Clutch plates dry. Built engine.... How?

Well this is the second weekend in a row screwed up by a slipping burnt up clutch. Things done. Been through 3 clutch sets already. Slack set right in handle and adjustment locking but. 3-4mm free play in lever. Plates soaked. Hell plates has oil poured over them and still slipping. After coming off the track after one lap. Plates dry already.

Bike is a FZR400 with a 490 kit in it. Engine was just built and started burning up clutches before the break in was over. We even pulled the cover off and started the engine and watched. Nothing was being thrown on the clutch.

 

Raced 400s for ten years. Never had this issue, although the YZ80 clutch pack was always woefully inadequate. Is there an issue with overall oil pressure maybe?

 

Doesn't seem to be. It's one of Speedwerks 490 kits. 400 Crank.

 

Stiffer springs is all you can do, unless there is something (perhaps heat expansion combined with rough milling/casting/burrs on them or the basket/hub) causing the plates to drag/stick, preventing full movement.
As to oil, 99% of it gets tossed off from centrifugal force so they are not really all that "wet", other than when you soak them when new.
Experience with a dry "kit" clutch taught me that new springs every weekend more than doubled the life of the plates no matter how many times (or how hard) we launched, so if you just replace the plates and not the springs after the first failure, I would look there and in any case get stiffer springs.

 

I tried stiffer springs also. This is what it looks like. Basically tried replacing everything we could, new fibers, new steels, abd springs, adjusted per the manual, plates completely dry when coming off the track and slipping while on it.

 

As to the oil on the plates, they will be dry, that's normal for three reasons two of which are normal.
First the basket never gets near the liquid level in the sump, second any oil you put on them gets slung off and third, the excess heat generated from slippage cooks the remainder.
I would add an extra steel plate (so you have two, back to back, to increase spring pressure.
Lastly, if you ain't running OEM plates...shame on you...the aftermarket sucks.

 

I am fairly certain that the FZR400 oils its clutch through the input shaft . Check that the oil port in the transmission input shaft isn't clogged with shit. The clutch receives its oil from the input shaft, which lubricates the clutch bearings and is then directed to the plates. Because the port is small an at the end of a seal shaft I have seen them get clogged with swarf over the years. The shaft needs to be out of the cases to clean though. Also if incorrect spacers/washers get used in the clutch assembly that can cause oiling issues. On some models I have increased the port size, it will take a carbide drill though, those input shafts are hard shit.

 

I'm pretty sure it don't but I can't put hands on the bits to prove my doubt so for the sake of discussion, how would the plates get oil if you run a kill switch for shifts?
And if so the lever only gets pulled before and after the race and most if not all of the oil placed there by man or oil pump will get squeezed out and slung off?
My point is that oil is not a factor in his pattern failure issue.

 

Oil pressure is based on rpm and the relief valve, not shifting. Oil pools inside the clutch assembly until the plates are lifted. Quick shifter's (or shifts) do not aid the lubrication of clutches. Assemble a dry stack in a clutch basket, and then remove. Do the same with a wet stack. Notice a difference? The oil is a key part of the clutches ability to "lock up". Surface tension... most OEM's don't design a true dry clutch.

Tunersricebowl- his entire stack is dry... DRY... It is not a dry clutch, it is not splash fed. They are burning up for a reason, and not because it is 20 year old technology. This is nothing new.

 

How does the oil get between the plates if the lever is not pulled?
Pressure on plates will squeeze almost all the oil out of the friction material and centrifugal force will sling off the rest.
If oil had any role in plates sticking together, dry clutches would never work.
The plates burn because they overheat due to slippage which is not caused by a lack of lubrication but rather by not enough clamping force, reason for which is yet to be determined.
I've seen wet clutches installed dry and did not hear later that dry install killed the stack.

 

there will be a lubrication flow diagram in the manual. check it and then check your motor correspondingly. something ain't right.

- jim

 

Well the other question I have is, what would cause a brand new set of clutch fibers, steel plates, and heavier springs to start slipping as soon as they are installed? As in put them in, take off, slip. Lever adjusted correctly. Could it have fried the pressure plate? Basket? What? I figure this is a oil delivery issue but if I can put another known good basket and pressure plate tomorrow for the race, and make sure it is oiled, then I can at least get through that and finish a race. Then deal with what it is after.

It is just very frustrating to have a brand new refreshed engine and have this issue before the break in is even finished.

 

Hmmm... it does kind of sound like something on that shaft is not shimmed right.. For grins put all the plates in but ONE steel... the outer pressure plate will then bottom on the center hub.. (yes put the springs in).. check the clearance by stacking some feeler guages.. is that thickness less than the thickness of the plate you left out..? If not, then there is your problem...

You must replace the springs, any time the clutch got that badly overheated, as that may of softened the springs... cheap insurance...

Good Luck...

Ron

 

Dustin,

When you say that the lever is adjusted correctly I assume you mean the lever at the bar.

Have you checked the shift rod adjustment? I run a YZF600 which has a similar clutch ststem to the FZR400 and there is an adjustment that can be made at the point where the cable attaches to the clutch "push lever" that is critical in setting up the clutch. I have had to adjust mine a few times over the years and a very small adjustment can make a big difference in performance and clutch life.

If you have not, you will find a rubber plug on the countershaft cover that allows access to the adjuster. Once the cap is out you will see the adjuster screw and lock nut.

Break the stop nut loose and back the adjuster screw out until it turns free.

Turn the adjuster in until you feel it start to push against the clutch springs and then back off 1/8-1/4 turn. (check service manual. I am guessing as my manual is 5000 miles from my current location..)

Set Lock Nut.

If this is a critical adjustment for this system. No ammount of adjusting at the lever will help if the adjuster can not fully release the clutch. DAMHIK

 

True that, but if the push rod lacks internal free play, it will in pretty short order get friction welded to the push ball, and not much later the ball will weld to the pusher, and that is easy to check just by looking at the pusher, ball and rod end.
Even if the rod/ball/pusher ends are not friction welded together, the signs of heating and metal melting will be an easy tell.
Got to be a stack height or parts compatibility problem, barring damaged/worn hub+basket slots OR the outer cover being "clocked" wrong.
Is this one that MUST be aligned properly in order to seat fully against the first fiber?
I had a Suz clutch fail in just the same manner because the tiny fish failed to point out that ONE of the steels was .5mm thicker than the rest so my box full of OEM bits kicked my ass until somebody asked if I had the special plate installed...of course I did not but the "thousand miles from home" cure was to run two stock thickness steels.
It's all about the clamping force, wet or dry.
Oh and those springs are dead and buried.

 

That is a mechanical issue. I agree on checking the stack or simple misassembly.

 

All those little gaps between the fibers...

I always soak new plates overnite in a tupperware container of the same oil I use in the engine the plates are going into.

 

Never could understand why?? It isn't as though the plates actually "absorb" the oil....

 

Unfortunately I know more than I would like to about the 400's POS oiling system. (trying to keep 90hp crankshafts alive) If I had to guess, your clutch pushrod seal (left side of engine) is installed too deep. This would block the oil feed to the primary shaft. The seal needs to be flush with the outer edge of the engine case. Or, there is sealant blocking the oilway that feeds the shaft, which would mean it's time to split the cases. Your clutch needs oil to stay alive, and it is obviously not getting oil.

 

Fun trivia question...

What motor has a DRY clutch that spins in an oil bath??