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Discussion Starter #1
I had trouble finding a post with this info when I searched so I figured I'd make a new reference post so people can find this info easier.

The correct torque for the rear sprocket nuts is 43.5 ft-lbs.

The Factory Service Manual lists the torque for the rear sprocket nuts as 67.5 ft-lbs. This is incorrect and is corrected with a Suzuki Service Bulletin. Depending on the luck of the steel mill's draw, you may have studs that are strong enough to withstand this, but probably you will just shear the threads and end up with a spinning nut.

I'm working on getting a copy of the service bulletin to post, but you can get a summary of it here:

http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbresults.cfm?start=1&SearchType=DrillDown&type=VEHICLE&year=2006&make=SUZUKI&model=GSX-R600&typenum=1&component_id=0&summary=true&prod_id=216736&PrintVersion=YES

UPDATE: I recently purchased a hard copy of the factory service manual. Indeed, the newest revision of the FSM lists the proper torque as 43.5 ft-lbs.
 

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I had trouble finding a post with this info when I searched so I figured I'd make a new reference post so people can find this info easier.

The correct torque for the rear sprocket nuts is 43.5 ft-lbs.

The Factory Service Manual lists the torque for the rear sprocket nuts as 67.5 ft-lbs. This is incorrect and is corrected with a Suzuki Service Bulletin. Depending on the luck of the steel mill's draw, you may have studs that are strong enough to withstand this, but probably you will just shear the threads and end up with a spinning nut.

I'm working on getting a copy of the service bulletin to post, but you can get a summary of it here:

http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbresults.cfm?start=1&SearchType=DrillDown&type=VEHICLE&year=2006&make=SUZUKI&model=GSX-R600&typenum=1&component_id=0&summary=true&prod_id=216736&PrintVersion=YES
?? This past summer I tightened it to 67.5 ft-lbs.. hope it's still alright. I'll be putting new rubber on the 750 this spring for track days so I'll chat up the mechanic about this. Thanks for posting!
 

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Discussion Starter #4
Posted in Apr of 06, has the service manual been updated since?
The pdf of the FSM I have is dated 12/21/05. The link I posted above shows four service bulletins, all of which I believe are corrections (updates) to the original FSM.
 

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Discussion Starter #6
For those of us who have done it with the 67.5 do we need to undo it and redo it?
One method engineers use for determining the torque spec on a fastener is to set the spec at 2/3 of the torque required to permanently deform the bolt. Let's say Suzuki engineers used this technique, then 43.5 ft-lbs is 2/3 of what number? 65 - meaning if you torqued your sprocket bolts to 67.5 then there's a strong chance you've actually permanently deformed the threads on your studs, nuts, or both. What's bad about permanently deformed fasteners? They don't stay tight. You probably won't notice anything right away -- I didn't until the second time I tightened up all my chassis bolts and one of the nuts just started to spin. I figured one unevenly clamping fastener can warp the whole sprocket so I decided to replace it all.

The good news is, after I trashed the threads on my sprocket carrier, it took me a pair of vice grips on the nuts (haha) and pulling out as hard as possible to get the threads to engage enough to let me remove the nuts, so if you torqued to 67 it's not like your sprocket is just going to fly off randomly -- but it's not something I would let slide.
 

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One method engineers use for determining the torque spec on a fastener is to set the spec at 2/3 of the torque required to permanently deform the bolt. Let's say Suzuki engineers used this technique, then 43.5 ft-lbs is 2/3 of what number? 65 - meaning if you torqued your sprocket bolts to 67.5 then there's a strong chance you've actually permanently deformed the threads on your studs, nuts, or both. What's bad about permanently deformed fasteners? They don't stay tight. You probably won't notice anything right away -- I didn't until the second time I tightened up all my chassis bolts and one of the nuts just started to spin. I figured one unevenly clamping fastener can warp the whole sprocket so I decided to replace it all.

The good news is, after I trashed the threads on my sprocket carrier, it took me a pair of vice grips on the nuts (haha) and pulling out as hard as possible to get the threads to engage enough to let me remove the nuts, so if you torqued to 67 it's not like your sprocket is just going to fly off randomly -- but it's not something I would let slide.
I took mine off, and went with 50lbs. I will stay there, figuring in a little stretch on the bolts.
 

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Called Suzuki dealer in San Diego today. ( Fun Bike Center) about this.
He logged onto the Suzuki Dealer website then and there.
Indeed service bulletin 150 changes that torque specifically to 43.5 foot lbs.
They would have to be very strong bolts of that size indeed to survive 65 + ft lbs.
Real scary to think of the potential mess if they did seem to visibly survive then let go at
12K RPM or whathaveyou at whatever speed.
You deserver a medal for finding and posting this one !
It could save lives.
I was about to change sprockets within several days and it could have been a disaster.

Very well done for the post !

keep smiling and ride safe
 

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Discussion Starter #9
Called Suzuki dealer in San Diego today. ( Fun Bike Center) about this.
He logged onto the Suzuki Dealer website then and there.
Indeed service bulletin 150 changes that torque specifically to 43.5 foot lbs.
They would have to be very strong bolts of that size indeed to survive 65 + ft lbs.
Real scary to think of the potential mess if they did seem to visibly survive then let go at
12K RPM or whathaveyou at whatever speed.
You deserver a medal for finding and posting this one !
It could save lives.
I was about to change sprockets within several days and it could have been a disaster.

Very well done for the post !

keep smiling and ride safe
No problem man. Just for the record, though, I don't believe I'm the first to discover and post about this problem. Maybe the first to ask to get it stickied, but not the first sufferer of this circumstance. Anyways, I'm glad it helped you.
 

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No problem man. Just for the record, though, I don't believe I'm the first to discover and post about this problem. Maybe the first to ask to get it stickied, but not the first sufferer of this circumstance. Anyways, I'm glad it helped you.
It started with a member and myself having a discussion of him stripping one out. He and I called several dealers to confirm with results being mixed at first, then cleared up with a final result of 43.5 being correct. Minnesota dealers were slow to get the update.
 

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thanks lads although my chain and sprockets have just been changed ill be certainly writing down your info
Thanks again
 

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The torque spec for the rear axle nut is 100nm, but you may have to go a hair more to align the catsle nut for the cotter pin. Thats straight from the manual, and me an apprentice tech with three years experience. Ride smart.
 

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What about the front axle? It's also supposed to be 100 N-m but does that mean it's now 60N-m?

So far I've torqued everything at 101.5N-m give or take a bit to make sure it's tight.
 

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Discussion Starter #17
The torque spec for the rear axle nut is 100nm, but you may have to go a hair more to align the catsle nut for the cotter pin. Thats straight from the manual, and me an apprentice tech with three years experience. Ride smart.
What about the front axle? It's also supposed to be 100 N-m but does that mean it's now 60N-m?

So far I've torqued everything at 101.5N-m give or take a bit to make sure it's tight.
This thread has nothing to do with the axle nut. This thread concerns the nuts holding the sprocket onto the wheel.

As far as the front axle, the manual states 100 N-m for the axle bolt, and I am unaware of any service bulletins correcting this. Based on the size of the bolt, I would feel very safe tightening the axle bolt to 100 N-m.
 

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The torque spec for the rear axle nut is 100nm, but you may have to go a hair more to align the catsle nut for the cotter pin. Thats straight from the manual, and me an apprentice tech with three years experience. Ride smart.
72.5 lbs to be exact.
 

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My service manual says the rear axle nut needs to be cranked to 72.5 lbs- ft how can mine be so far off?
That is the correct number. What is so far off?
 
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