Rear brake clunk on hard sudden braking (2017 Yamaha FZ07 ABS)

[SEANDROID]

Hello everyone,

 

Thanks in advance for taking the time to reply to my post below.

 

Earlier today I decided to tighten, clean and lube my chain. I followed the instructions in the owner's manual - but I ended up loosening the rear axle nut way too much (could spin it freely with one finger). 

 

As a result, I totally lost alignment on the rear wheel - to a point where there was a bit of play when i shook it - but managed to get it all back together and aligned both sides equally using the scale stamped on either swingarm.

 

I even measured with a tape from the center of the swingarm pivot to the center of the axle nut on both sides and it was equal. 

 

I was still paranoid about the alignment so i went for a small test ride round the neighborhood and the bike didn't swerve or vibrate under normal progressive braking. 

 

It was when I braked really hard and suddenly with the rear brake, that I heard a distinct "clunk". Almost the same as when you engage first gear.

 

This clunk would kick in and out until the bike had stopped completely and was accompanied by a whirring noise (similar to that of the fuel pump priming when you start the bike).

 

This clunk would not happen while the bike is in the process of stopping but happened just about when the bike was going to stop and the wheel was going to lock. 

 

It is not something I have noticed before. Although I have never jumped hard on the rear brake before today - so by means of my paranoia I associate it with the misalignment mistake I made.

 

It does not happen under progressive braking. 

 

Is this the ABS? Should I be worried? Below is the link to a video I took of this noise while the bike was on the rear paddock stand. Please have a look and let me know. You might need headfones to hear it distinctly. 

 

https://youtu.be/ahJdfrGlrZM

[shinyribs]

I don't see anything out of the ordinary there. 

 

These rear calipers are not like automotive calipers, or our front calipers, where they are rigidly mounted. They float on the rear axle and there is an anchor slot they engage in to on the swingarm to keep them stationary. That slot is a snug fit, but not extremely tight. It's normal for a caliper to click like that when suddenly clamping on the brake like that.  They also float on pins that , again, do have a tiny degree of slop in them. That slack has to go somewhere. BUT...your caliper should be fairly tightly clamped in to place when the rear axle is tightened,so the caliper should not really be slopping back and forth easily. I watched your video several times and I couldn't see the caliper or it's mount moving around excessively. Regardless, I would make sure your axle is fully tightened.

 

But the whirring you describe sound exactly like the ABS system being triggered. However, you should be able to easily feel that in the brake pedal. I know I activated the ABS on the 07 I test rode and I could feel the pedal vibrating/pulsing as the ABS system modulated the pressure. 

[SEANDROID]

5 hours ago, shinyribs said:

I don't see anything out of the ordinary there. 

 

These rear calipers are not like automotive calipers, or our front calipers, where they are rigidly mounted. They float on the rear axle and there is an anchor slot they engage in to on the swingarm to keep them stationary. That slot is a snug fit, but not extremely tight. It's normal for a caliper to click like that when suddenly clamping on the brake like that.  They also float on pins that , again, do have a tiny degree of slop in them. That slack has to go somewhere. BUT...your caliper should be fairly tightly clamped in to place when the rear axle is tightened,so the caliper should not really be slopping back and forth easily. I watched your video several times and I couldn't see the caliper or it's mount moving around excessively. Regardless, I would make sure your axle is fully tightened.

 

But the whirring you describe sound exactly like the ABS system being triggered. However, you should be able to easily feel that in the brake pedal. I know I activated the ABS on the 07 I test rode and I could feel the pedal vibrating/pulsing as the ABS system modulated the pressure. 

@shinyribs

 

Thank you so very much for taking the time to look into this.

 

I made sure that the axle was tightened to 76 ft lbs as mentioned in the owner's manual.

 

And to your second point, I could distincly feel it in the pedal. Vibrations, pulses, engagement, disengagement. All of it.

 

For future reference, how many turns is good enough for the axle nut to be loose so that I can still adjust the chain tension without causing such a mess?

 

Also, any particular wheel alignment tool you would recommend?

[shinyribs]

It's really hard to say how many turns would put the axle tension in a good spot for maintenance. It's more something that you have to feel. But the adjusters will be effective even when the axle nut is still pretty tight, even tighter than hand-tight.

 

I don't have any certain tool for wheel alignment, I just use strings when the need arises. It'd be very difficult to explain the process of using string via text, but I'm sure you could find some videos about online. MotionPro makes a chain alignment tool that is inexpensive. I think it's less that $20. I've never used one, but MP seems to always make good stuff and it looks like a pretty effective way of making sure the rear wheel is straight in the chassis. It seems to me that the alignment rod is way too short, but maybe it's fine. Or maybe you could supply your own longer rod. 

 

 

There are also laser alignment tools out there. I haven't looked in to them, but lasers are pretty cheap nowadays. 

 

 

[SEANDROID]

55 minutes ago, shinyribs said:

It's really hard to say how many turns would put the axle tension in a good spot for maintenance. It's more something that you have to feel. But the adjusters will be effective even when the axle nut is still pretty tight, even tighter than hand-tight.

 

I don't have any certain tool for wheel alignment, I just use strings when the need arises. It'd be very difficult to explain the process of using string via text, but I'm sure you could find some videos about online. MotionPro makes a chain alignment tool that is inexpensive. I think it's less that $20. I've never used one, but MP seems to always make good stuff and it looks like a pretty effective way of making sure the rear wheel is straight in the chassis. It seems to me that the alignment rod is way too short, but maybe it's fine. Or maybe you could supply your own longer rod. 

 

 

There are also laser alignment tools out there. I haven't looked in to them, but lasers are pretty cheap nowadays. 

 

 

Understood. However today I tested another theory. I ran the bike, picked up some speed, pulled the clutch, turned the key off so all power to the electricals is cut and then braked hard on the rear. Heard the clunk once and the wheel locked. Something is definitely misaligned I'm afraid. Trying to deduce what it could be. 

[fzar]

This is what I found today!’ I’m pissed

[DewMan]

5 minutes ago, fzar said:

This is what I found today!’ I’m pissed

That's scary.

 

is the adjuster bolt busted or is the axle not tight?

[fzar]

To explain what is going on in that photo. I was checking the chain slack, it was within the 51-56 mm, I noticed that the tyre wear indicators were wearing un-evenly from 1 side to the other. I assumed there was a mis-alignment with the rear wheel or the front, I started with the rear. I used what I had on hand a straight-edge (steel ruler) and the sprocket just below the teeth right up under the chain and sighted it through the c/s!! all good. Puzzled I got up off my knees and stumbled a little, grabbed the back wheel and this happened to my disbelief I shouted wtf. got my torque wrench, checked to see if it was the specified 76 ft/lbs, it clicked at 76 ft/lbs. The last person to touch my rear wheel and axle was a local dealership that mounted a set of tyres before I had my rear stand.

I just brought the tyres the day before and brought the bike the next day. (5 months ago)

I decided that I'm going to find out wtf is going on here,( its un-rideable) sprayed the exposed thread on the axle with kerosene, fine hair paint brush to get out anything that might obstruct the removal of the axle nut. Grabbed my wrench and 27 mm socket, I get the axle nut off but it wasn't as easy as you would think. I remove the caliper, wheel, chain etc. I inspect the nut and the axle, low and behold its cross-threaded to f##k. I'm pissed, so for the last 5 months/ 5k miles the axle was loose and I trusted the dealership and I didn't check their work. # Impact driver stealership.

I'll be heading their way tomorrow to see if we can resolve this issue. It'll cost me around $50 without shipping cost for a new axle and nut from partzilla, if the dealership doesn't admit responsibility or lack of responsibility of notification if it was a problem before they touched it. I want it to be know that if I get nothing from this (which I expect) I'd like it to brought to their attention the danger they put me in, and they have a responsibility to their fellow riders that this is not acceptable.

Rant over.

 

P.S : I rode '18 MT-10,MT-09, R6, this weekend at bike,blues and barbeque. Demo-ride but it was a RIP, serious RIP the lead rider wasn't messing around. I also rode H-D 1200 roadster,750 street-rod, FXDR 114-ci, and some. H-D were generous with their lack of supervision and unlimited rides, versys Yamaha's 2 rides PP, P-Day. I found out I'll never have a wet-dream about a H-D, EVER! 

[fzar]

38 minutes ago, DewMan said:

That's scary.

 

is the adjuster bolt busted or is the axle not tight?

     @DewMan,I posted an explanation,I'm pissed.

 

[DewMan]

10 minutes ago, fzar said:

     @DewMan,I posted an explanation,I'm pissed.

 

As I would think you have every right to be... they owe you new parts... but not to install them.. since they obviously can't be trusted.

[fzar]

This is the axle. Sorry the pics and video are to big to show all at once, the video I took really show the extremity of the issue but I don't know how to edit to make it compatible size wise for it to post.

 

[fzar]

If I'm making any sense right now (being pissed off) my take of what went wrong is that whoever did this got the 76 ft/lbs reading by click or by beep and called it a day. I was talking to the regional Yamaha parts supplier at BB+BBQ for an extended time thursday and friday and I brought up the issue of this guy at  treating me like a fool.

I was sure to let him know that I'll never do business with them again, no shet, that conversation happened.The feckin irony is ironic!!!!!! I even saw the tent and I was looking for a rep to chat with (freedompowersports) that is, I was in the mindset I wasn't  being fair by judging a experience I had with 1 guy to tar them all with the same truck. Yes TRUCK.

 

  Anyway all I can say is I'll be following up with these guys and I'll report back. Do you own due diligence people, if any of you knew me you'd know how mad I am at myself right now. Yeah ya live and learn, or maybe not in this case. I got lucky I found this.

[fzar]

Here’s the axle nut!!!

[shinyribs]

I'm not trying to side against you, fzar. It's easy to see that what happened was in fact a mechanics error. However, I don't think the axle and nut were actually cross-threaded. That damage doesn't matchup. But those threads are definitely galled! So like you said, the threads were tight and the mechanics torque wrench clicked even though the axle was actually still loose. That is,if he even used a torque wrench. 

 

These Fuji nuts on these axle are famous for galling threads like this IF they are run dry. That's most likely what happened. When you get a replacement be sure to get some anit-sieze on there and you'll be golden. The locking teeth of a Fuji nut are plenty strong to still lock the nut to the axle even with the anit-sieze being present. 

[fzar]

1 hour ago, shinyribs said:

I'm not trying to side against you, fzar. It's easy to see that what happened was in fact a mechanics error. However, I don't think the axle and nut were actually cross-threaded. That damage doesn't matchup. But those threads are definitely galled! So like you said, the threads were tight and the mechanics torque wrench clicked even though the axle was actually still loose. That is,if he even used a torque wrench. 

 

These Fuji nuts on these axle are famous for galling threads like this IF they are run dry. That's most likely what happened. When you get a replacement be sure to get some anit-sieze on there and you'll be golden. The locking teeth of a Fuji nut are plenty strong to still lock the nut to the axle even with the anit-sieze being present. 

I wouldn't think you or anyone is siding against me, yeah its an error on their part like I said maybe it existed before they touched it! I bought the bike with 2,100 miles on it, with all the paperwork for first service etc. But they have a responsibility to let me know and show me the problem if it wasn't their fault. Crossed threaded and all that i was not in the mood to diagnose any further that I didn't do this, and with all I do to be as safe as can be I missed this 1, but they have to have some burden too. I'm just pissed that I could be dead due to somebody lacking attention. I'm aware the nut is an issue, but so should they! Anyway if you look at the axle thread  you'll see something went bad just at about hand tight, from that point it was deemed suffice. I'm just going to talk to them, I dropped the hatchet and put it down to lesson learned!

 

 

[fzar]

I spoke with the dealership yesterday, brought the axle,nut, and video with me and showed them. they inspected it and said the tech that did it is usually very attentive to these things! Their willing to replace both axle and nut. To be honest the GM wasn't admitting guilt, but said they stand over their work so a replacement will be got. How long it will take? I don't know, I'll call tomorrow.

To the OP, sorry for hijacking your thread.

[sorkyah]

2 hours ago, fzar said:

I spoke with the dealership yesterday, brought the axle,nut, and video with me and showed them. they inspected it and said the tech that did it is usually very attentive to these things! Their willing to replace both axle and nut. To be honest the GM wasn't admitting guilt, but said they stand over their work so a replacement will be got. How long it will take? I don't know, I'll call tomorrow.

To the OP, sorry for hijacking your thread.

"the tech is usually very attentive" is the standard line they're taught. 
i was given the exact same line twice when they stripped out my seat bolts, and when they over-tightened the chain on my bike(slack ended up at .5")

[rick]

Yep, looks like the new t was tight, but cause the threads were galled. 

 

U can't really know what the torque applied was. As static friction will try to hold things still, the nut could still have been looser than it should have been. Think about how much more force it takes to get a piece of furniture moving vs. after its moving. 

 

Next  time you loosen that nut, put some penetrating fluid on the threads 1st. 

 

Will the the dealer let you do the work and then reimburse you for the price of the parts?

[fzar]

1 hour ago, rick said:

U can't really know what the torque applied was.

No idea what they had it at. I checked to see if it was at 76 ft/lbs before I did anything else, and it was, but as you said it was at 76ft/lbs to that point because of galling.

 

1 hour ago, rick said:

Next  time you loosen that nut, put some penetrating fluid on the threads 1st. 

As in my original post I didn't use penetrating fluid. I used kerosene and a fine hair brush before I disassembled so it didn't get permanently stuck, to where I'd have to start drilling or what not. I was pissed, tbh I should have taken a step back and relaxed before I got into it!

 

1 hour ago, rick said:

Will the the dealer let you do the work and then reimburse you for the price of the parts?

My agreement with them as of now is they are ordering the parts at their cost. The bike is unrideable, I have the OE damaged axle and nut in my possession. Their going to call me when it comes in and we'll exchange damaged for new. I'm reinstalling it whether they like it or not, they didn't discuss it with me, either way I can't get the bike to them without a rear axle and nut.

 

 

Thanks for your insight. @rick

[fzar]

1 hour ago, sorkyah said:

i was given the exact same line twice when they stripped out my seat bolts, and when they over-tightened the chain on my bike(slack ended up at .5")

Holy macadamia nuts, what the hell was being smoked that day???

[rick]

Guess we've now seen a couple of these axle nuts gall into the threads - likely as they were being loosened. Think they are actually suppose to be replaced each time. We've seen a couple of totally mangled side plates (right side) where it took so much force to unscrew the nut that the flange where the axle flats sit was destroyed. 

 

My point about checking the torque applies to any static fastener - with or without damaged threads. If you were to tighten that nut to, say 65 ft-lbs, stop, reset the wrench to 75,  you might find that the wrench will release and click w/o the nut moving. That, of course, doesn't mean it's at 75 ft-lbs. The static friction on the any fastener is holding it in place and adds force needed to move it. 

 

Not sure that kerosene is much of a lubricant. Lots of people swear by a home brew that's a 1:1 mix of ATF:kerosene. Substituting fork oil might give the same results.

 

Keep in mind, when it comes to tightening, lubrication on the threads and face on the nut will decrease friction and result in a tighter fastener that if it was installed dry. 

 

 

[DewMan]

1 hour ago, rick said:

Guess we've now seen a couple of these axle nuts gall into the threads - likely as they were being loosened. Think they are actually suppose to be replaced each time. We've seen a couple of totally mangled side plates (right side) where it took so much force to unscrew the nut that the flange where the axle flats sit was destroyed.  

 

My point about checking the torque applies to any static fastener - with or without damaged threads. If you were to tighten that nut to, say 65 ft-lbs, stop, reset the wrench to 75,  you might find that the wrench will release and click w/o the nut moving. That, of course, doesn't mean it's at 75 ft-lbs. The static friction on the any fastener is holding it in place and adds force needed to move it.  

 

Not sure that kerosene is much of a lubricant. Lots of people swear by a home brew that's a 1:1 mix of ATF:kerosene. Substituting fork oil might give the same results. 

 

Keep in mind, when it comes to tightening, lubrication on the threads and face on the nut will decrease friction and result in a tighter fastener that if it was installed dry.  

 

 

All this talk of the propensity of galling on the rear axle/nut has me paranoid. I'd prefer to minimize the chances of galling by replacing either the nut and or axle as a preventative measure. Would replacing the OEM nut with an aftermarket Gilles titanium nut be enough to minimze the likelihood of galling?

I miss the good old days of using a cotter key to lock the axle nut without any over engineered locking mechanisms.

[norcal616]

axle nut is supposed to be one time use... 45-50ft/lb and a dab of blue loctie, served me well over the years till I own a single side swingarm... 

[DewMan]

13 minutes ago, norcal616 said:

axle nut is supposed to be one time use... 45-50ft/lb and a dab of blue loctie, served me well over the years till I own a single side swingarm... 

Replacing the axle nut every time I adjust my chain seems unreasonable. The shop manual does not suggest replacing the axle nut when doing tire replacements nor chain adjustment.
 

[norcal616]

3 minutes ago, DewMan said:

Replacing the axle nut every time I adjust my chain seems unreasonable. The shop manual does not suggest replacing the axle nut when doing tire replacements nor chain adjustment.
 

i agree, I barely crack the nut loose to any adjustment... but for tire changes, yea I put a new nut on... that stupid metal tab on the nut face that follows the threads is the main reason I replace the nut...