clutch failure

I need advice on what to replace in my clutch on a 07 yz450. Here is my problem.

I went to practice yesterday and my clutch was slipping all day. I didn't notice it at first (I thought it was wheel spin). After about 3.5 hrs of hard practice I notice all my play was out of the clutch lever. I adjusted it on the track then no play again. I had to loosen locknut to get play back in the clutch lever. I went back out on the track and the clutch didn't slip anymore, but I definitely backed off the throttle alittle. When I got home I could smell a burnt smell around the bike. :confused:

I took the cover off today and I need some advice on what I found:

1. clutch plates - the plates (metal) are black!

2. pressure plate - some discoloration on teeth (where the plate, clutch basket, and plates connect) but no grooving. I do see small grooves where the springs sit in the pressure plate.

3. Inner Hub - discoloration and slight grooving(can't be felt but can be seen)

4. Clutch Basket - has grooves that can be felt with finger. From side looks wavy.

Anybody else have this happen to them? I'm so pissed off. :confused: I usually maintain the 450 after every ride but my son started racing 50's and the last three rides I haven't had the time to look my bike over. I have been just cleaning air filter, changing oil, and lubing chain on the 450.

Should I replace all? Can I get buy with just replacing the clutch basket and plates now? Then replace pressure plate and inner hub this winter. In other words can I just piece a new clutch together? Can I run clutch until total failure or is it an asap situation?

Let me know what you guys think.

I had some similar issues with my 250F which actually led to me getting a 450. I would replace the worn parts with OEM sooner than later. I tried the piecing it together strategy and it did me no good. Just kept burning up fibers prematurely.

One questions though... Within 3 or 4 rides, what else besides cleaning the air filter, changing the oil and lubing the chain must be done to a 450? My guess is that the clutch was just ready to go, probably due to the basket needing replaced more than anything.

I usually check clutch adjustment, throttle freeplay, and take a 10mm/12mm wrench over the bike also. I was thinking the clutch may have failed because I neglected to check clutch freeplay for three rides.

Am I wrong? What else could be the cause? I don't see too many tt'rs complainng about the clutch on a '07.

Well, clutch freeplay should be checked before every moto and throughout it as well. I always wiggle the end of my lever while I put to the track entrance, just to make sure I won't be slipping it out there. If you didn't have any play at the lever and rode it like that for a few days, then yeah I would assume that would heat up and slip a clutch relatively quickly.

has anyone ever seen the springs wear grooves in the pressure plate?

Yes, I've seen the grooves from the springs on several bikes. That clutch of yours... I don't think there's anything you could have done. You probably had a plate hang up or something like that. But you could have stopped sooner had you known. The grooves in the basket and on the hub can be dressed back up with a file if they are not too bad. You have to judge what's too bad though.

Like this?

basket.jpg

High heat caused from a slipping clutch is all that I could imagine could do this when I saw mine. Notice the clutch boss grooves in the pic on top. Again, I kept replacing things one at a time with questionable results.

If I had to do it over again, I would have simply replaced everything that was borderline the first time and saved myself both time and money. The OEM pressure plate and clutch boss are relatively inexpensive compared to the Basket. If you're going to pony up for the basket, go ahead and get a new pressure plate, clutch boss and new steels/fibers as well.

You know the saying "a picture is worth a thousand" well your pics answer some questions for me.

My inner hub/clutch boss isn't grooved as much as yours but my clutch basket looks much worse. Your pressure plate and mine look identical.

I guess its time for a new clutch. I just don't think a new bike should have clutch problems so soon. I change my oil every other ride and after every race. Oil filter every 2-3 rides. GGGRRRRRRRR!!! :confused:

Thanks swaldrop.:confused:

those pic's were from my old bike... An '07 YZ250F! I felt the same way when I was going through the clutch woes. Good luck.

swaldrop,

What oil do you use? I'm just trying to figure out what caused the clutch to fail so early. A plate sticking could be the problem, but maybe oil also. I use Mobile 1 Racing 4T.

GreyRacer, any other tt'rs,

Do you guys have any ideas what would cause this type of clutch failure?

Swaldrop's pictures are exactly what I am dealing with. Since his (Swaldrop) problem was on a '07 250f and mine is on a '07 450f, I would come to the conclusion that the clutches seem to be wearing prematurely. Correct?? :confused:

I want to prevent this from happening again so I would like to find the cause.

At the time I was using Yamalube 4R. I have since moved to Shell Rotella for the 450, primarily because I have heard lots of good things here on TT about it, plus it is economical to change the oil every ride if need be. Currently I change it every other ride with a filter every 4. No problems with the 450 so far, but I have only ridden it 4 times.

Do you guys have any ideas what would cause this type of clutch failure?
The grooving is a result of the drive load bearing on the edges of the plates. Things that can accelerate this kind of wear are dropping the clutch under heavy power, fanning when exiting a turn instead of using the right gear, landing jumps under power with the wheel spinning.

Things that cause the clutch to burn out are "riding" the clutch (keeping pressure on the lever while riding) and slipping the clutch in a higher gear to avoid downshifting. If any of this happens to your bike faster than it happens to other YZF's, it's very likely your doing.

Should I replace all? Can I get buy with just replacing the clutch basket and plates now? Then replace pressure plate and inner hub this winter.
Replace the basket. Use a Hinson or GYT-R part to upgrade it. It will cost less than an OEM basket and last longer. The grooves in the spring buckets are harmless, and it sounds like the boss is OK, too. Replace the plates and springs, and be done. Hinson or GYT-R plates and springs are a significant upgrade, too.

GR,

I am guilty of

landing jumps under power with wheel spinning and dropping the clutch under heavy power.
I didn't realize that landing jumps under power was bad on the clutch.

Now that I know the cause of grooving I'll implement a solution by changing riding technique.

I have part numbers for GYT-R clutch basket and plates but I can't find the springs. Do you know a good resource for the spring part numbers?

I really appreciate the help. :confused:

Get the springs from Hinson, or use OEM.

Anything that delivers an impact or shock load to the drive train is "bad for" the clutch and everything else. Some of this kind of abuse is expected, of course, but it still adds up.

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