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So I finally got my manual for the 09...
One of the discs is very close to being out of spec runout wise, so I was reading up on the torque specs and stuff. Apparently, you are not supposed to re-use the old mounting bolts, but instead only use new bolts? Can anyone explain why this would be the case? I have always re-used nuts/bolts. Is it due to possible damage during removal (wrench to fastener) or is it actually something like metal stress/fatigue that weakens the bolts beyond a useful spec? It seems to be a common theme for many fasteners, but certainly not all...
 

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So I finally got my manual for the 09...
One of the discs is very close to being out of spec runout wise, so I was reading up on the torque specs and stuff. Apparently, you are not supposed to re-use the old mounting bolts, but instead only use new bolts? Can anyone explain why this would be the case? I have always re-used nuts/bolts. Is it due to possible damage during removal (wrench to fastener) or is it actually something like metal stress/fatigue that weakens the bolts beyond a useful spec? It seems to be a common theme for many fasteners, but certainly not all...
I managed to ruin one mine when I pulled the disc off for powder coating the rims. They were way tight and the allen hex hole is fairly shallow. I will reinstall mine with Loctite and they will be fine. Unless the threads are hosed up or you wallowed out the hex fit, I would not worry about it. Just properly torque them with Loctite.
 

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In the past I've always reused disc bolts but with modern motorcycles's search for low weight/low cost, I suspect the bolts are of minimum size and depth to save unsprung weight. When my wheels get Plastidipped with their first tire change the discs are coming off and new bolts used with their install per the manual. I don't think the Roadstar Warrior manual says replace the bolts.

Heating the rotor bolts with a torch then striking them hard with a steel hammer before using an impact wrench with a proper fitting allen key to break them loose works for me. Also, pay attention to which threadlocker you use when reinstalling, it has to be high heat tolerant.
 

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The bolts are one-time use because they come from the factory with thread locker. This is their way of ensuring that these bolts are properly secured by any Tom, Dick, and Harry. I've never used new bolts on my bikes. Just be sure to use Loc-tite (either a dab of red or a good helping of blue - your pick)!

Be forewarned, those bolts are tough to get off. An impact helps, but make sure you have the hex fully inserted. If it's off the slightest bit, you'll round it.
 

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Thanks for the tip, Nick, I'll reuse mine now.
 

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In some applications, bolts are actually stretched when proper torque is attained. Those bolts will be addressed in a manual as being a one use item. In aviation, I see them occasionally. The transmission to driveshaft bolts on the old BMW Airheads are like that.
 

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In some applications, bolts are actually stretched when proper torque is attained. Those bolts will be addressed in a manual as being a one use item. In aviation, I see them occasionally. The transmission to driveshaft bolts on the old BMW Airheads are like that.
yes. in the 09's engine (and those of most other bikes), things like rod bolts and cylinder head bolts stretch on proper torque application and must be replaced if removed.

for the rotor bolts i think it's more because of the factory loctite on them making them easier to damage on the way out and the fact that they're a critical safety component - easier to just tell you to replace them with new.
 

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In a production environment, the lowest risk strategy when it comes to critical fasteners is to use bolts with pre-applied thread locker. This eliminates the risk of too little, too much, or none at all. And worst of all, if Yamaha wanted to inspect this, they'd have to remove the rotors to ensure that the thread locker was applied. If you spec and/or control the bolts, you can get by with a quick visual inspection to minimize the threat of nonconforming wheels.

Then of course, there is the servicing issue I mentioned earlier...
 

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I give them a couple of good whacks with a brass hammer, then carefully crack loose by hand.

I would be hesitant to use impact, initially, but would after cracking them loose by hand, especially Allen's.
 

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iirc, they use blue loctite on the rotor bolts from the factory. i used a breaker bar to crack them loose, but i don't remember them being all that difficult.

on the other hand, i completely wrecked the sidestand switch bolts when i was trying to undo them. got them out about a turn and a half before i saw the reddish residue on the threads.
 

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The beauty of an impact driver is that you're only putting pure torque into the fastener - there is no threat of stripping the head if you have a good bit. This is literally the only way I ever remove rotors any more. Sounds crazy until you've tried it, though. I'll give you that.
 

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I reuse. I also ran a tap through the holes to clean out old loctite, and a die over the bolts themselves for the same reason. Apply new loctite before reinstall, ride long, prosper.
 

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Nick, it seems that I remember seeing some engineering standard about torqued bolts being a one time use thing. I'm like most everyone else, I reuse bolts like that, but just curious.
 

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The only technical reason you wouldn't re-use would be if they were torque-to-yield (TTY), which are the head and rod bolts that were mentioned above. Anything else is purely done for logistics, maintainability, and production.
 

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One of mine was so tight I bent an allen wrench trying to remove it. I used a short pipe to get enough leverage to bend it. I did eventually get it off and reused it.
 

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A bit off topic..

The new R1 uses Aluminum bolts all over the engine. They are strictly 1-time use because you can never re-torque them a second time. So if you want to install a case saver or replace a case cover, you have to replace the bolts and they are not cheap. I wonder how many 10th's that saves on a lap time.
 
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A bit off topic..

The new R1 uses Aluminum bolts all over the engine. They are strictly 1-time use because you can never re-torque them a second time. So if you want to install a case saver or replace a case cover, you have to replace the bolts and they are not cheap. I wonder how many 10th's that saves on a lap time.
I've been eying up that kit for the FZ...
 
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