Clutch slip - ever tried a little more pressure?

[MarkinAR 14]

Passing thought here and thought I'd pitch it to the group for debate.  I'm working through a Kodiak which is basically a Big Bear in a heavier bike and the same as about anything Japanese made for 30 years as far as clutch function and design goes.  This Kodiak is odd though in that the centrifugal clutch slipped a bit with good clutch material remaining and the main clutch pack seems to slip a bit as well at high RPM but also still has good clutch material left.  Much like the Kawa race bikes from what I've read.  Do you think it's an option to add a thin washer to the pressure bolts to put a bit more pressure on the main clutch and force it to use a bit more of the clutch material before having to replace?  There's seriously like 50% of fiber left on the main clutch pack and it seems silly to replace it all before it's truly worn down.

[MarkinAR 14]

No opinions here? I'm surprised. 

[Frank Angerano 529]

I didn’t even see this post for some reason.   I don’t think it would work since the washer you could only really fit in would be a 16th of an inch think ? How much grab do you think you would gain ? And how long would it last anyways? 

[MarkinAR 14]

Given that the clutch packs are maybe 1/8th of an inch thick and those have lasted 26 years, i would think 1/16th of an inch might buy a couple of years.

Just thinking outside of the box.  It just doesn't make sense that it would be slipping with 50% of clutch material left; but it doesn't seem to be all that unusual.  Just seems like odd planning on Yamaha's part.

[Frank Angerano 529]

Yeah well planning is not always on the forefront with these people. If you go back and look at one of my threads on my Bayou, there was a neutral safety switch. Worst design everrrrrrrrrr! So I could see it on Yam behalf also.  

[MarkinAR 14]

I've read the kFX450 wears out at 50% and you need to put stronger springs in it so it doesn't do it again. That's where I'm getting the idea that maybe the kodiak is the same. The 220 bayou though would grab fine with just enough fiber remaining to cast a shadow. Crazy how they are about all the same but have little behavior quirks. 

[Frank Angerano 529]

Listen man I’m all for that idea so let’s get after it and throw some washers in. Be sure to use thread lock so nothing comes loose! 

[XWrench3 12]

if it is the clutch PACK slipping, then yes, a set of washers may help for a while. stronger springs would be a better choice.  it also could just be improperly adjusted.  but if its the centrifugal clutch slipping,  you may be out of luck. 

[MarkinAR 14]

4 hours ago, XWrench3 said:

if it is the clutch PACK slipping, then yes, a set of washers may help for a while. stronger springs would be a better choice.  it also could just be improperly adjusted.  but if its the centrifugal clutch slipping,  you may be out of luck. 

Centrifugal clutch I regrooved and worked the drum smooth. Seems to pull fine until you hit WOT so I'm pretty sure it's a clutch pack issue. Thanks for the input. I'll try readjusting when it's back together and if that doesn't work shim the springs a bit. 

[MarkinAR 14]

Mystery somewhat solved. The threads in the case for the adjustment screw are completely gone so adjusting is best guess based on feel. Without threads it's also not keeping pressure on the clutch. 

[Frank Angerano 529]

Good work detective! Dam that sucks, so now what to do ? 

[MarkinAR 14]

Gonna pull the side of the case again and inspect. Hopefully I can drill and tap a size up and use a bolt nut combo to replicate the current function. Not sure as I've not looked at the way it's made but surely I can replicate the function. 

[Frank Angerano 529]

Probably can be drilled out at tapped just go slow and lots of oil.  I would also stick with a metric bolt and def thread lock when you reassemble.  

 

[MarkinAR 14]

Not sure thread lock would be a wise idea since it would still need to be adjustable. Seems this is going to be a rig job....

[Frank Angerano 529]

I agree but I would not want it coming loose! Get it tight and where you need it and let it be! 

[MarkinAR 14]

So the clutch still wants to slip a bit if you throw it WOT in middle gears but doesnt slip if you ease it to WOT. Probably centrifugal clutch. But anywho, here's a couple shots from yesterday's ride.