EVO All Evo Model Discussion

Graded bolts

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Old Mar 18, 2021 | 06:02 AM
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Default Graded bolts

Putting on a lower rocker box, I was snugging up the bolts when one of the 1/4-20 hex heads snapped off... I was using a 1/4” stubby ratchet with my fingers on the head of the ratchet. The good news is it didn’t wait until it was buttoned up and going down the road... the other good news; it snapped above the head, so when I removed the rocker box I was able to back it out with my fingers.
This is a grade 8 fastener... how the hell does a grade 8 snap so easily??!!!!!!
I picked up six new grade 8 1/4-20’s figured I’d replace them all. When I originally removed the rocker boxes two of the three 1/4-20’s were loose. Didn’t appear to have thread lock from the factory, not sure if thread lock will even help, due to the heat.

Softail axle adjuster screws; I believe they come from the factory with grade 5 fasteners. I placed ungraded Stainless steel hex heads in there. Is this a mistake? I figure the axle is locked down and the adjusters shouldn’t have much force on them and are only used for alignment or they would have one on each side of the axle. Am I wrong on this?
 
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Old Mar 18, 2021 | 06:22 AM
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Think of what your saying here, pissed at a grade 8 breaking, then you go to a lower grade bolt in other area of the bike. That rocker box could have been possibly cracked from a previous torque down??? Have a good look at it and you may see where it's been cracked previously, and just snapped as you turned it in. Yep, good it went there. As for the other area, bolts are spec'd out for a reason, your changing that to a non spec'd bolt.
 
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Old Mar 18, 2021 | 07:14 AM
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I hear what you’re saying regarding going to a non-graded bolt, when the factory chose a grade 5 for the task... but I also know that most of the engine covers use graded bolts and they’re changed out for SS, without issue, as a regular practice.
 
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Old Mar 18, 2021 | 07:16 AM
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I’m surprised those bolts snapped....there’s not much torque applied to those.

Speaking of Grade 5 and Grade 8 fasteners....my experience. I see Grade 5 stretch whereas the Grade 8 shears off.

When replacing bolts, pay special attention to the shoulder of the bolt. The shoulder itself was designed to carry the weight. An all thread bolt should never replace a bolt with a shoulder.

I’ve seen lots of people replace bolts with all thread.....then they wonder why the bolt breaks.

And nowadays with so much stuff coming from overseas....be very aware of ANY cheap fastener.
 
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Old Mar 18, 2021 | 07:26 AM
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Would you rather have a bolt that snaps clean and is easily removed or pulled threads to deal with?
 
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Old Mar 18, 2021 | 07:31 AM
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Originally Posted by EVOrider;[url=tel:19806685
19806685[/url]]I’m surprised those bolts snapped....there’s not much torque applied to those.

Speaking of Grade 5 and Grade 8 fasteners....my experience. I see Grade 5 stretch whereas the Grade 8 shears off.

When replacing bolts, pay special attention to the shoulder of the bolt. The shoulder itself was designed to carry the weight. An all thread bolt should never replace a bolt with a shoulder.

I’ve seen lots of people replace bolts with all thread.....then they wonder why the bolt breaks.

And nowadays with so much stuff coming from overseas....be very aware of ANY cheap fastener.
Good advice!
 
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Old Mar 18, 2021 | 07:45 AM
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Originally Posted by GOGOBECK
I hear what you’re saying regarding going to a non-graded bolt, when the factory chose a grade 5 for the task... but I also know that most of the engine covers use graded bolts and they’re changed out for SS, without issue, as a regular practice.
It might be "regular practice" but it is a bad one.

Why Can’t You Use Stainless Steel and Aluminum Together

Galvanic Corrosion

The combination of aluminum and stainless steel causes galvanic corrosion. In order to understand why you shouldn’t use stainless steel and aluminum together, we first need to understand how galvanic corrosion works. Galvanic corrosion is the transfer of electrons from one material (anode) to another (cathode). In addition to knowing what galvanic corrosion is, we also need to understand the technical terms that go along with it.

Here are all of the technical terms we will be using during this post:
  • Anode – material that is positively charged, electrons leave this material
  • Cathode – material that is negatively charged, electrons enter this material
  • Electrolyte – liquid that aids in the process of electron transfer
  • Corrosion/corrode – Destroy or weaken metal gradually

How It Works

Galvanic corrosion occurs when two materials (an anode and a cathode) come into contact with each other and an electrolyte. Electrolytes can be environmental factors such as humidity or rainwater. When these factors come into play, electron transfer will begin to occur. Depending on the level of resistance in an electrolyte, this transfer can happen much faster. This is why salt water, an electrolyte with a very low resistance, is a common factor when considering what product to use. Due to this, it is incredibly important to consider what material you are going to use in an environment. When working with a marine, salt water environment, you even need to consider the type of stainless steel you are using.

There are multiple kinds of rust that can occur during the oxidization process. To find out more about them please read this blog post about
 
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Old Mar 18, 2021 | 08:05 AM
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In my experience a good coating of anti-seize or thread lock negates any issues when using SS fasteners in aluminum... but maybe it takes more than two decades to cause a problem.
 
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Old Mar 18, 2021 | 08:38 AM
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Stainless bolts are generally weaker than grade 5. It's the nickel content that makes them stainless, but also weaker.

I wonder if Loctite helps with galvanic corrosion also? YD

 
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Old Mar 18, 2021 | 08:43 AM
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You’re right, as far as I know there’s no such thing as a graded stainless fastener. I try to be cautious as to where I use them, which is why I’m questioning myself on using them for the axle adjuster screws. I just can’t see how those screws are doing much after torquing the axle in place.
 
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