Clutch slipping but only at higher RPM's...

My clutch seems to be slipping but only at higher RPM's (7-8k ish). This is of course under hard acceleration and most often happens in third and fourth gears...but only toward the end of the range for the gear...in other words it happens just about the time I'm ready to shift up.
It seems like the clutch would be most likely to slip when first engaged in a gear...not when I'm almost out of it and it's been pulling hard (and fully engaged).
Is my clutch wearing out or is this something else?
This is a 1982 XJ1100J with a really big guy riding it. The bike has 51k miles and the clutch has about 25k miles on it.

 

Time for a clutch unless its way out of adjustment. Higher rpm and the faster you go is when you have the most strain on it. Your up in the peak power and cutting thru the air is worse the faster you go. You have the sure sign of a bad clutch

 

yep, that's when they slip, when it's making the most HP.
replace the friction plates and springs and be happy for a long time

 

Basically what they said, except it's at peak torque that a clutch will start to slip (when the engine torque overcomes static friction of the plates, it slips). Peak torque is about 7k rpm

Also 25k miles is a reasonable amount of time for a clutch to last.

 

Hum, makes sense after thinking about that.
Thanks guys!

 

What everyone else said. However, if wrong type of oil can also contribute to the clutch slipping. Automotive type oils should not be used in a wet clutch system. The oil used should be rated with a JASO-MA specification. If you have used an automotive type oil than it could be your problem.

 

This is false.

Most automotive oils can work fine with in a motorcycle.



Never use oil with the energy conserving label on a wet clutch, unless the manufacture specifies for it.

What matters in these motorcycles is the thickness of the oil, and the viscosity.

However, the differences are the additives in the oil between them. To be 100% honest with you ( from working at a powersports dealer ) special motorcycle oil is a complete scam for most people (unless you have a race bike). As long as the viscosity of the oil lasts doesn't change much over the span it is in your bike, you'll have no problem. Now, on the XJ series bike, automotive is a 100% perfectly ok in your bike as long as you use a non-energy conserving oil.


The reason energy conserving oil cannot be used in this type of motorcycle, is because it is an already thinner type of oil.

If you want to read more on this study,

http://www.ducatimeccanica.com/oil.html

 

It's not exactly false; XJOE550 just didn't provide much detail (but you did). Energy conserving oils can be found in every viscosity, and should not be used in wet clutch motorcycles. The starter clutch in an XJ will begin slipping when a energy conserving oil is used (long before the powertrain clutch slips).

http://xjbikes.com/forums/index.php...orrect-oil-for-a-wet-clutch-motorcycle.43702/

http://www.jalos.or.jp

The JASO MA rating (which can be found on many automotive oils) was developed precisely because of the slippage that is caused by using newer automotive oils in wet-clutch motorcycles.

Most of the automotive oils that are in stock locally are of the energy conserving type, so I have to read the labels carefuly when I go shopping.

Having said that, the OP likely needs new clutch friction plates.

 

Same oil I've been using for years with no clutch issues. RotellaT 20-50. Great stuff.

 

I meant 14-40...

 

Jees!! Broken thumbs tonight. Rotella 15-40

 

old oil will cause slipping as well
but you can buy plates and new springs for about 45 bux

 

Thanks for clarifying and filling in the blanks k-moe. You are right, I did not want get into any discussions about friction modifiers and oil formulation. My knowledge is limited to what I have read and suggested by others over the years. I'm not a chemist. Suffice it to say, using oil with the JASO-MA specification will give peace of mind. It gets very technical very quickly otherwise.
Mike, I just figured I wold throw the information to you just in case. As far as the oil you are using is concerned, that is the same exact oil I use; Rotella T 15-40W. Although it is automotive oil, it does carry the JASO-MA specification (or they say equivalent I think). Taking that into account, as k-moe and others have said, sounds like you will need to put in a new clutch and springs.

 

I think I got it guys, thanks!

 

If Mike has been neglecting to change his oil, or the bike and oil history is unknown, then I agree, try this first before springing for clutch. My 750 slipped like a mofo when I got it going, it had sat for about 5 years and the PO didn't change the oil for the 5 years prior to that. I changed it twice over a two week period. Problem solved.

 

I can tell when I need to change my oil.. I do need to rebuild my clutch at some point
but if my oil is starting to thin I will have issues going into 2nd gear
new oil, fixes the issues
Oil is cheap..

 

Yeah, but the plain plates aren't. If you are having any clutch issues, fix it now or it'll cost double later. Friction (i.e. the replaceable plates) are cheap, as are the springs, but the plain metal plates are more expensive and will warp as the clutch heats up from slipping.

You don't detail how you are having trouble getting to 2nd gear, but if it's at all clutch related, you don't want to wait. I did for my first clutch job on my 750 seca, where I could feel slippage at 30-40 mph a few hundred miles after I got the bike on the road. I basically let the clutch maintenance slide for too long, and I warped the plain plates.

On my Turbo I replaced the clutch before putting it on the road (as BigFitz52 argues, because a clutch that sits half in oil for a decade or more, the half not in oil dries out and disintegrates on use) Didn't have to replace the plain plates and it's doing great.

The OP really sounds like he's catching the clutch problem early and should be fine after replacement. And he knows when his clutch was replaced last, so I'm assuming it's been ridden more or less continually since then.

 

so far my clutch has done it 2 times.. and only cause I lazily put it in second gear
if I use more force when I put it in 2nd I never have an issue
I am not too worried

 

Different issue. That almost sounds like the 2nd gear dogs slowly whittling down.

Back to the OP, assuming the clutch has been properly adjusted, it's time for new plates and springs. They aren't that expensive, but the peace of mind you buy with it is worth it. Plus proactive maintenance is soooo much better than reactive.

 

It gets ridden pretty regularly and the oil gets changed often...
Time for a clutch pretty soon.

 

Hey guys I know this thread is old but I'm having the same issue at high rpms. So I'm looking around for clutch parts. Seems most vendors are only selling the friction plates. Is it ok to just change those and not the separator plates or springs?

I mean I can find both but we're talking upwards of $170 and that's not including a gasket or springs. Trying to keep it under $100 if possible.

 

The metal plate side reusable but you have to clean them off with the Scotch Brite pad and measure them for Warp. You should always replace the bolts and measure the springs still a good idea just to replace them.

 

https://www.xjbikes.com/forums/threads/clutches-101-part-1-the-400-550-600s-with-pics.29541/

 

Awesome. Great info. Thank you. I'll take a look and see how the plain plates look.

Any idea where to get a gasket? They seem few and far between.

 

Email info@xj4ever.com

 

Is that Len?

 

yes it is.

it is important to replace the clutch bolts the bolts are under a lot of operational stress.
the springs get weak. and dont hold the clutch plates tight.

you should open the cclutch up first to see what you need.
could just need springs and bolts if your lucky and the friction plates are in spec and metal plates just need cleaning and are not warped.

clutch grenading is not a pretty site..
I think polock has a few photos on the site

 

this link
https://www.xjbikes.com/forums/threads/82-650-maxim.119081/page-2#post-598970