Sprocket bolts


14 replies to this topic
  • ssyz450fss

Posted October 05, 2010 - 11:55 AM

#1

My bolts and nuts are coming loses on my sprocket. how do i fix it? The Bike is a 07 yz450f.

  • Steel Panther

Posted October 05, 2010 - 11:58 AM

#2

make sure you are tightening the nut on the back and not the allen head, go in a star pattern just like the manual states. Also, some red loctite never hurts.

  • ssyz450fss

Posted October 05, 2010 - 04:56 PM

#3

usually hold allen head and tighten nut and was fine for some time, but then just came loose happens at random. It damaged the swing arm some. This only happened after i changed the stock sprocket.

  • rmcr250r

Posted October 05, 2010 - 05:10 PM

#4

make sure you are tightening the nut on the back and not the allen head, go in a star pattern just like the manual states. Also, some red loctite never hurts.


Thats how I do mine. Loctite does helps to....But your supposed to check those bolts before every ride anyways.

  • ssyz450fss

Posted October 05, 2010 - 05:12 PM

#5

I do and it makes me nervous to try and race it. I was wondering if anyone was having the same problem or if its just me.

  • johanssont

Posted October 05, 2010 - 05:24 PM

#6

Do you tighten the bolts to the recommended torque?

Red loctite is a little extreme, but if you are concerned it might be worth it for your peace of mind. Red Loctite is very difficult to remove once you use it. Green is stronger than blue. Red is for permanent installation.

I would buy new bolts and tighten them to the proper torque and check them occasionally. Overtightening can stretch the bolt and cause problems.

If they keep loosening there is something else happening. Maybe worn bearings or overtight chain?

  • ssyz450fss

Posted October 05, 2010 - 05:43 PM

#7

thanks ill try it.

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  • brentn

Posted October 05, 2010 - 06:34 PM

#8

Torque in a star patter with blue loctite. Mine have held up great since my sprocket change using this operation with 4 hours on the bike since.

  • grayracer513

Posted October 05, 2010 - 08:22 PM

#9

If they keep loosening there is something else happening. Maybe ... overtight chain?

Something you should look into. :smirk:

  • Polar_Bus

Posted October 06, 2010 - 02:07 AM

#10

I do and it makes me nervous to try and race it. I was wondering if anyone was having the same problem or if its just me.


I'm going to guess, the bolts loosened up, and you didn't spot the issue and kept driving the bike. The loose bolts have now oblong slotted the sprocket hub and or sprocket. Everytime you accelerate, then hammer the brake you are jarring the sprocket back and fourth. You need to closely inspect the hub and sprocket for excessive wear. BTW I am NO fan of loctite EXCEPT for sprocket nuts (I even go against my better judgement and use RED loctite ! )

This same scenario is common with rear spokes loosening up, if you don't catch the issue early, the hammering spokes will quickly trash the hub.

FYI when you see "black" near aluminum mated components, this is not good. This black color means aluminum is moving and rubbing against another component...

  • ssyz450fss

Posted October 06, 2010 - 09:03 PM

#11

ya the bolts came loose and tore through the side of my swing arm. know I'm looking at trying to fix it. would it be wiser to get a used swing arm or take this on to get welded?

  • grayracer513

Posted October 07, 2010 - 06:59 AM

#12

6 of one, a half dozen of another. If you have a line on a good used one cheap, get it. But a good TIG welder should be able to fix it, too.

  • beargap

Posted October 07, 2010 - 05:06 PM

#13

My guess would be the egged out hub holes. That's what mine was. I even replaced nuts and bolts, but they still came loose and trashed my hub AND case. Now I need to tear down and replace the case (expensive!!!!). Might be cheaper to just do the hub!!

  • partialperson

Posted October 12, 2010 - 10:52 AM

#14

Use 100% household silicone, the storebrands are ok. Spread the silicone around the bolts and even on the threads as you install them. The silicone has a bonding agent and will absorb shock and vibration also filling the gaps and voids. Y'all can make fun of my suggestion, but I guarantee it will work. Back in the 70's I had an issue with aircraft quality heimjoints and other locking nut assemblies. After months of experimenting this was the fixall.

  • Polar_Bus

Posted October 13, 2010 - 01:35 AM

#15

Use 100% household silicone, the storebrands are ok. Spread the silicone around the bolts and even on the threads as you install them. The silicone has a bonding agent and will absorb shock and vibration also filling the gaps and voids. Y'all can make fun of my suggestion, but I guarantee it will work. Back in the 70's I had an issue with aircraft quality heimjoints and other locking nut assemblies. After months of experimenting this was the fixall.



This is an "old skool" method for absorbing vibration harmonics. RTV is a great fix for exhaust springs that are prone to the ends snapping off from harmonics. Run a bead of silicone down the length of the spring, and no more broken springs. Never heard of using RTV on threads though....





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