarely,


 roughen the pad surface,re-fit and spin the wheel,then un assemble,see were the disc is rubbing the pad,use a file to take away the
high spot,continue until the wheel spins,and make sure the piston retracts,and the pad moves easily on the caliper.

the fixed pad is almost self aligning,

[El__burro]

After removing the calliper and unsticking the brake pads (it had some extra bit on one side) the disk turns freely;
the new issue is that i need to pull the brake lever a few times before it locks the brake.

what shall I do next?
thanks
El__burro

[hairygit]

Try adjusting it. Undo the locknut and adjust until there is just about 6thou between the fixed pad and the disc.

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