Clutch and clunk

This has just started recently.

I get a soft delayed quiet ( muffled) "clunk" when starting out in first gear. It happens a second or two after you start rolling and the clutch is fully engaged. Almost like a shaft that gets loaded and then shifts slightly to take up the load.
Sounds wierd and hard to describe.
I have checked the rear wheel on the center stand and it does not appear to have any play in the shaft U joint or final drive, even though it sounds like everything is loading up and there would be slippage along there, as these are the last components to take the load.
Also, my clutch is acting a little wierd, as it is a little harder to get into first from neutral. It grinds more into first than it used to, and even adjusting the cable I cannot get it to disengage completely.
It does not make the bike jump too badly when going into first, as I delay about 5 seconds before engaging first.
Still sounds like a problem.
I am suspecting warped plates etc.
Never have been into the clutch. Do not know the history when the last one was installed, if at all.
No bother, still probably needs a new one.
I don't expect that these 2 issues are related.
Advice and comments are appreciated as always.

 

if you have a book, look up middle gear assembly. that's what makes the clunk most people describe. can you feel it in the seat? kind of feels about like someone gives the back tire a little kick.
it doesn't seem to hurt anything and doesn't do it all the time. sound about right?

 

Thanks Polock,
I took a couple of rides to try to determine the "feel" and I can feel the clunk in my left foot.
This is soft, but present.
It is present almost everytime I take off from a stop.
If this is what you say it is, then I understand this should be no issue?
This may have been happening for some time, but now that I have felt it, I would really like to figure out what it is.
I am sure it was not by design.

 

The middle gear clunk is more-or less by design. There has to be some means of softening the inital take-up of driveline slop without damaging the transmission. many bikes use a cush drive at the rear wheel. Yamaha (and others) chose to utilize a method internal to the transmission. In Yamaha's case they use a sprung cam system in the middle drive gear assembly. This is a metal-on metal shock absorber that will clunk. It is a normal consequence of the design. If the clunk gets worse then there is a precedure for examining the middle drive gear and remedying the issue, but that requires a great deal more effort than simply renewing the rubbers on a cush drive.
You can see the cam system in this photo:

 

Thanks for the info.
So this is what Polock was referring to.
A picture is worth a thousand or so words.
I looked it up in the book also.
So it looks like the spring loads up and as the torque is absorbed it releases and comes back to normal?
So the clunk is a normal part of the process, no clunk when new, but I imagine that as things wear, it would become a little more apparent but still function?
Do I understand this correctly?
I will monitor and if it gets worse I imagine its pull the drive shaft and examine ?
Thanks again guys.

 

Your imaginings are correct. The clunk that signifies excessive wear will be unmistakeable, and it is highly unlikely that you will ever have to deal with that particular issue.

 

Idk what the other three of the big four were doing technology wise but the engineering yamaha used on these engines is impressive for the era. I'm not skeptical anymore of original owner members that say they've been wrenching on and riding the same bike for 30 years.

Gary H.

 

Thanks k-moe.
I appreciate the response.
So not to worry about the noise and just appreciate the unique characteristics of the bike.
As I ride her more, and work on her , (having only owned it for a year), I get to discover her distinct signature.
I guess it takes time to understand what is normal and what will need attention on this 32 year old.
Seems to parallel another girl in my life......after 24 years I still am discovering her distinct signature.
Everyone's help is greatly appreciated.

 

Actually, Yamaha used the cushioning method too, on some models..............XJ550's, XJ650 Turbo, XJ700-X, XJ750-X, and XJ900 models use rear wheel hub "dampers" (similar to what is used inside the starter clutch units)........it's understandable on the chain-drive XJ550 models, but I guess on the "high-performance" models Yamaha felt it necessary to use the dampers ALONG WITH the middle gear damper system to tame the torque from enthusiastic operators and such.

 

I did not know that. See how you really do know more than I do

I wonder (given that the other shafties are later models) if Yamaha added the cush drives to alieviate complaints about the middle drive gear "clunk".

 

Wow, I am always amazed with the amount of detailed info there is about these bikes.
Just when you think that you have heard all there is to know about a particular item, someone comes up with even more.
Amazing forum.
Amazing people with the desire to share their knowledge.
Without you all, there would be a lot more struggles to fix and maintain my girl.
Thanks to all

 

Perhaps, but most of the Yamaha models of that era are built to overkill standards, yes they made some mistakes (starter clutch and primary chain guide), but other than that they're quite the heavy-duty little beasts (especially considering their level of performance). They started using the wheel hub cushions in 1982 on the Turbo model, and then again on the "big boy" XJ900 (1983) and then the XJ700-X models (1985-86). Note that they did NOT use them on the XJ700 airheads, even though it too was a brand new model. So I think that engineering analysis told them that it just wasn't really needed on the lower-torque engines, clunk noise or not.

I tend to think of Yamaha in a similar vein as the Dodge-Plymouth-Chrysler company of old; great and innovative engineering, but maybe not that much concern with aesthetics, I'm not saying that they aren't good looking bikes, but they are somewhat "basic" in a lot of areas, because a complaint like "it clunks a bit in 1st gear" goes to a panel of marketing geeks, and they go running to engineering and corporate and say "we've gotta fix this before word gets out of this clunk, it will cost us sales!" whereas if the complaint goes to an engineering-focused company, they sit around and say "yeah, so what? Did anything break? If not, no problem, now leave us along while we finalize this 5-valve engine design.....".

 

I think that you're correct about that. And from a production cost standpoint the addition of a rear wheel cush drive makes a lot of sense considering how much larger the middle gear damper would need to be to deal with the additional torque.