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Front Sprocket Nut

37K views 51 replies 22 participants last post by  asdfjklm 
#1 ·
I pulled off all my stuff to do my 520 conversion and my front sprocket has NO nut on it. WTF? Of course no one can get it to me for about a week. Do you think i can go to a hardware store and find one that will hold it until then? I want to take advantage of this beautiful weather.
 
#2 ·
You didn't have any nut at all?!?!? How many miles have you put on your bike with it in this condition? I'd consider yourself damn lucky to be alive.

But yes, I regular nut will work. Just make sure you use blue loctite on it until you get your OEM nut.
 
#6 ·
Can't help with the size but I had the same thing happen to me when i did the conversion. I also have a 2001 R6 and when i went and ordered the part the mechanic acted like he has seen this before....weird. I guess the sprocket case is what kept the chain from flying off. +1 for the blue locktite and the nut will also come with a fold over washer. Good Luck
 
#8 ·
Same thing happened to me when I had my 01. I took the front sprocket cover off to do the 520 conversion and the nut was missing :eek5
I don't know if it came off when I owned the bike or when the previous owner had it. I probably put over 5,000 miles on it before I did the conversion. I just can't believe the chain/sprocket didn't go flying off.
 
#9 ·
My front sprocket actually came off of the drive shaft last year due to the same issue. Luckily there was no damage. But, note that the lock washer does not come with the nut, they should be ordered separately. I order 8 of each last year and now keep one of each in the under seat storage along with a 32 socket :) I'm a paranoid f#$@

Also note that you will almost definitely not find an appropriate nut for the drive shaft in a hardware store. I had to have a nut made and a washer laser cut for me. I noticed that the pitch of the drive shaft is not exactly standard. Don't strip your shaft out of impatience. Get a caliper and measure the thread width and depth, make sure whatever nut you get from a random store corresponds.
 
#20 ·
Where did you order from? My dealer said a Yami dealer has to do the work.

What would I need to take off to check, or how would I feel for if the nut is there or not? Is there a DIY out there for this?

My 05 has 9.4k on it now, but I don't think I have the mark after my VIN that it was done; should I be worried about it?

Where can you get a cover that lets you see the nut?
 
#12 ·
wow - how did I not think of that one?

I hasn't happened to me since that time last year, but I'm always prepare for it. Plus I feel for my washer and nut every washing, which is about every 2 weeks in the winter. It's definitely a big paranoia issue for me - I might have to get therapy one of these days because it's becoming compulsion. Freaks me out that other people have had this problem too - now I might have to check my nut more often.

Mine also disappeared on a high speed run (I assume it disappeared because I actually never checked it until my sprocket came off of the shaft). It was one of my best rides on street, it was flowing like butter; then waaaaaahh ... nothing.

That safety-wire suggestion is a good one - I'm gonna do that to one of my spare nuts and try it out. Although I find that using an airgun + blue loctite has since kept my nut in place.
 
#13 ·
i wouldnt suggest a hardware store nut...the threads in a industrial nut are not as fine as a machined nut and can ruin the threads on the bolt. i know its hard but id be a lil patient if i were you
 
#21 ·
i know this is an old thread, but this shit has happened to me recently. i dont know how long they have been missing. i was having trouble keeping my chain slack adjusted. i just chalked it up to chain wear and that my chain was about done. i posted a while back asking what the life was on the chain, thats prolly when it first fell off. been months. anyway, today i washed the bike and was running the rear after adjusting my chain AGAIN. so i look down the chain for straightness and i hear like a clatter in the front almost like the chain was skipping a tooth. im all like how the f can that be when i just tightened the god damn thing. so i removed the side cover and the sprocket cover. no washer, no nut, and a beat up looking front sprocket. i know for a fact i torqued the nut, used blue locktite, and bent the washer like you are supposed to. the only thing i didnt do was use a "new" washer. how the hell does a locktited, torqued down nut just fly the hell off and out without getting caught up and locking or destroying the transmission? anyway, also noticed what looked like metal shavings, very fine metal shavings, almost like dust on the swing arm where the chain slap guard or whatever it is on top of the swingarm. well anyway, be aware that those shits can come off and seems like could be very catostrophic. luckily i kept my sprocket guard on and i guess that kept it from flying off.
 
#22 ·
The metal shavings are probably little pieces of your output shaft thread. Don't worry though - it's pretty tough; which is why they're dust-size pieces.

Get some alcohol based cleaner - or user carb cleaner, and clean up the thread of the shaft. Get a new nut and washer. Go to a shop that has an air compressor and a gun and loctite it on with the air gun; fold in your washer, leave it for a few minutes, and you're good to go. If it falls off again after that, you've got terrible luck.
 
#23 ·
Whats the benefit of using an air gun vs torqueing it to desired spec? Just to over torque it?

My dealer said they can do it but can't watch, and won't even let me buy the replacement kit, Said he can try to order the 2 parts separately, but I'd be worried it could be the old nut/washer again.
 
#24 ·
So order them your self and bring them to the dealer in the package - it'll have the yamaha part number on it, so that can't give you any bullsh!t.

I ALWAYS use an airgun on any part of the bike that turns the motor/tranny directly. It takes away any chance that you miss-torqued due to lack of resistance from the turning part. I'd hand torqued a sprocket nut before - torqued it to specs with a 2x4 wrapped in towels between the wheel and swing-arm. Not going to bother trying that again - it just shouldn't take that much effort and rigging - plus the nut eventually backed off.

I went to my mechanic's garage and I did it there with his compressor and it hasn't backed off since.
 
#26 ·
Wow, I missed this thread when it started. I guess I'm not the only one to have this happen. Unfortunately this happened to me whilst I was riding, at speed, in a turn, and I lost ALL power and almost spilled.
I had to order the nut, washer AND I had to purchase a Die, just to re-thread the drive shaft. The motor was spinning so fast, that when the nut stepped off, and the sprocket stepped off, it flattened the dang threads.
Everything is fixed now, but you better bet your ass that I check that shyt every time I do the oil. It HAS BEEN blue loc tite'ed AND similar to Varna, I have a spare and a socket just in case. (But I don't have 8 of them.)
 
#27 ·
yeah, fortunately nothing happened to me while riding. i would guesstimate i have put over 1000 miles on since i had the chain slack problem. my threads are good but it amazes me that the nut and washer made it out without causing and other damage. the wear on the front sprocket seems like its just from riding side to side along the shaft. its crazy though how many people have posted up that this has happened to them. going to get an impact wrench for my compressor from sears and try to find a 32mm impact socket somehwere. hopefully they got that there too.
 
#28 ·
Sorry to resurect a thread this has just happened to my 06 r6!

The thread towards the end is ****ed. Have ordered a new nut which comes 2moro but im not holding out much hope that it will go on.

Please can somebody specify which die kit size etc i will need to rethread the shaft! im clueless as to how to do it! cheers

kev
 
#29 ·
I can help you out when I get home. I actually HAD TO buy the die to fix my threads as well.

I get out of work tonight at 10P central. I will be home shortly after. I SHOULD have the info up for you by 11P tonight. If you aren't on at that time You can check it first thing in the morning...

OH DANG! I see that you are in England. You probably won't get my info until tomorrow morning.
 
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