Slipping under full load - adjust or replace clutch?

I was out tearing around on the bike and noticed in first and second gear at wide open throttle (7K rpm) I have to back off full throttle or the clutch slips.

I was reading Rick's excellent write up and thinking that my clutch could use some adjustment. But then there was one point where he mentions that if you get slipping under full load, the friction plates are gone.

Now, to add more to the equation...I am using conventional Rotella T 15w40.

So there are three things possibly going on here:

1) Clutch simply needs adjustment and is not fully engaging and is only revealing itself under full load at WOT.
2) Friction plates are fried...rebuild the clutch.
3) Its the oil...get a legit motorcycle oil (I know Fitz, I know)

What say you?

 

Change the oil. Easiest thing to try, and it does not "have" to be changed again if you do the clutch later.

 

do #1 so you can ride to the bike shop to buy #3

 

The Rotella 15W40 most likely isn't the cause (although I wouldn't run it, as you already know) more likely it's simply clutch time.

How many miles on the bike? The original clutch is pretty much all done at anything over 20K depending on "thrash" factor; however:

the clutch doesn't have to be worn out to start slipping. Remember, the friction plates are a collection of tiny brake pads, dipped in oil. When one of these bikes sits for a few years the friction pads on the side of the clutch NOT submerged in oil (or the whole clutch if it sat on the sidestand) dry out and become more like little petrified linoleum pads that really can't grip anything anymore, and start to crumble. I didn't really go into friction plates in my clutch article http://xjbikes.com/Forums/viewtopic/t=29541.html because it's aimed at the owner with a stack of new friction plates and springs in hand, ready to rebuild their clutch.

New friction plates, springs, and a gasket and you'll be good for another 20,000+ miles. If you want to get all hinky replace the cable at the same time for that "brand new clutch" feel.

 

Make sure the cable isn't binding ie check the actuator at the engine end is actually free to return cleanly

 

i've used Rotella for years with no problems, it could be adjustment but most likely it's plates and SPRINGS, don't over tighten the bolts

 

Thanks folks. I figured that was the case. It rides around just fine and pulls to that RPM at full throttle with no issues. But the bike did sit around for probably 8 years before I got it and actually have it to a fairly serviceable state.

Fitz, your write up looks amazing and actually not complicated at all. Glad the clutch is exposed to the world and pretty easy to service.

Polock, I never had a problem with Rotella either on my other bike. I just know that I couldn't rule it out completely in this case.

Now...I just need to check my wallet...

 

Your clutch is easier yet, you don't have the tabbed plain plates or special friction plate with the "clutch boss spring" to worry about.

I'm getting GREAT performance out of the clutch in my '83, which consists of "aftermarket" friction plates and OEM springs with refurbished (Scotchbrite) plain plates. I got my parts from chacal of course.

 

Before you do anything else make sure there is about 1/8" free play at the lever.

I've got one in the shop now where the guy said it was slipping under full throttle. He assured me he had some free play.

It was almost 8:00 PM when he dropped it off and he'd forgotten the key so I wrote it up and we both left. Next day I looked at it and I had to back the adjuster off 1/2" to get any free play. It's a wonder the clutch grabbed at all.

I suspect when I get the key I'll find he just needs tires.

 

Thanks Fitz and Carl. I will do the clutch adjustment tomorrow (maybe tonight) based on Rick's write up and go from there. I can't tell if I have free play at all honestly. I am a hamfisted fella so I just grab and go!

Thanks to all!

EDIT: I did notice that down at the clutch cover, there is not a whole lot of movement at all when the lever is pulled. I guess it translates into just about less than a quarter inch of rotation from eyeballing it.

 

Not sure what a quarter inch of rotation is, but I measured mine at the bottom end of the cable, and there's a bit over 1/2" of cable movement from fully released to fully engaged.

 

When you start to pull the lever the only resistance should be from the return spring on the clutch arm. When the gap between the clutch lever and its perch is about 1/8" it should start to move the pressure plate and you can feel the extra force from the actual clutch springs.

 

Lubricate the cable. I replaced my clutch two years ago. It was cheap and easy. After the job, it still slipped. I lubed the cable and it made it better. I replaced the cable and have not had the problem since.

Good luck

 

I just did the adjustment to the clutch per Rick's instructions and no more slipping! Carl, I think you were right. Definitely need to heed dirtymaxim's advice and lube my cable too. Same for the throttle cable.

Thanks folks. I am definitely not afraid of changing out the clutch though after this experience.