Ok, g'day guys n gals...
My name is Macca, and I love ZX14's...
I just got my dream bike 2 weeks ago and it will be getting rego next week but I have come across an issue.
As the title implies, My front brakes are slowly locking themselves on.
Now, the bike is a repairable write off from Vic, it had a broken brake lever so I bought a new one and changed it over. I rode into town for a pit pass and rode it home again no worries.
The next day I rode it in again for another inspection and a couple mins from home the front started to feel heavy. I pulled the clutch in and she pulled her self up to a complete stop without me having to touch the brakes.
I cracked the bleeder on the brake master to let the pressure out and locked it up again and it was fine for the rest of the day.

I suspected it was caused by thermal expansion possibly due to moisture in the fluid, so I put new fluid and bled the brakes up a half million times. They worked fine for maybe 10km then started to lock themselves on again.
Same deal, crack the bleeder to relieve pressure and lock it back up.
Over the last couple days it has been getting worse, with the brakes locking on within 1-2km of home and the same after cracking the bleeder. It even locks on over night when the bike isn't in use.
It was suggested the return valve in the master may have been blocked with bits of rubber from deteriorating lines so I dismantled the master, blew it all out with compressed air and made sure it was spotless. Reassembled wet and re-bled it again with new fluid. (Didn't find anything inside the MC)
Problem still persists.

Side note:
The only damage to bike was scratch fairings and broken lever.
The bike is a 2006 ZX14, non ABS.
No fluid leaks anywhere and the brakes operate as normal when applying and releasing them.

Any help would be much appreciated.

Welcome to the forum.
First thing, did you replace the brake lever with an aftermarket one? Some from China have the
pivot pin hole drilled too shallow. Keeps the brakes slightly on. Check that first.

Mad

Welcome!

I would pull the calipers off pull the pads out and wash with soap and spray brake cleaner to get everything nice and clean so so can inspect the calipers. Push the pucks back into the caliper and make sure the seals are good and clean and tight. Reassemble and do a full and complete bleed of front and rear and report back.

AS Mad dog has said cheap after market levers have had some know issues

Sorry for late reply, Was on the MRA toy run. It was an after market lever from a local yamahaha dealer. Would drilling the pin say 1-2mm deeper fix the issue if that was it? Considering I bled it up with the new lever on and they worked fine for the most part, I just cant see how that would do it but hey, I am in the newbie section ;D

OK, I had a theory to test out the lever as being the cause. I have taken the lever off so that the pin and plunger are completely out and not being held in a little as the after market lever does. With removing the lever the brakes released as expected. Now I just wait to see if the brakes lock on again whilst the lever is off. If they don't, then I know the lever IS in fact the issue and I can fix it accordingly. If the brakes do still lock on again, well... I guess I look else where.

2 bikes that I have put aftermarket levers on did that. Hope that is the problem.

* Last updated by: lytnin on 12/2/2018 @ 2:58 PM *

UPDATE!!!!
FIXED!!!
Looking at the levers you wouldn't notice any thing out of the ordinary. But the little steel roller inside the lever has a hole in it for the master cylinder pin to slid into. Was no way of telling this straight from the packet.
Note, this doesn't have to be disassembled to spin the steel roller around. You could probably spin it with a pointy object. This is just how I found out about it.
This all might seem odd to cause an issue, but due to the pin not sliding into the roller hole, the master cylinder would always be under pressure from the lever and cause the brakes to slowly apply themselves and the valve at the other end of plunger to be closed under force.

This is how the roller looked straight from the dealer. (hoping this will add the pics).

By knocking out the brass Bush, you can separate the 2 parts of the lever and allows you to spin and remove the steel roller

The master cylinder pin should slide right in to the roller without the need for releasing the bleeders.

Great news. And great pictures to help those who run into this problem in the future.

Mad