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Has anyone else had a problem with torqueing the 6 Allen bolts that hold each of the front rotors on the hub? If yes, has anyone approached Honda?

Sorry for the length of details, just want to be through and make sure no one is injured.

Thru various attempts and two tests, I've broken six out of the 12 bolts between the two rotors. Spoken to three Honda dealerships (Ontario, Canada) and a long time AT rider. Everyone is shocked and never heard of this before. When I ordered more bolts from my Dealer, Honda Canada only had eight bolts left in the warehouse. I asked why so little, he mused that nobody needs them. He's never had to order before. (I mused silently the reason is that we Canadians go thru so many!)

From my research these bolts I suspect are on many models of Honda bikes. So why are my bolts snapping like frozen butter? If this can help someone in the future, hopefully this will fast track your "adventure" and you'll get thru this faster than I have. Haven't been able to use bike for three weeks!! So far! Still not running.

Sequence of events:
  • first four bolts snapped while working in garage at temperatures ranging from +5C to -3C
  • after first two of those four, took brand new torque wrench back to Princess Auto for replacement. They checked wrench and said it was fine. I either set the wrench wrong or there is something wrong with bolts
  • carefully proceeded and the next two snapped
  • theory was too cold in garage, put all tools, parts and wheel in house at 20C for a week
  • note, Red Locktite used in all attempts
  • ordered more bolts from Honda at $4.91 CAD (approx. $3.89 USD) EACH after trying to find at more reasonable price elsewhere
  • still waiting to pu bolts from Honda dealership, ordered a package of 20 bolts from US for $1 USD each
  • in prep for new bolts coming thought I'd take the remaining bolts I have and put in three per rotor so I'd have at least those in while waiting for new ones
  • of those six bolts two torqued okay, four would not.
  • of those four that would not I broke two of them while trying
  • I even started at 10 ftlbs instead of the required 15 ftlb. Ten was okay, 11 okay, 12 okay, then broke at 13 ftlbs!! picture below of wrench setting


Font Gas Publication Cylinder Metal Thermometer Temperature Font Material property Gas

Possible causes:

  • substandard bolts got onto my bike somehow
  • too cold in garage making stainless steel too brittle, but same happened in 20C house
  • too much Locktite in hole preventing bolt from continuing to bottom, however each broken bolt did appear to make it to the bottom

Next steps:
  • install brand new Honda bolts - part# 90106-MMB-000 with remaining bolts I have.
  • during this install I will torque "sequence" each bolt starting at 10 ftlbs, then 11, then 12 and so on up until breaking or 15 ftlbs which ever comes first
  • I will reach out to buddies with small torque wrenches and compare my 15 ftlbs to their wrenches
  • depending how the above goes, I might replace all or some of the 12 bolts I've ordered here:


Ask of fellow AT Forum friends:
  • has anyone else experienced this? Heard of this? If yes, please post on here so that I can reach out.
  • purpose #1 is to see if I am "special" or if this is common
  • purpose #2 to prevent anyone from failing bolts causing crash and injury
  • purpose #3 prevent any fellow AT or other model Honda owners from wasting weeks of their life tracking down this bull ****
 

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Out of curiosity, did Princess Auto just send you back home with the same torque wrench? If so, what did they actually do to check the calibration of that wrench? Hopefully, they actually used a calibration tester?

I have not heard of any of these bolts breaking on the Africa Twins, particularly to the alarming degree yours are breaking. It is possible it could be a bad run, but you would think one or two breaking, not only 1 or 2 surviving.
 

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The problem is you shop at Princess Auto. You need to go to Prince Auto because the AT is a manly machine....just kidding. I agree with Cuchulainn regarding the torque wrench. Most part stores in my area don't have a torque wrench calibration tool and if they did, they probably wouldn't know how to use it. The good ones can be very expensive. I am friends with our local junior college automotive professor and he lets me use the school's calibration tool to check my wrenches ( I bit the bullet and bought a quality 1/4, 3/8 and 1/2" drive set.) Maybe an option for you if you have a school close by or one of those automotive tech schools in your area. I can't tell what brand you are using but it is worth spending good money on a torque wrench since it is a precision tool. My friends who use Harbor Freight torque wrenches (or China Freight as it is more commonly referred to) are constantly breaking small hardware off and probably stretching the larger bolts as well. Let us know what you find out.
 

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I suspect your torque wrench.

Nominal Torque wrench accuracy is +/- 4% (check your specific version). This is as a % of full scale, so in your case 4% of 80 ft-lb or +/- 3 ft-lb. Better to use a torque wrench in the middle of rating not the bottom end.

Temperature won't make any difference to the materials in the range you are able to work on your bike.

I wouldn't torque sequence 10,11,12,13 ... sliding vs static friction ... I'd go hand wrench snug first, then 10 in a star pattern followed by 15 in a star pattern

Don't use red loctite on the Honda disk bolts - they are ALOC - the thread locker is already on the bolts. If you do reuse the bolts use blue loctite. Else you will need a heat gun or torch to soften the red lactate for removal.

Sounds like it's time to start over. Chase the holes with a tap to remove remnants of thread locker. Don't re-use any bolt you have already torqued with the suspect wrench.
 

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I see the stated torque value for those bolts in the manual is indeed 15 ft-lbs, but that's twice as high as the "normal" value for 6mm Honda bolts. Any chance the manual has the wrong values? Has happened before.
 

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No problem with snapping the disc mounting bolts, but the material seems soft as my hex head socket (Snap-On) wants to round out the fit. I've new spares (front and rear) on hand just in case there one strips-out.
 

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No problem with snapping the disc mounting bolts, but the material seems soft as my hex head socket (Snap-On) wants to round out the fit. I've new spares (front and rear) on hand just in case there one strips-out.
Are you using metric hex head sockets? I haven't had a problem with rounding the holes as long as I make sure the hex head is completely seated before turning the wrench. If an SAE hex head socket is used it will round them every time.
 

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Has anyone else had a problem with torqueing the 6 Allen bolts that hold each of the front rotors on the hub? If yes, has anyone approached Honda?

Sorry for the length of details, just want to be through and make sure no one is injured.

Thru various attempts and two tests, I've broken six out of the 12 bolts between the two rotors. Spoken to three Honda dealerships (Ontario, Canada) and a long time AT rider. Everyone is shocked and never heard of this before. When I ordered more bolts from my Dealer, Honda Canada only had eight bolts left in the warehouse. I asked why so little, he mused that nobody needs them. He's never had to order before. (I mused silently the reason is that we Canadians go thru so many!)

From my research these bolts I suspect are on many models of Honda bikes. So why are my bolts snapping like frozen butter? If this can help someone in the future, hopefully this will fast track your "adventure" and you'll get thru this faster than I have. Haven't been able to use bike for three weeks!! So far! Still not running.

Sequence of events:
  • first four bolts snapped while working in garage at temperatures ranging from +5C to -3C
  • after first two of those four, took brand new torque wrench back to Princess Auto for replacement. They checked wrench and said it was fine. I either set the wrench wrong or there is something wrong with bolts
  • carefully proceeded and the next two snapped
  • theory was too cold in garage, put all tools, parts and wheel in house at 20C for a week
  • note, Red Locktite used in all attempts
  • ordered more bolts from Honda at $4.91 CAD (approx. $3.89 USD) EACH after trying to find at more reasonable price elsewhere
  • still waiting to pu bolts from Honda dealership, ordered a package of 20 bolts from US for $1 USD each
  • in prep for new bolts coming thought I'd take the remaining bolts I have and put in three per rotor so I'd have at least those in while waiting for new ones
  • of those six bolts two torqued okay, four would not.
  • of those four that would not I broke two of them while trying
  • I even started at 10 ftlbs instead of the required 15 ftlb. Ten was okay, 11 okay, 12 okay, then broke at 13 ftlbs!! picture below of wrench setting


View attachment 60914 View attachment 60915

Possible causes:

  • substandard bolts got onto my bike somehow
  • too cold in garage making stainless steel too brittle, but same happened in 20C house
  • too much Locktite in hole preventing bolt from continuing to bottom, however each broken bolt did appear to make it to the bottom

Next steps:
  • install brand new Honda bolts - part# 90106-MMB-000 with remaining bolts I have.
  • during this install I will torque "sequence" each bolt starting at 10 ftlbs, then 11, then 12 and so on up until breaking or 15 ftlbs which ever comes first
  • I will reach out to buddies with small torque wrenches and compare my 15 ftlbs to their wrenches
  • depending how the above goes, I might replace all or some of the 12 bolts I've ordered here:


Ask of fellow AT Forum friends:
  • has anyone else experienced this? Heard of this? If yes, please post on here so that I can reach out.
  • purpose #1 is to see if I am "special" or if this is common
  • purpose #2 to prevent anyone from failing bolts causing crash and injury
  • purpose #3 prevent any fellow AT or other model Honda owners from wasting weeks of their life tracking down this bull ****
First, I will refer to ‘bolts’ but the correct term is ‘screw’. In this case they are button head socket cap screws.

Although the manual says 15, YOU are applying too much torque. Either your wrench is wrong or you lubricated the bolts (or both). Loctite is a lubricant. If you assemble the bolts with it wet you must reduce the torque. My manual does not refer to the bolts being aloc (already applied locking material) but it does say replace them if removed. This is because the high assembly torque is intended to place the clamp load beyond the elastic phase into the plastic phase. This is normally done to prevent loosening. Once tightened to this phase they are not reusable because when they are loosened they will not return to their original length. Although the bolts in my hub do not have head markings Honda must be specifying that they be made to 12.9 strength class or they wouldn’t withstand the high tightening torque. The way to legally supply high strength bolts without head markings is to provide them as proprietary parts, referred to by part number.

Also, you show an eBay listing for stainless bolts. If you are using stainless bolts they will not withstand that torque. Stainless steel bolts exhibit some odd strength (mechanical properties) characteristics. Test reports in our files show tensile strength similar to mild steel on up to nearly double that for the same chemical designation.

You mentioned temperature as well. Our test lab must be maintained at ‘room’ temperature (approximately 68F/20C) for consistency. Last week a local job site materials testing company reject a batch of large tension-control bolts. The bolts had been sitting outside on the job where it has been around freezing temps the past few nights. They tested them in the morning and claimed they failed. They were not aware the test criteria specifically states the bolts must be between 50F and 90F during testing. We sent them a copy of the spec’s. So they put them inside overnight and retested. They passed.
 

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I suspect your torque wrench.

Nominal Torque wrench accuracy is +/- 4% (check your specific version). This is as a % of full scale, so in your case 4% of 80 ft-lb or +/- 3 ft-lb. Better to use a torque wrench in the middle of rating not the bottom end.

Temperature won't make any difference to the materials in the range you are able to work on your bike.

I wouldn't torque sequence 10,11,12,13 ... sliding vs static friction ... I'd go hand wrench snug first, then 10 in a star pattern followed by 15 in a star pattern

Don't use red loctite on the Honda disk bolts - they are ALOC - the thread locker is already on the bolts. If you do reuse the bolts use blue loctite. Else you will need a heat gun or torch to soften the red lactate for removal.

Sounds like it's time to start over. Chase the holes with a tap to remove remnants of thread locker. Don't re-use any bolt you have already torqued with the suspect wrench.
Temperature won't make any difference to the materials in the range you are able to work on your bike.“
Your statement makes me curious. I have the equipment to test this. I could test the same batch of screws at freezing and at room temp with the same torque setting and see what the actual clamp load is.
 
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