Got one for the books. 08 zx14 loses clutch lever feel any time you throw it on her in any gear.
Lever feels just like air has entered the system,in fact when i bleed it the system does have air in it.
Feel comes back and i can ride off like nothing is wrong. Here is the weird part. There is no sign of leak anywhere in system.I have replaced every part of the hydraulic system on the clutch,master cyl, twice. All new OEM.
I mean every part from m/cyl to slave even the push rod. Take it out ride easy and it runs fine, but poor it on her and after 1 or 2 gear changes same thing lose lever feel and clutch again as if the system went dry instantly.
I shift it without clutch or with clutch same deal, pull over, pump lever 3-4 times,bled at slave or m/cyl and feel comes back and air was present.
Ride off like never happened. I have measured/marked res fluid level and never lose enough to measure Except of course when i bled it. There is absolutely no wet,or damp spots at any point in/on system anywhere. Nothing!!!
Customer bought bike new in 09 and its always had this problem, and kaw was no help all thru warranty.
Guy was overseas 2 tours so bike sat but hes retired, now back to riding it and the problem persists!
The bike has stock levers, hell all stock except for brocks ex. I am at the point where honestly have no idea what the hell is failing.
I even pulled the clutch out of one of my 14's (Basket,inner, p-plate, pack, rod assembly) hell u get the idea.
How about it Hub, go deep son its one for your brand of brain speak,LOL. Seriously anyone ideas is appreciated .
Thanks, Bill.................

Damn....

i bleed it the system does have air in it

If you're bleeding the system, and it has air in it. No offense but the problem doesn't seem too much like a mystery to me. Sounds exactly like a system with air in it.

Maybe the issue is you're not bleeding it correctly. If you replaced everything, you have to bleed from the reservoir to the master cylinder. Then bleed to the slave cylinder. If you're not doing this, I guarantee this is your problem 100%.

Gotta be that air in the upper cavity where the other nipple is. If it works and then signs off = air in line. Maybe you are shooting the same air down the line. The master has its own bleed nipple. Are we working that nipple? That's, take an 8mm box end wrench, wad up the nip with a paper towel, open the nip and pull the lever in and close nip. This is one bleed throw of the lever is all it takes. Pump up the lever and see if it tightened up or grabs sooner at the perch than at the rubber grip.

Billeason, I'm assuming you have checked all the hoses as we'll.I had a hose that looked like it was "sweating". It never leaked to the point that it dripped but enough to allow air into the system. Never noticed the pipe whilst riding only one morning when it was warmer in the garage.
Hub I have a question to the bleeding technique. I always attached a clear pipe to the nipple and pumped, then held the lever under pressure and opened the nipple with the fluid going into a jar through the pipe. I can see if bubbles come out. Then after closing the nipple pumped again. And repeated if necessary. I see your technique is different. Is this a better method for clutch bleeding? Just for the nipple on the lever or both?

I'm a little different than most. No sucking tools, just the lever as the tool. Break the nipple open - pull the lever to the grip - close the nipple before reaching grip - release lever - test action by a few pumps.

Bill, if not the master nipple and that is no joy [see if that's bubbled again], then back to the banjo and go old style. I want to see the pads. There is no cocking of the pads having a V wear with a straight pad about to have the thinnest pad touch the backing to disc? See how that may be cocked at the pad to disc to fork leg hanger?

The next one is, did we alter the polished out, machined finish? Did we remove that finish inside of the master when you rebuilt it in any way? Did you see any gouge marks, make any nicks on the inside of the rebuild? Do we have any bumps in the lines up and down each line? All rubber is uniform, no kinks, nothing bulging> rubber wise.

Hub he's having clutch problems, not brake problems.

Don't get old. Back to the same questions at the master, same old style tricks work on both. Forget pad check... For another day.

This isn't complicated. The service manual states how to bleed these hydraulic systems. Get a service manual, follow instructions.