Guidance for Troubleshooting Clutch

[chunkygoat]

Hi everybody, I come to the forums today asking for help or guidance in troubleshooting my 2008 FZ6 S2. I bought this bike brand new of the showroom floor and have since put ~45,000 miles on it. I don't ride too aggressively, however I do have a tendency of doing some clutch up wheelies out of first on back roads when there isn't a soul in sight. :spank: Anyway, sorry in advance for the 20 questions, any help is appreciated.

With that said, today, while riding not aggressively -- a few miles into my ride in about 4th gear @ 45mph, something "gave" with no audible sound. The RPMS climbed to around ~7000 and the bike started to coast, in gear. I pulled the throttle back slightly, RPM's climbed to ~9,000 -- bike was still coasting. I coasted to the side of the road and shifted down to first, and when i released the clutch, the bike would not move forward. I turned around and pushed it, uphill, all the way home. Whew! :rockon:

After trying a few different things, I've noticed:

• I can still shift into any gear
• Pulling the clutch in and releasing it has no impact on the bike.
• Bike stays stopped with engine running, and in gear.
• The bike will not transfer power to the wheel, in any gear.
• No error codes
• No strange noises

My shotgun reaction is that the clutch gave way. Before I start disassembling and looking more closely, I wanted to get a post out there to see what kind of response I may get. I'm not extremely mechanically inclined, more electrically. After this post I plan on draining the oil first and looking for any debris or shavings that may or may not reveal some important evidence of something other than the clutch, just in case. I've done some searching here on the forums for "clutch" and "clutch replacement" and was able to find somebody who mentioned that their clutch felt stuck engaged. He describes slightly similar symptoms, but not exactly. Beyond draining the oil and searching for shavings, my only thought is to examine the clutch cable, but I am not sure what I would be looking for that may confirm that the cable is the issue.

-Does anybody have any suggestions for where to start troubleshooting beyond draining the oil and examining the clutch cable?-
-Do the symptoms I describe sound like they align with a damaged clutch cable?
-How long does a typical clutch last? I've read after googling many people getting at least 45,000 miles on a clutch.
-What indicators should I look for when examining the clutch cable?
-Are there any good clutch replacement how-to's that anybody can suggest?
-Any other good resources to learn about this part/system? Diagrams, websites, etc. (aside from the service manual).
-Any other thoughts or suggestions?


Any suggestions you guys have or help or guidance you can provide is greatly appreciated.

 

[FinalImpact]

If your lever at the clutch cover is aligned, there is dot on the lever and a triangle on the case, that implies the lever moving the clutch is in the home position and the clutch is engaged. Your engine should be locked to the transmission. If the lever dots do not align, your cable could have frayed and stuck in the housing.

Basically loosen the tension at the thumbscrew on the lever (screw it in towards the lever). If this does not help the case marks align, the cable maybe holding the clutch disengaged.

BUT - you say you were steady state, not shifting and the RPMs soared. This doesn't add up. Cable failure would have occured during clutch usage/disengaging, not steady state clutch NOT being activated.

Look for a peen mark on the lever and trangle on the case. If they align and your trans is not connected to the engine, it sounds like the clutch blew up.

Drain the oil but there is no guarantee you find bits until you pull the pan. So, id pull the clutch cover before the pan. If it blew up, you will be pulling the pan...

Also, with thumb scew loose up top, you should be able to pull the cable at the case by hand unless its stuck in the housing.

 

[TownsendsFJR1300]

Check and see if your front sprocket is still attached to the output shaft as well as the condition of the sprocket.

Also, how does the clutch "pull" feel, normal?

 

[chunkygoat]

Thanks for the reply guys! I can always count on you two to give some solid advice.

If your lever at the clutch cover is aligned, there is dot on the lever and a triangle on the case, that implies the lever moving the clutch is in the home position and the clutch is engaged. Your engine should be locked to the transmission. If the lever dots do not align, your cable could have frayed and stuck in the housing.

Basically loosen the tension at the thumbscrew on the lever (screw it in towards the lever). If this does not help the case marks align, the cable maybe holding the clutch disengaged.

BUT - you say you were steady state, not shifting and the RPMs soared. This doesn't add up. Cable failure would have occured during clutch usage/disengaging, not steady state clutch NOT being activated.

Look for a peen mark on the lever and trangle on the case. If they align and your trans is not connected to the engine, it sounds like the clutch blew up.

Drain the oil but there is no guarantee you find bits until you pull the pan. So, id pull the clutch cover before the pan. If it blew up, you will be pulling the pan...

Also, with thumb scew loose up top, you should be able to pull the cable at the case by hand unless its stuck in the housing.

After inspecting the clutch cable both at the hand lever and at the lever at the case, everything appears ok. Pulling the clutch in pulls the cable and engages the lever at the case as I would expect and everything appears to be aligned. See below for what I found.

Check and see if your front sprocket is still attached to the output shaft as well as the condition of the sprocket.

Also, how does the clutch "pull" feel, normal?

Nailed it here Townsends, again. When I pull the clutch in, it feels completely normal. I did take the drive sprocket cover off and noticed something moderately embarrassing and and completely obvious


Notice the drive sprocket nut and lock washer are mysteriously missing. The threads appear to be damaged too, although not severely -- I'm not sure I trust them anymore.


The drive shaft was spinning freely inside of the front sprocket.


The two parts in red are completely gone. It remains mysterious to me how the nut could have worked its way off, with me not hearing, feeling, or noticing this. Perplexing, I always use a torque wrench.


I can easily buy a new drive sprocket nut ($9.73) and drive sprocket lock washer ($4.22) from Bike Bandit, but do you think the drive shaft needs to be re-threaded or replaced? Looks like a small chip came off the threads.

Anyway, thanks for your help guys, I greatly appreciate it!

 

[TownsendsFJR1300]

Figured that was it.

I know you torqued the nut BUT, did you flatten the nut over the TWO flats on the output shaft?

That IS the "actual locking part" of the nut. If so, torque alone wasn't enough and vibs loosened it (obviously)..


Re the output shaft. To change that is a MAJOR FULL engine tear down.

If you could post the best close up picture you can would be good.

Now, the splines are taking the brunt of the torque. Although the shaft is hardened, it can't hurt to get a metric
thread file and try to clean it up.

*** Looking again at your pic's close up, the threads don't look too bad, luckily.
if the new nut starts and threads without issue, your good

Super clean the theads / nut, red loctite plus the proper NUT, torqued and penned over.

**BTW, a small chip in the shaft, outboard, shouldn't be an issue, getting a new nut started and torqued IS CRITICAL.
Torqued properly as in "not stripping the nut as its forced on", thread to thread..

If not, some backyardian options to follow so you don't have to take the engine apart..


BTW, parts are a little cheaper here:
Yamaha Motorcycle Parts 2008 FZ6 - FZS6XCL TRANSMISSION Diagram

 

[chunkygoat]

Figured that was it.

I know you torqued the nut BUT, did you flatten the nut over the TWO flats on the output shaft?

That IS the "actual locking part" of the nut. If so, torque alone wasn't enough and vibs loosened it (obviously)..


Re the output shaft. To change that is a MAJOR FULL engine tear down.

If you could post the best close up picture you can would be good.

Now, the splines are taking the brunt of the torque. Although the shaft is hardened, it can't hurt to get a metric
thread file and try to clean it up.

*** Looking again at your pic's close up, the threads don't look too bad, luckily.
if the new nut starts and threads without issue, your good

Super clean the theads / nut, red loctite plus the proper NUT, torqued and penned over.

**BTW, a small chip in the shaft, outboard, shouldn't be an issue, getting a new nut started and torqued IS CRITICAL.
Torqued properly as in "not stripping the nut as its forced on", thread to thread..

If not, some backyardian options to follow so you don't have to take the engine apart..


BTW, parts are a little cheaper here:
Yamaha Motorcycle Parts 2008 FZ6 - FZS6XCL TRANSMISSION Diagram

Thanks again Townsends -- you're the man. Is there anything you don't know?? :thumbup:

Anyway, the threads look great after cleaning them up. I noticed, as you said, the drive shaft is notched, which I was not aware of. I bought the replacement nut and washer, one thing I am not clear on is when you say the nut should be "penned over" -- what does this mean?

It looks like once tightened, you "flatten the nut over the two slots". Do you mean you literally mallet the nut so it flattens over the two slots? Is this what you mean penned?







Anyway, thanks a bunch for your help. Should have this squared away this week. Just looking for clarity on what the two slots are and what "penned over" and "flatten the nut over the two flats" means.

Thanks again!:rockon:

 

[TownsendsFJR1300]

Your very welcome!

Anywho,

The new nut should have little bit of a thin lip on it facing outward.

Torque down the sprocket, washer, nut (loctite if you want) to spec's.

**Now, where those two flats are, smack down the thin part of the nut into that flat on both sides.**

That acts as the lock-nut, Don't go crazy hammering it, (its supported with bearings you don't want to destroy)
but it should be visibly indented...

Your clean up looks real good BTW, got lucky there!!!

Note: Might be one flat there, I forgot, its been awhile since I changed mine out.

 

[chunkygoat]

Ah, makes perfect sense. And yeah, definitely feel like a dodged a bullet on this one. The whole situation could've unfolded completely different, I'm ok -- the bikes ok -- so I'm happy. I also spent a lot of time cleaning and degreasing everything "not visible" in the down time so I'm pumped that it all worked out.

Thanks again dude!

 

[TownsendsFJR1300]

Ah, makes perfect sense. And yeah, definitely feel like a dodged a bullet on this one. The whole situation could've unfolded completely different, I'm ok -- the bikes ok -- so I'm happy. I also spent a lot of time cleaning and degreasing everything "not visible" in the down time so I'm pumped that it all worked out.

Thanks again dude!

No problem, nice easy fix!

 

[stefangeir]

Just changed my front sprocket, and was surprised to see that there was no lock washer as shown in the manual. Searched this forum for "Front sprocket lock washer" and found this thread which is the perfect explanation. There is no lock washer!

I had no idea I should bend the nut into the flats of the thread. I basically had the exact same reaction as chunkeygoat did here:
1) I thought my lock washer was missing
2) I thought my thread was destroyed because of those two dents.

But there is no lock washer and those two dents are what you use to lock the nut! Perfect. I'll go and hammer the nut to lock it later today.

This forum is the perfect encyclopedia for this bike. Just for fun, here's a picture of old and new sprocket:

 

[FinalImpact]

After the nut is tight 61ft/lbs (85nM)....
An option I use instead of the hammer and punch is vice grips to crush the nuts rim into the ground keyway.
It goes like this: using two round punches of small diameter hold them over the output shaft keyway slots. Adjust visegrips and clamp the nut crushing the rim into keyway.

Drive axles on FWD cars often use the same style of lock nut and this has worked well there. On the bike you can do one side at a time too.
The method eliminates bearing shock and reduces risk of other problems....

Was your sprocket swapped before this happened? Did the OEM install fail and allow the nut to free itself?
Just curious. Thanks

 

[TownsendsFJR1300]

Just changed my front sprocket, and was surprised to see that there was no lock washer as shown in the manual. Searched this forum for "Front sprocket lock washer" and found this thread which is the perfect explanation. There is no lock washer!

I had no idea I should bend the nut into the flats of the thread. I basically had the exact same reaction as chunkeygoat did here:
1) I thought my lock washer was missing
2) I thought my thread was destroyed because of those two dents.

But there is no lock washer and those two dents are what you use to lock the nut! Perfect. I'll go and hammer the nut to lock it later today.

This forum is the perfect encyclopedia for this bike. Just for fun, here's a picture of old and new sprocket:

It'll be a little quieter up front as well.. You got your moneys worth out of that sprocket!

 

[chunkygoat]

After the nut is tight 61ft/lbs (85nM)....
An option I use instead of the hammer and punch is vice grips to crush the nuts rim into the ground keyway.
It goes like this: using two round punches of small diameter hold them over the output shaft keyway slots. Adjust visegrips and clamp the nut crushing the rim into keyway.

Drive axles on FWD cars often use the same style of lock nut and this has worked well there. On the bike you can do one side at a time too.
The method eliminates bearing shock and reduces risk of other problems....

Was your sprocket swapped before this happened? Did the OEM install fail and allow the nut to free itself?
Just curious. Thanks

Hey Final, late reply. This was after I did the 520 16/47T conversion. It was 100% my failure to lock the nut.

P.S. thanks for the vice grip tip!