New Levers, New Problems - Need help

[SynysterCT]

I will preface this by saying this is my first bike, but I am generally very handy and have no issue working on it.

I recently picked up some new shorty brake/clutch levers. Install was a breeze, but I am now having issues with my front brakes.

I figured since I needed to bleed the lines with the lever change I would change the fluid as well. I bought the bike used this year (its a 2009) and have no idea the last time it was done. Changing the fluid and clearing the lines was not difficult (as you probably already know).

The brake pressure felt correct with the new lever so I took it for a spin. About 10-15 minutes in the lever was getting more and more stiff and I could feel my front brake grabbing even though I wasn't touching the lever. It got to a point where I had to pull over because it was practically locked up. I pulled out my screw driver and removed the front brake lever entirely. This let the plunger out and released the lock up on my front rotor. I rode the 2 miles home with no front brake but at least it wasn't locked up.

Reinstalled the lever when I got home. Very stiff. Bled the lines again. No air whatsoever. Fluid is new and full. I cannot figure out why the pressure would be building like that. I compared the contact points of the new lever vs stock and they are identical as far as I can tell. Anyone have any ideas?

Thanks in advance.

 

[SynysterCT]

**UPDATE**
So I think I fixed the problem. It seemed that the pressure was building up in my brake lines and not being released. When the lever was removed the pressure was then released and I could ride just fine. That got me thinking... The detent that the lever moves must not be releasing fully. I got out my calipers and measured the detent cavity in both my new lever and the stock one. The stock one was about 2mm deeper than the new lever. I drilled it out to the correct depth and smoothed out any burrs with 400 grit sandpaper. Took her out for a 20 minute ride and the brakes were smooth as could be. I'll keep an eye on it and report back if there are any issues.

For anyone looking at new levers.... I bought these... Make sure you check the depth of the plunger cavity.

Blue CNC Shorty Brake Clutch Hand Levers Set Yamaha FZ1 FZ6 FZ07 FZ8 FZ09 XJ6 | eBay

 

[lizardsbba]

The brake master cylinders have a couple of ports, one of them is a pressure relief port that allows fluid to flow back out of the lines into the reservoir. If the plunger is pushed too far into the cylinder it blocks off the bleed port and will not allow fluid to return. This causes pressure in the lines to continually build each time you press the lever. Properly adjusting your brakes is a good step to take when doing something like this. Good catch of the measurement of the detent.

 

[Bert-Aus]

There is a thread about this issue somewhere on here covering this in more detail.
Essentially the ebay levers are problematic.
Sorry I can't find the thread due to being on mobile but it dates back a few years

Sent from my C6903 using Tapatalk