Sprocket Bolts falling out

Hey guys

well i went riding yesterday and i have had a problem of a couple sprocket bolts falling out while riding an di have always wenta nd bought new ones so i finally put some lock tight on them and tightened them good. i rode for the first time in a bout 3 months. well i chekced before i rode and all of the bolts were tight. well i rode for about 30 minutes and accellerated out of a turn and heard a nasty crack and clank and the engine stopped an dthe rear tire locke dup and i slid to a stop. well all my bolts must have fell out but one. well my hub broke where it supported the last bolt hangin onto the sprocket and the sprocket looks kinda like a taco now lol. broke a spoke and bent a couple others. i think i will just buy the whole wheel assembly instead of goin through yamaha dealers.

oh i have imagestation but forgot how to post a pic on here using it. i know u get rid of one part of the link but forgot which one. thanks. i will post a pic of it as soon as possible.

Does anyone kno wwhy my bolts kept gettin lose? and has anyone else had this problem? thanks in advance for the info. Ride ON!

-Billy

Worked fine. Now click IMAGE, and paste that address there. Like this... Don't use the full address (orig) because they show up way big and take too long to load.

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BTW, DAMN!!! That looks ugly!

OUCH! Glad to hear you were able to come to a stop and not get thrown off!

What did you torque the bolts to?

Darryl

Hey

all i know is we just tightened them pretty tight. and used lock tight. used an allen wrench and didn't have an allen socket to measure the torque.

-Billy

Having been through this 2 times and several others being through it also this is what we came up with.

Once your bolts become loose, you ride a little bit and the bolts stretch and become fatigued from the torq put on them. So once you locktite them and retorq them the metal is all ready shot and the bolt will continue to stretch and eventually fail, as you found out.

Our solution has been to check your hub, the mounting holes, if they are ok, then buy new bolts, locktite, and torq to spec. Over torqing can stretch the bolts too.

I got lazy on my WR450 and didn't locktite the bolts right away. They got loose. I did the above, new bolts, and have over 1000 miles since then with no problem.

Throw any bolts left as far as you can so they never end up back in your new hub.

Yep - Endurodog is right. Once the bolts loosen up they will be very prone to loosening up again.

Buy a set of talon spocket bolts to replace your old ones with. They're a little higher quality than the stock yammie ones.

Recently replace my sprockets, all the talk of bolts coming loose on sprocket changes had me spooked. I made sure to clean them up well, lock tited them, and made sure to torque them to spec. My original have worked...... so far... about 150 trail miles.

Make sure you don't over tighten your chain,doing so can work the bolts loose by putting undue stress on the rear hub, which will make it flex and cause your problem with loose sprocket bolts. I have never had a sprocket bolt come loose, even while ice racing, which puts a TON of stress on the drivetrain. Remember " A loose chain is bad, a tight chain is worse" :)

Dave

Went through 3 different sprockets looking for a good ratio and haven't had any bolts loosen. I just torqued them to spec. No lock tight. Wheel alignment can have an effect on torque stress. Try to torque the nuts insted of the allen bolts. The sprocket has countersunk holes in it to keep the bolt locked in. If you are trying to torque the bolt it might bind and give you a false reading. 2cents

Q's for a bolt expert's...What grade bolts should we use? Should we use grade 8 that might rip the hub to pieces (I guess a grade 2 bolt could do the same if one bolt broke and the whole thing came to pieces), or should we use something that has a little stretch? :)f9dce960.jpg

I change sprockets all the time and have never had any come loose. As CronicArt said I don't think it's a good idea to torque them using an allen drive as the tapered head will definitely skew the reading. Better to use an extension (or crows foot) and torque the nut. MotionPro sells a "Torque Wrench Adapter" for ~$17 that should work nicely. I normally use blue loctite as an extra precaution.

Hey guys

thanks for all the info! so anyone have a rear wheel with sprokect and hub and everything in good shape they wanna sell? i figured i could probably buy everything together instead of buyin the individual parts from the yammie dealer and cost me a ton. since my sprocket is a taco now, does anyone have any suggestions on better ratios for the rear sprocket. well thanks again guys

-Billy

I would utilize a grade 8 bolt here.

The friction of the taper on the countersink will give you a bunko torque value, I like to lubricate the C/S with blue loctite and tighten the nut as mentioned before.

EBAY always has something on there for YZFs. I see wheels for sale all the time.

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