Rear brake rebuild?

[Yoyo]

For the past 2years I have been rebuilding my GT650r from the ground up.

The project is coming to a close now, but one problem persists.
If I push the rear brake the lever stays down until I lift it again. And locks the back wheel.

Not sure if it needs a full rebuild or just cleaning up. Any ideas, what it could be?
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Joe: I don't wish to floccinaucinihilipilificate your choices, but the best word in the world is gaylord.

[P.addy]

[Kickstart]

Hi

First thing to check is that the pivot for the brake lever is free. Build up of corrosion there could cause a problem like this. Strip it and clean / lube it.

Failing that I would say the most likely cause is the master cylinder. Possibly the return spring in there has corroded away / broken.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Yoyo]

I powder coated the rear sets last year, and made sure that they were properly cleaned up before doing the rebuild on them.

I thought it might be a bleeding problem so did that, and it worked for a bit then went back to being stuck again.

How would I go about finding if the spring is snapped?
____________________
Joe: I don't wish to floccinaucinihilipilificate your choices, but the best word in the world is gaylord.

[Kickstart]

Hi

How does the lever pivot? On a bolt? Is there a bush between the bolt and the lever? Would expect that the powder coating wouldn't have been on a surface on which it was pivoting.

Beyond that you would need to strip the master cylinder. Never seen a diagram of a Hyosung master cylinder, but normally you will have a rubber outer boot and under that you will find a circlip. Remove the circlip and the piston should come out.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Yoyo]

The lever is on a peg cast with the rear sets and held in place with a circlip. I didn't tape it up before coating, but made sure it was back to bare metal before putting it back on.

I'll have a look tomorrow if I get some spare time, and lob a video up aswel.

Cheers.
____________________
Joe: I don't wish to floccinaucinihilipilificate your choices, but the best word in the world is gaylord.