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Discussion Starter · #1 ·
Bought a 04 r6 a while ago but recently found out the sprocket nut was welded to the shaft, grinded the weld off because I plan on changing the sprockets soon and found that there’s no threads at all just smooth metal, I’m looking to rethread it with a die just don’t know which size. I know some people have done it before since this was a common problem for the 1st gen, so does anyone know what size die I should use?
 

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YZFR6... ooodles of HP
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There is not enough length for threads there. Bummer, but that output shaft is junk. Only options..

1. Weld a nut. Not recommend for safety due to proper weld technique and pre-load to sprocket

2. Replace output shaft
 
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Discussion Starter · #3 ·
There is not enough length for threads there. Bummer, but that output shaft is junk. Only options..

1. Weld a nut. Not recommend for safety due to proper weld technique and pre-load to sprocket

2. Replace output shaft
I could replace the output shaft but I wanna at least try to save myself the time of taking the motor out and taking it all apart, your right, there’s hardly any room to make new threads on the outside but I saw another post where someone drilled a hole through the center of the shaft and threaded it. I’m thinking of doing the same thing. I’ve also heard of someone using a lock collar to keep the sprocket in place, only issue is with the nut being welded it already started to wear out the splines a little since the sprocket had no pressure on it, it was pretty much just sitting there and all the nut was doing is stopping it from falling off, but it wasn’t tight at all, so I don’t want to make it any worse. Worst case scenario I’ll change the shaft it’s not a problem for me but like I said I wanna atleast try to save it. I’ll try drilling and tapping it and I’ll post any updates here
 

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The shaft is hardened.
 
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That is a center drill for turning and hobbing the splines. Try a cobalt drill medium speed light pressure and motor oil. See if it will make a chip.
 
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Don't try to rethread. I had this same thing happen on a 96 yzf600r. Spent a full day trying to get a die to bite and rethread. I came across an article on another page about a guy who had the same problem. He recommended the following repair and it worked perfectly and was super cheap.If you take Dremel and a small cutting wheel you can put on the new sprocket and tab washer in the splined portion of the shaft. Then take a Dremel and small cutting wheel and notch the splines all the way around then install a snap ring to hold it all together. I did it and the bike has racked almost 20,000 miles with no issues.
 

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Don't try to rethread. I had this same thing happen on a 96 yzf600r. Spent a full day trying to get a die to bite and rethread. I came across an article on another page about a guy who had the same problem. He recommended the following repair and it worked perfectly and was super cheap.If you take Dremel and a small cutting wheel you can put on the new sprocket and tab washer in the splined portion of the shaft. Then take a Dremel and small cutting wheel and notch the splines all the way around then install a snap ring to hold it all together. I did it and the bike has racked almost 20,000 miles with no issues.
Here's the link
 

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Discussion Starter · #10 ·
Don't try to rethread. I had this same thing happen on a 96 yzf600r. Spent a full day trying to get a die to bite and rethread. I came across an article on another page about a guy who had the same problem. He recommended the following repair and it worked perfectly and was super cheap.If you take Dremel and a small cutting wheel you can put on the new sprocket and tab washer in the splined portion of the shaft. Then take a Dremel and small cutting wheel and notch the splines all the way around then install a snap ring to hold it all together. I did it and the bike has racked almost 20,000 miles with no issues.
Thats a good idea but theres a downside to it, it might work if the splines are in good condition but mine arent as they have worn out a little from not having a properly threaded nut keeping pressure on the sprocket, so doing that would work for a while but i believe would slowly keep on wearing down the splines since there is quite a bit of slack in them already. Someone correct me if I'm wrong. Thanks for the suggestion though i just don't think it would work in my situation, it would work for anyone else though as long as the splines are good condition and dont have too much slack in them. I am going to try to drill a hole and thread the inside, instead of the outside, which should work as long as I can drill through it.
 

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If I were in your shoes, I'd stop by a motorcycle recycler and see if he'd let me swap motors with him. Hand him a few bucks for his trouble since he'll have to part yours out of course, but, you should be able to work a deal that doesn't cost you an arm and a leg and saves the hassle of dealing with it.

Just my .02
 

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Discussion Starter · #12 · (Edited)
Alright we’ll I made it work, got the new sprockets on just took it for a ride and it seems pretty solid but ima go easy for a while
to make sure the sprocket doesn’t come loose or anything. What I did was get one of those shaft collars that are split in half with the 2 bolts, and I welded it to the new sprocket so that it can clamp onto the shaft and it’s working great. The clamp I used was size m18 from ace hardware for anyone reading this who might try the same fix. Thanks to everyone for trying to help

EDIT: I only welded one half of the collar so the other half can clamp onto the shaft, if anyone tries this dont weld both of them
 

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Discussion Starter · #14 ·
Alright here’s a pic, so how I did it was put the sprocket on the shaft, put a 25mm washer on it since there’s a little gap from the sprocket to the end of the shaft, then put the clamp on there and tightened it while making sure it was completely flush to everything else. I then tack welded the washer to the sprocket all the way around, then welded one half of the clamp to the washer. You can’t see the weld in the picture since it’s on the other side. Been riding it for the past 2 days with the sprocket cover off so I can check it every once in a while, I’ve been up to 150 and it has not loosened or moved one bit. Just make sure that you put loctite on the clamp bolts and get them pretty tight but careful not to strip them since their pretty small bolts. Now whenever I gotta change the sprocket all I gotta do is get a new clamp and repeat the process, only takes 10 min or so. It might look real sketchy but it definitely works
 

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I would safety wire those bolts or nuts if they are nuts.
 
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Discussion Starter · #18 ·
Update: a month later the clamp began to get loose on the shaft, even tho the bolts were as tight as they could be, don’t know how but I don’t trust it anymore (guessing there just isn’t enough surface area to clamp properly). Ended up getting a big bolt (m18 if I remember correctly) cutting the head off, and welding the threaded part straight to the shaft. Had to rig up a little spacer out of some pipe but I made it work, all that’s left to do is cut off the excess part of the bolt so I can fit the sprocket cover and coolant tank.

(If the shaft looks crooked in the picture, it’s not, it is just the washer and spacer that are a bit off center)
 

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Discussion Starter · #20 ·
That chain looks rather lean... very much like a bicycle chain. Something like that may require more frequent replacement versus the stock 530/532.
Yea, its a 520. I plan on replacing it soon its really worn out and i just looked at it earlier and theres some rollers that are missing. Getting a new one asap
 
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