"Grabby" Clutch Engagement

[enels57]

Has anyone else experienced an intermittent  "grabby" clutch on this bike?  
 
It is more likely to happen when I get through my subdivision and enter the first main surface street....probably about 4 minutes after starting it up.  I usually let it warm up about 1-2 minutes while I'm putting my helmet on.  I have had it happen about a half dozen times in that situation... after sitting at the stop sign for maybe a minute I let the clutch out and it is like the opposite of having anti-lock brakes...it pulses a few times somewhat violently before grabs all the way.
 
At least twice it has done this when it has been completely warmed up.  Both times while practicing getting off the line quick... getting on the throttle and clutch pretty aggressively.
 
The other zillion times have been a non-issue.  Ah...the thrill of troubleshooting an intermittent problem... 
 
I have never had any other bike I've ever ridden do this.  I'm at 11,500 miles currently.
 
Thanks!
 
 
 

[mjh937]

I am sure you have already checked this, but is the oil level okay?

[bmwpowere36m3]

Clutch free play adjusted?

[rick]

Sounds like what you are describing is called clutch chatter. Lots of causes if that's the case. But if this was a car clutch, i'd say you've been slipping it too much and it's been overheated to where the pressure plate has developed hard spots.
 
But - easiest thing to check is your cable and lever. One or the other might not be working smoothly - lube, check for frays etc. Make sure you have enough free play in the cable to allow the clutch pack to fully close with the bars turned full lock either side.
 
What kind oil are you using? If it's not designed for a wet clutch, a switch (even just a different brand) might help. My Aprila's clutch was far smoother after a switch to Amsoil from several other brands of semi-synth motorcycle oils.
 
Then there's the clutch plates. You might have a warped steel or glazed friction disks or maybe a worn spot on the drum or basket hanging up the pack. I'd think you might have some slipping as well if that was the case. Only one way to know if the other things won't fix it - pull it apart.

[enels57]

Great information all...thanks.
 
Oil level is good but when I get it back from a dealer service it is always overfilled...I don't get those guys, you think they would know better? (I digress)
 
One thing I wonder about is this, they use yamalube in the shop but when I do oil changes between services I use Rotella T. Would those two different oils maybe not play nicely together? Life would probably be easier if I just quit having the shop even do oil changes at 4,000 mile service intervals and just do all the oil changes myself using the same oil every time.
 
I think the free play is good and the cable is good.
 
It shifts fine 99.9 % of the time...just a weird intermittent thing that happens usually when it's not all the way warmed up. There have been three exceptions to that though...
 
 
 
 
 
 

[rick]

Lots of guys successfully use Rotella T w/o issue. It's probably a far better oil than Yamalube. Forget about taking it to the dealer you see how careful they are not with your bike. With the money you save in labor, step up to the T5 semi-synth or even T6 full synth. The chatter might just go away.
 
I suspect you have some glazing from some hard launches. This clutch is probably not exactly heavy duty. The springs are likely just stiff enough to allow the clutch to work reasonably well w/o the lever pull being too stiff. Stiffer springs might help, - maybe even the old trick of adding a washer under bolt head for each spring.