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Discussion Starter #1
Hi quick one just wanted to confirm that the front sprocket nut is a rh thread because its so tight even with the rear brake on and an impact wrench. I know its about 125 NM but still previous owner probably never changed it or if he did never used moly grease so might have corrosion present.
 

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2013 Ninja 650R
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it is but the factory must really crank them down. many threads out there about having trouble getting it off for the first time. obviously, make sure the washer under the nut is knocked flat. one step in re-install is bend flange of it up to act as a lock to the nut. when i did mine, i had to borrow a more powerful impact wrench than i had.
 

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2011 Kawasaki ER-6F
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67 Posts
Yea all of these styles that Kawasaki uses are on there like mad.... both on the 650 and even the 300. When it was time to do mine we needed a 2m scaffolding tube over the breaker bar. The nut likes to FUSE with the locking washer so try to see if you can use a thin screwdriver or something between the 2 to try to separate them a little.
 

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Put a sturdy piece of timber wrapped in some towels through the back wheel to lock it to the swingarm.. Make sure you've flattened the washer back against the sprocket (it should be folded down).. Garages just seem to tighten them until the world ends.. Make sure the bike's out of gear or you run the risk of damaging the gearbox - an impact wrnech should get it off with a few good goes.. Let us know how you get on - there are more extreme methods (like using a dremel to cut the nut so it can be broken off... Or maybe take it to a garage and ask them to crack the nut (some may even do it for no charge) tighten it enough to get home and then sort it..)
 

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I had one that took a bunch of heat, my buddy who weighs a good 250+/-, and a good 4ft bar to finally get it off. Took at least a half hour of multiple other methods including NASCAR capable air supplies for the pneumatic tools that did not work.

I don't know why people put them on this crazy tight. If I remember correctly, the manual only calls for about 95lb-ft of torque which is not all that hard to break. Perhaps people just forget to add the oil/grease mixture on the threads that the manual calls for.
 

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Discussion Starter #7
Tried the wood trick with torque wrench and electric impact wrench to no luck so i think its off to the workshop. :mad:. In the mean time spraying fairings and tank and clean out tea bag filter whilst its off.
 

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Discussion Starter #8
Well that nut is truly stuck. Tried with a 720nm air impact wrench at 10 bar air pressure, after heating up the nut with a hot air gun and still no movement.Looks like I'll have to slit the nut with a dremel and cuting disc and a nut splitter. Anyone got the part no for a new nut.
 

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Well that nut is truly stuck. Tried with a 720nm air impact wrench at 10 bar air pressure, after heating up the nut with a hot air gun and still no movement.Looks like I'll have to slit the nut with a dremel and cuting disc and a nut splitter. Anyone got the part no for a new nut.
Don't do that - it's a $40 + nut. Immobilize the rear wheel, or lock the chain together to keep the works from spinning. Put a good quality 1/2 inch breaker bar on it and get a cheater bar at least 3 feet long. I used a jack handle that's 4 foot. Set it in the 10 o'clock position and use your weight to pull down. Don't jerk it, just keep constant pressure and it WILL break free.

And this has very little to do with how much torque was applied when mounting the bolt. I've had this issue every time with my 650 (I've done 4 sprocket changes) and it's never gotten any easier and I KNOW that it wasn't super-torqued on reassembly because I did the change out myself. Someone on here must be knowledgeable enough in metallurgical sciences to explain how it happens.
 

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2011 Kawasaki ER-6F
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Don't do that - it's a $40 + nut. Immobilize the rear wheel, or lock the chain together to keep the works from spinning. Put a good quality 1/2 inch breaker bar on it and get a cheater bar at least 3 feet long. I used a jack handle that's 4 foot. Set it in the 10 o'clock position and use your weight to pull down. Don't jerk it, just keep constant pressure and it WILL break free.

And this has very little to do with how much torque was applied when mounting the bolt. I've had this issue every time with my 650 (I've done 4 sprocket changes) and it's never gotten any easier and I KNOW that it wasn't super-torqued on reassembly because I did the change out myself. Someone on here must be knowledgeable enough in metallurgical sciences to explain how it happens.
Funny enough mine likes to come loose on it's own every couple thousand miles lol even with red threadlock... As i said originally they like to fuse with the lock washer probably due to heat and corrosion.
As for the nut, just buy a used one, it's the same nut for a lot of models, ninja 300, versys, i think even the older zx6rs use the same nut and those can be had for around 10 bucks.
 

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Discussion Starter #11
Tried again with power bar and extension pipe still no go. New nut arrive today so tomorrow its out with the dremel to carefully slit the nut on both sides and a cold chisel .
 

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Tried again with power bar and extension pipe still no go. New nut arrive today so tomorrow its out with the dremel to carefully slit the nut on both sides and a cold chisel .
Good luck, sometimes it is like that with things like this :/
 

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Discussion Starter #13
Success. I think I've discovered the causes for nut being so tight even though gear box shaft threads are perfect with no rust.1) The back of the nut is recessed for the shaft splines. 2) When tightening the nut the splined lock washer is held by outer edge the nut, whilst the inner edge of the washer is slightly deformed into the nut spline recess. This causes the nut to bind to the washer even when the tabs are not bent. I have put copper slip on the shaft, washer and this inner flange of the nut.
138129
 
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