I think I remembering reading another post on this but it is worth repeating.

There are six studs that hold the rear sprocket to the sprocket axle. These studs loosened right out of the sprocket axle until I only had two left holding the sprocket on. This can happen even with the nuts properly torqued and the steel tabs bent over locking the nuts in place. Basically, the stud loosens out while the nut is held tight. This is a serious manufacturing defect that could result in a nasty accident or even death. Although there are the tabs to keep the nuts locked, there isn't anything keeping the studs locked into the sprocket axle except some locktite - assuming the guy at the factory was in a good mood that day at put it there.

My solution was to go to NAPA for some Grade 5 metric bolts that are long enough to bolt the sprocket into place without sticking through the sprocket axle so far as to rub the skid plate. You should still use the factory steel washers with the tabs bent over to keep the newly installed bolts from loosening. I used blue locktite also. I am currently searching for some case hardened metric bolts to replace the Grade 5 bolts.

I lost about 3 hours of riding time in the Hatfield McCoy trails after a 7 hour drive due to this problem with the Raptor. I am only thankful it didn't result in any injuries.

Hope this helps at least one person out there.

/NotuRaptor

 

Quick question for you, I'm not doubting what happened to you but how do the bolts loosen if they can not turn when the bent tabs are on them? Are they working back and forth and just stripping out of the sprocket? I'm just courious, I've checked mine a few times because I heard this before and they appear to be tight. The other thing I heard before was that the steering stem nut will loosen and fall off. Well I noticed some slop in mine and sure enough the nut loosened up but it would never fall off because there is a cotter pin that holds it from falling off but not close enough to prevent it from working loose.

 

The nuts themselves won't come loose per se (at first). The problem is with the six studs. The dangerous design flaw is that there isn't anything to lock the studs into the sprocket holder. If the studs vibrate loose from the sprocket holder, they will back out right through the nuts that are locked in place by the tabs. Basically, you are trusting that the studs will not come loose from the sprocket holder.

Instead of employing a multiply pieces to hold the sprocket on, Yamaha engineers could have easily just used bolts with the locking tabs. This method guarantees that it can't come loose. The current design as two ends that could come loose. The problem is that only one end is secured.

You are doing the right thing to keep checking them before each ride. I easily have 300 hours on my Raptor and it just happened all the sudden. Never had the problem and then boom.

/NotuRaptor.

 

had this happen to me too.The studs have threads on both ends an can back out of the sprocket
holder.the locks dont hold the stud from turning, just the nut. Take yours apart and you will
see what i mean.I only had 2 left the rest broke off.It tore my rear sprocket into 3 parts.I went
to the parts store and got automotive grade bolts.Dont know what they call them but they are super hardened and work great.I also used lock washers and lock nuts too.Anybody who reads this
should check them now because It could easily be fatal if it were to happen during hard riding.

 

not to change the thread but do u have a problem with ur axle nut lossing too?

i dont know wat to do ever time i ride i come back in 5 mins. with it off or lossed

 

Yes I have had problem with the axle nuts. I bought
an after market one off ebay for 35.00 bucks.
It has 2 allen head bolts that hold it in place.It doesnt loosen up now.It is worth the money.

 

Yea, I have that problem too. Been to the dealer a couple of times already and now heading back for the 3rd time this week. The only reason I am keeping after this is that I am hoping for a new axle. I am not going to go into the finer points of how two nuts twisted together form a lock but I will say that if the lock doesn't stay tight, the threads on the inside of the nuts and the axle can wear and thus never be able to form a proper lock (meaning you couldn't apply enough pressure to the nuts against each other to get them to get all the threads to bind).

Sneves, thanks for the info on the e-bay axle nuts. I was planning to order it if this next trip fails and I don't get a new axle and factory axle nuts. Do you need one or two of them?

/Jon

 

noturaptor

you might bring it up to your dealer that they changed the axel & nut in 2002 and you would like them to change your because of your problems .....might help!!

 

would the axle nut setup still work on the lonestar axle or should i wait to get a that lonstart locknut/hub thing with my axle?

 

Noturaptor,
You only need one bolt. It is about 2 inchs wide and willnot come loose if it
put on right.It comes with full instructions and is really worth the money.