Jump to content
Methotic

This is why YOU should do the loctite mods..

Recommended Posts

Was blasting around the trails all day today with some buds. Came back home and noticed an occasional "knock". My first instinct was to pull the stator cover to check them pesky screws on the flywheel and guess what? 2 broken. 

For those who been through this a time or two, what screws should I use? Also is it possible that a bunch of metal shavings got into the crankcase or is it usually all contained by the flywheel? Gonna need a new stator for sure. Here's the aftermath.. 

20191201_184131.jpg

20191201_184713.jpg

  • Like 1
  • Sad 1

Share this post


Link to post
Share on other sites
10 hours ago, Methotic said:

Was blasting around the trails all day today with some buds. Came back home and noticed an occasional "knock". My first instinct was to pull the stator cover to check them pesky screws on the flywheel and guess what? 2 broken. 

For those who been through this a time or two, what screws should I use? Also is it possible that a bunch of metal shavings got into the crankcase or is it usually all contained by the flywheel? Gonna need a new stator for sure. Here's the aftermath.. 

20191201_184131.jpg

20191201_184713.jpg

Loctite wouldn’t have helped you here , screws broke off , maybe too tight. 

 

 

 

 

  • Like 2

Share this post


Link to post
Share on other sites

The question is, does the rotor have to be replaced now? The plastic strips on the inside are toast and there's a few gouges from the bolts rattling around. All damage is contained on the inside of the flywheel. Luckily the other bolts didnt snap off, sparing the gear behind it. 

Share this post


Link to post
Share on other sites

Beyond loctite it is important to understand the grade of bolt used and what the proper torque is. It's been awhile since this was discussed so it's not fresh in my mind but some manuals have a misprint for the torque that will yield the bolts. Note, yield does not mean break while tightening. A bolt is effectively a spring. When you yield it simply means you have stretched it past the point it can return to original form. Doing so effectively reduces the elasticity and clamping effect of the bolt.

Anyway, I believe the offending manuals list the torque at 19 ft-lbs which without going into the full calculation is far too much. Again, off the top of my head if I remember correctly the 10.9 bolt should be around 11 ft-lbs. 12.9 you can go to a couple pounds more.

  • Like 3
  • Helpful 1

Share this post


Link to post
Share on other sites
29 minutes ago, ohiodrz400sm said:

Beyond loctite it is important to understand the grade of bolt used and what the proper torque is. It's been awhile since this was discussed so it's not fresh in my mind but some manuals have a misprint for the torque that will yield the bolts. Note, yield does not mean break while tightening. A bolt is effectively a spring. When you yield it simply means you have stretched it past the point it can return to original form. Doing so effectively reduces the elasticity and clamping effect of the bolt.

Anyway, I believe the offending manuals list the torque at 19 ft-lbs which without going into the full calculation is far too much. Again, off the top of my head if I remember correctly the 10.9 bolt should be around 11 ft-lbs. 12.9 you can go to a couple pounds more.

Thanks for info, from what I know the bolts were not tampered with, but cant confirm since I am the 2nd owner. Do you have any idea what the plastic lining is for on the flywheel? Because it got pretty chewed up. I wonder if there are any companies that made lightweight flywheels anymore. 

Share this post


Link to post
Share on other sites
3 hours ago, Methotic said:

Thanks for info, from what I know the bolts were not tampered with, but cant confirm since I am the 2nd owner. Do you have any idea what the plastic lining is for on the flywheel? Because it got pretty chewed up. I wonder if there are any companies that made lightweight flywheels anymore. 

The plastic lining is there to hold the magnets in place. Give it a clean up and an inspect.  If there are only a couple of gouges I wouldn't get to concerned.  Last time I looked there were no lightweight flywheels available or going to be made.  I have seen someone (on here) turn some weight off the stock flywheel though.

 

You might try:

 

Share this post


Link to post
Share on other sites
17 hours ago, ohiodrz400sm said:

Beyond loctite it is important to understand the grade of bolt used and what the proper torque is. It's been awhile since this was discussed so it's not fresh in my mind but some manuals have a misprint for the torque that will yield the bolts. Note, yield does not mean break while tightening. A bolt is effectively a spring. When you yield it simply means you have stretched it past the point it can return to original form. Doing so effectively reduces the elasticity and clamping effect of the bolt.

Anyway, I believe the offending manuals list the torque at 19 ft-lbs which without going into the full calculation is far too much. Again, off the top of my head if I remember correctly the 10.9 bolt should be around 11 ft-lbs. 12.9 you can go to a couple pounds more.

Make sure you are reading the manufacturers specs correctly. Also, make sure they are in inch pounds, foot pounds or newton meters and adjust the torque wrench accordingly. Easy to mix up specs as some manufacturers give values in all 3 types.

 

  • Like 1

Share this post


Link to post
Share on other sites

I'm thinking the bolts were not tightened. Maybe the last person to installed them put them in finger-tight and just forgot to finish tightening them.

 removed the seat and plastics from my very new EXC-F the other day for cleaning and found that I had put the rubber grommet and screw in the center fuel tank hole but never actually tightened it down. I did notice a little rattle coming from somewhere on my last ride, but luckily this didn't cause any issues,. I am meticulous at maintenance and properly torquing screws. Brain farts are real.

Share this post


Link to post
Share on other sites

 

 

Make sure you are reading the manufacturers specs correctly. Also, make sure they are in inch pounds, foot pounds or newton meters and adjust the torque wrench accordingly. Easy to mix up specs as some manufacturers give values in all 3 types.

 

 

 

 

Good advice. I think that is exactly what happened in the manuals. 19 ft/lbs should of been 19 Nm

 

Share this post


Link to post
Share on other sites
12 minutes ago, ohiodrz400sm said:
5 hours ago, Naaasty said:



Make sure you are reading the manufacturers specs correctly. Also, make sure they are in inch pounds, foot pounds or newton meters and adjust the torque wrench accordingly. Easy to mix up specs as some manufacturers give values in all 3 types.



 

Read more  

Good advice. I think that is exactly what happened in the manuals. 19 ft/lbs should of been 19 KN.

NOT bagging on you at all...but just to show how easy it is for a simple typo 
Pretty sure @ohiodrz400sm meant to type 19 NM or 19 Newton Meters 
kN is Kilonewtons and I am not sure there is a measurement abbreviated as KN??? If there is I dont know it, not finding a reference online for it.

Oh and even 19 NM is too much for even a 6mm fastener in 12.9 grade so I think its overall a OEM typo, not just the unit of measurement. 

  • Like 1

Share this post


Link to post
Share on other sites
NOT bagging on you at all...but just to show how easy it is for a simple typo 
Pretty sure [mention=308689]ohiodrz400sm[/mention] meant to type 19 NM or 19 Newton Meters 
kN is Kilonewtons and I am not sure there is a measurement abbreviated as KN??? If there is I dont know it, not finding a reference online for it.

Oh and even 19 NM is too much for even a 6mm fastener in 12.9 grade so I think its overall a OEM typo, not just the unit of measurement. 
Lol, I need a little teasing sometimes. That's what happens when you post replies whiles ignoring a coworker. After I hit send I realized it. Actually, I butcher a lot of relies my 1st time. I have a bad habit of writing, send, then reading. That's why nearly every post I make has an edit.
  • Like 2

Share this post


Link to post
Share on other sites
3 hours ago, ohiodrz400sm said:

Good advice. I think that is exactly what happened in the manuals. 19 ft/lbs should of been 19 Nm

 

If you tighten in ft/lbs to the Nm value, you will be getting a 25% over-torque.  Just did this on my KTM front caliper bolts... It felt like too much, then I checked the math and found that indeed over-torqued the bolts.  These bolts are rather robust so I was comfortable with backing them off and redoing to the proper specs.  Also very important with torque, all of the values require clean and dry fasteners without oil or grease. Oil or grease will reduce the friction of the fasteners and result in too much torque. 

Share this post


Link to post
Share on other sites

 

 

 

If you tighten in ft/lbs to the Nm value, you will be getting a 25% over-torque.  Just did this on my KTM front caliper bolts... It felt like too much, then I checked the math and found that indeed over-torqued the bolts.  These bolts are rather robust so I was comfortable with backing them off and redoing to the proper specs.  Also very important with torque, all of the values require clean and dry fasteners without oil or grease. Oil or grease will reduce the friction of the fasteners and result in too much torque. 

 

Torque is a calculation to reach a desired clamp load. There are different friction coefficients for lubed or dry threads. How do you know that the factory didn't assume lubed threads when they provided the value? Assuming they are tightening to 70% of yield, what friction coefficient did they assume?

 

Share this post


Link to post
Share on other sites
9 hours ago, rodcrank said:

I'm thinking the bolts were not tightened. Maybe the last person to installed them put them in finger-tight and just forgot to finish tightening them.

 removed the seat and plastics from my very new EXC-F the other day for cleaning and found that I had put the rubber grommet and screw in the center fuel tank hole but never actually tightened it down. I did notice a little rattle coming from somewhere on my last ride, but luckily this didn't cause any issues,. I am meticulous at maintenance and properly torquing screws. Brain farts are real.

I'm sure if they were not tightened they would have failed much sooner. Not to be a jerk, but I ride the DRZ the was it was intended. I put about 30 miles of hard off road riding the day it happened. I stalled out on a few hill climbs which probably did the damage. The bolts looked stressed on the threads for sure. 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...