A reminder, a grade 5 bolt will flex before it snaps, a grade 8 will snap before it flexs, made from harder and stronger material than grade 5.
If you buddy was trying to looseing it, he could of twisted it and stared it on the road to breaking, I would lay the broken bolt back to that before blameing the bolt.

 

I'm sure he flexed it , so i'm better of back to the grade 5 ?

 

Don't put a grade 8 bolt in your shock mount, as said before; the grade 8 will snap before it flexes so use a grade 5 and snug it down. Personally I wouldn't consider using locktite in that position but if you insist on taking the shocks off to change a tire the repeated removal and installation could wear the threads, loosening the bond between bolt and frame threads.

Just run your axle through the left side of the swingarm and you won't have to ever remove a shock (or the exhaust) to do a tire change again.

 

Is the spring pre-load adjustable? If so, try backing it off a little bit.

A total WAG on my part, but it kinda makes sense to me.

 

Spring preload shouldn't do anything for the stress placed on the mounting hardware. When you increase the preload you simply just raise the ride height of the bike. The tension on the mounting hardware is the same.

 

Wrong as 2 left feet. Preload adds tension to the shock making it react harder and ride stiffer for adding a load, such as riding 2up. Changing height is just a function of making it stiffer.

 

Yes i will go with the grade 5 again , the factory manual said to unloosen the shock that why we did it ..

 

Not really correct.
A grade 8 will flex and break just as a grade 5 would and a grade 5 will fail before a grade 8.
Good reference here
http://www.rockcrawler.com/techrepor...ners/index.asp
That said the stock hardware should be sufficient, I don't see any identifying marks on the stock hardware.

Which loctite did you use, Blue or red? Factory uses blue so this causes a problem how? You should run a thread chaser through the tapped hole to clean it out and then add the loctite blue.
I agree with the second point for sure, sounds to me as if there was a failure due to the work performed on the bike.
When you go to remove the broken portion make sure you drill as close to center as you can and all the way though the broken fastener, this relaxes the broken fastener. I would start with a small diameter drill and move up successively in size to remove as much of the broken piece you can so you can use the largest extractor possible. After you get it out, use a thread chaser, not a tap as a tap will remove material, loctite blue and the proper torque and you're good to go.
CB

 

If you've changed your shocks for aftermarket ones (Progressive did you say?) and you're still using the standard length bolts, make sure the bolts aren't bottoming in the hole before they are actually tightening down on the shock spiggot. I'm not sure what the Dyna set up is having never had the shocks off mine but it's just a thought based on similar events I've seen happen in 40 years of engineering! Have you replaced ALL of the spacers / washers etc? Any left out or omitted would cause the same problem if the bolt goes into a blind hole - that is one with a bottom, and not drilled all the way through

Something is making this happen so you need to find the cause rather than just keep putting different bolts in there, the standard strength ones should be just fine for a decent road shock, I'm sure the HD engineers would choose the most suitable grade for most case scenarios!

Have you checked the I/D (inside diameter) of the shock spiggots _ the bit the bolt actually passes through is the same diameter as the orignal, if it's a slightly sloppy fit that wouldn't help matters

D

 

As a matter of course when changing a rear tire our shop replaces the axle from the left side. Whether a bagger, Dyna, sloptail or sporty. This allows any future change with the least amount of hardware disturbed.

The main rule of thumb is: never loosen/remove a bolt that absolutely doesn't have to be loosened/removed to perform the task at hand.

I think the reason for the bolt shear is two-fold: the most recent time was because your friend moved it and changed it's tension. Coupled with the rough road and the minimal travel of an 11" shock caused a shock load to the bolt and shearing it off.

The first time I am not familiar with to offer a diagnosis but if your riding conditions are consistent I would assume you are bottoming out your shocks on a regular basis. This bottoming out condition puts a "shock" directly to the mounting hardware they are not designed to deal with and as a result failure of the bolt is a natural occurrence.

Progressive shocks are not in any way a 'performance' shock, they are cheap knockoffs that people buy for the price point to allow them to get the "slammed" look so many of you desire. Increasing the pre-load on the springs will not increase the ride height or the amount of travel the shock is capable of. Increasing the pre-load increases the amount of weight it takes before achieving the 'sag' that is required to allow the shock to function in both compression and rebound conditions.

I would say that if the terrain you ride in is very poor you should consider an actual shock upgrade to any of the manufacturers that make performance shocks, progressive not being in that list. You should also go with a standard height shock to increase the amount of travel the shock is capable of thus allowing you to utilize the suspension to actually suspend the motorcycle and yourself from the road surface.

Good luck.