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Baconandeggs
| Posted on Sunday, July 14, 2019 - 09:51 am: |
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I replaced the front isolator mount bolts recently as part of my build over the winter. I just had the bike started for the first time yesterday for about 3 minutes while still on the front stand. After I shut the bike off Looked down and the head of the bolt was laying on the floor. Both bolts snapped clean off where the head meets the shank of the bolt. Bolt type used: F911 Grade 9, 7/16x14 2-3/4 Install method using Don Casto’s page- Torque to 60 ft lbs, back off one full turn, return torque to 60. I have never seen a bolt respond this way even when working in cold temperatures. (These specific bolts were torqued when the garage temp was 30 degrees F. Does anyone have any insight or have had the same experience in the past with this type of bolt? If you can recommend alternative bolt sources or install methods it would be appreciated. I might as well update to a new isolator bracket while it’s torn apart. Let me know if you have one for sale. |
Ggggary
| Posted on Sunday, July 14, 2019 - 10:00 am: |
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No specific experience but 60 lbs especially if you used anti seize or other lube may have been a bit high. Retry at 45 lbs.? Fake bolts ARE rampant in the marketplace.... |
Baconandeggs
| Posted on Sunday, July 14, 2019 - 10:08 am: |
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I used a small amount of loctite red on the threads and a drop of motor oil on the base of the bolt head per instructions. |
Baconandeggs
| Posted on Sunday, July 14, 2019 - 10:22 am: |
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I used a small amount of loctite red on the threads and a drop of motor oil on the base of the bolt head per instructions. |
Steveford
| Posted on Sunday, July 14, 2019 - 05:33 pm: |
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From the X1 shop manual: Chase threads in cylinder head with 7/16-14 TPI NC tap before installing NEW bolts. Coat NEW bolts with Loctite 262 (red). Tighten bolts to 73-78 ft-lbs. You can get new bolts and washers from your local Hardley Abelson dealer. |
Screamer
| Posted on Monday, July 15, 2019 - 10:48 am: |
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The bolts may be bottoming out in the bolt hole before reaching proper clamp load. If all the “torquing energy” goes in to twisting the bolt rather than stretching it - that may contribute to the fracture. When installing the motor mount, install the bolts and washers without the mount (do not torque) until they bottom out. Then measure the gap distance from the head to the underside of the washer. Measure the thickness of the mount at the bolt holes - the mount needs to measure more than the gap distance. If it doesn’t, material should be removed from the threaded end of the bolts. Defective bolts, poorly calibrated torque wrench, non-flat mounting surfaces - may also contribute to the problem. |
Baconandeggs
| Posted on Monday, July 15, 2019 - 06:34 pm: |
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Wow, thank you for the insight. i just ordered new bolts from a different source, so hopefully that will avoid any QC issues. I’ll update you as I get back to it. With a good isolator and replacing all 3 bolts, do you think there is any reason to buy a Stenzel type brace? The isolator and bracket are from an X1. By the way. Thank you |
89rs1200
| Posted on Monday, July 15, 2019 - 08:39 pm: |
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Good Question! Any one else with experience with the Stenzel bar? I do! All three of my S3 have Stenzel bars. After 63,000 miles on one of the 1998 S3s, I freshened the top end with new cylinders & pistons due to oil leaks around the valve stems, and down on power. D'oh! Had a broken, left side, bolt. This is the one which always breaks! Rust revealed it had been broken for a while. the head of that bolt was still in there, holding on the one turn of threads! Bolt kit I had from American Sport Bike had a long statement explaining this bolt is broken because the original mount has a harmonic on that Left side. Stenzel bar does reduce vibration overall, but does it stop this bolt from breaking?! |
89rs1200
| Posted on Monday, July 15, 2019 - 08:42 pm: |
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Note concerning these two bolts. I have read, thread depth is important as threads are weaker than the non-threaded portion. Threads are supposed to end where the bolt leaves the head. |
Screamer
| Posted on Monday, July 15, 2019 - 11:32 pm: |
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During investigation of failures it was discovered that the bolts were bottoming out in some heads before achieving proper clamp load - even though the recommended torque was reached. Without correct clamp load, the bolt could rock and eventually break. Another failure caused by the bolt hole being "too shallow" is the right side bolt hole boss fracturing due to the bolt being torqued without clamp load resistance ("spreading" and fracturing the hole). We had seen several right side bolts also break. i've never used a Stenzel bar, but I've never had a mount bolt (or mount bracket) fracture since doing the gap comparison on each Buell I've owned or worked on. |
89rs1200
| Posted on Thursday, December 03, 2020 - 12:54 pm: |
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Motor Mount Bolt Kit instructions from American Sport Bike;
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89rs1200
| Posted on Thursday, December 03, 2020 - 01:09 pm: |
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Motor_Mount_Bolt_Kit-Buell_Recall_B018.pdf
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