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Clutch or Clutch Cable issues

7K views 35 replies 6 participants last post by  tones160 
#1 ·
I have a 2008 R6 race bike that I have noticed some issues. Over the weekend at an event the clutch lever was becoming more loose as I rode the bike. I have seen no signs of the clutch itself slipping yet through the powerband. It did seem to accelerate slower from a dead stop, but the power seemed to be there at higher RPMS.
I was also getting some miss shifts and false neutrals only on down shifting. I have a quick shifter so I believe that is why there was no issue on the upshifts. I would tighten the clutch cables between riding and it would shift fine again.

Some suggested replacing the cable but unless it is frayed there is no need as it shouldn't ever stretch. So that leads me to the clutch itself. I was going to pull the plates out and mic them and see if they are within spec or look for any other clues, should anyone have any tips? What should the thickness of the overall stack be versus the individual plates?
 
#3 ·
That was my thinking but I haven't noticed any slipping yet.
Do we have access to an online manual on the forum? (I'm going to have a look)
Any suggestions on the best place to get a clutch kit?
 
#5 ·
Thanks, I had someone mention replacing the cable but I was also told that the cables don't ever go bad unless they are frayed. My tuner recommended the OEM kit, if I needed it, but I'm no opposed to a aftermarket one if it will perform the same.
 
#7 ·
Order the clutch kit before you disassemble. Personally I would replace the springs as well. 8yrs is a long time. EBC comes with some. Of you can shim the existing ones. Again = your preference.
You'll also want to set the slipper up to your style. You can have 1 full y spring with the tabs cut off the other 2 or a variation of combos.
Check the basket real close for "indentations" between the fingers... usually causes chatter or weird engagement issues from the fibers. .
Lastly check the sump and oil pickup are clean. Debris falls down into there...especially worn clutch material. Could be enough to clog (cavitation) your oil pickup reducing oil pressure.

Have fun reinstalling the clutch cover...lol
 
#9 ·
My bike is a 2008 racebike with about 8k miles on the odometer.
I was told the built motor blew and was replaced with a very low miles 09 motor from a totaled bike. I believe this only because the wear metals in the bike for the first 500 miles I had it were high enough to indicate that it was low miles. As I got miles on the bike the wear metals leveled off. 1/2 season later and this is the issue.

I have been replaced clutches before so I know what they feel like when they are going out. This gave me no indication of that but I have never had a clutch lever become a little looser each time it was ridden. I probably adjusted the lever 2 times over the weekend races, which is about 300 miles.
 
#11 ·
Inspected the cable very closely. No bends or fraying were to be found.
I'm going to have to get into it and measure the plates. I'm surprised as this motor is fairly new, so replacing the clutch wasn't even on my radar and I am usually proactive with the maintenance. Does anyone know if the clutch cover is actually a flat gasket vs an o ring? Wondering if I have to get one ordered, should the clutch not be the issue.
 
#13 ·
Flat Gasket. I pulled my cover off without replacing the gasket but just be careful not to damage it. Still not a bad idea to order one anyways, there pretty cheap and if you don't need it now you might need it down the road. At least that way your not waiting for a gasket should it be damaged taking off/replacing the cover.
 
#14 ·
Cool, I was just trying to avoid having 2 of them.
(order a single one, then order the clutch kit if need, which has one also. )

Thanks Guys, I will get into it this week, hopefully I can get it figured out but if not I will be back soon enough.
 
#17 ·
the overall clutch stack measure within the manual specs. The first 2 clutch and fiber plates measure over the STD spec in the manual but the last set of plates are below standard. The last couple of clutch plates have these burn marks on them. Before you get to the middle of the stack there is so more signs of wear. I'm thinking this few things justify a new clutch kit. But if there were no wear signs I would think it is still too close to spec. Are the wear marks normal for a clutch that is about to slip or is there another underlying issue?
 

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#21 ·
That's what a burnt up clutch looks like. Keep riding it and soon it will be slipping so much it's un-rideable and when you take it off you will see that all the steel plates look like that.

Just like I said in the first reply, your clutch is beginning to slip and fail.

You are really overthinking this, just get a new OE clutch kit from Partzilla for $125 and all your troubles will be over.

Replacing clutches is pretty routine maintenance on a RACE bike. Race starts are very, very hard on the clutch. I never go to the track without a spare clutch kit in my spares bin.
 
#25 ·
I guess you have bought this before then? I sent in an email. It didn't list all that but it is the "kit" which Yamaha list as having everything under that part #.
 
#30 ·
Thanks again everyone for all the advice and help through this.
I ordered the Clutch Kit and a new Clutch Cable just to be on the safe side. I didn't want to find out that the cable was causing the clutch to slip any.

I have to say I am a bit nervous as to if everything is done correctly, but I read the manual, soaked the clutch for 30 mins, checked the stack prior to install and made sure all the part #'s were correct.
After I got it all installed the lever didn't have any feedback. After going back and checking I made an adjustment to the cable spring arm at the bottom of the cover. I didn't think it would need to be realigned from what I thought was the factory position but I lined the Triangle up with the Dot. This gave the lever the feel I was looking for.

I adjusted the free play in the lever and gave it a little spin around the block. I couldn't ride it too much with being a racebike but I will know more after the weekend.

With the bike on the stand in 1st gear and the clutch pulled in the wheel spins very fast. I do not notice it pulling the bike at all when I put it on the ground but I fear it could be dragging a bit? Is this normal until the clutch breaks in? Is my tq wrench off a little when I tightened the springs?
 
#32 ·
When you say Threads showing are you talking about the free play?
I adjusted it at the low side per the manual @ 10mm. I can tighten it up, but I would think it would feel almost too stiff then.

The wheel is spinning much faster than I have ever seen. Nothing noticeable when just sitting in gear with the clutch lever pulled in. The lever does grab early when I take off.
 
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