Really, the best way to figure out is to replace each part bit by bit with OEM. If you're using aftermarket, you could be getting more than one bad part. As others have said, even a little binding on the brake lever can make it start to lock.

 

This is a known issue with the eBay cheapo brake levers. I have personally seen it occur on several bikes over the last two to three years.

The lever is not quite the correct size, it prevents return flow and as the heat increases, it locks up. Only solution I've seen was scrap them and get better levers or take a Dremel to 'em.

Another thread

And Another

 

I think I will just dremel my current lever to make sure that's the problem, which is really all it can be at this point. Should the lever JUST touch the plunger? I'm just not sure exactly how much to take off.

 

A stock brake lever is hella cheap, why do people go nuts for anything ebay/chinese made????

 

Dealer has 1 left in stock, going to pick it up after work. Will report back.

 

Well chalk another one up to cheap levers. Picked up an OEM lever and haven't had a problem since. Thanks for your help fellas. Now I've got to get rid of the entire brake system that I bought thinking that was the problem. D'OH!!

 

Glad it's now working correctly for you. I too have some cheap Ebay levers (carbon fiber levers) and haven't had a problem with them, but now I think I might just order some OEM levers and go back to stock.

I had to replace my levers when I went down 2 years ago.

Well, happy safe riding!!!