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Rear sprocket install disaster


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  • Supporting Member
23 hours ago, petshark said:

I think that there was some kind of none-standard threadlock on both sides of the stud even though it is not in the service manual.

Might explain why the nut won that fight. Maybe you had mentioned it somewhere that I didn't catch, but was that sprocket original or a replacement? There was nothing on the threads when I did this work.

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canada.gif.22c5f8bdb95643b878d06c336f5fe29f.gif

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I love that we have a new verb; to overtighten and cause problems is “to petshark”.

”Read the manual, you don’t want to petshark that!”

”Use your own judgement as the values in the manual are too high, or you’ll petshark that fastener”

😂

  • Haha 8

Red 2015 Tracer, UK spec (well, it was until I started messing with it...)

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On 5/17/2021 at 8:58 AM, BBB said:

I love that we have a new verb; to overtighten and cause problems is “to petshark”.

”Read the manual, you don’t want to petshark that!”

”Use your own judgement as the values in the manual are too high, or you’ll petshark that fastener”

😂

That first example is not correct, sir.

petshark, verb, to strictly adhere to the manual's recommendations while disregarding that disaster is imminent.

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On 5/17/2021 at 12:46 AM, piotrek said:

Might explain why the nut won that fight. Maybe you had mentioned it somewhere that I didn't catch, but was that sprocket original or a replacement? There was nothing on the threads when I did this work.

It was original. I bought the bike with less than 5000 miles on it and it is the same design as on the official Tracer pictures. When I received the new sprocket I was amazed that it's teeth have no slope on the side. Is the below wear from misalignment or just a different design? I looks almost too crisp and symmetrical to be wear to me..

1711277087_Screenshot2021-05-18at13_30_45.thumb.png.22ee005c675578c2cdc38793a786b492.png

 

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7 hours ago, petshark said:

It was original. I bought the bike with less than 5000 miles on it and it is the same design as on the official Tracer pictures. When I received the new sprocket I was amazed that it's teeth have no slope on the side. Is the below wear from misalignment or just a different design? I looks almost too crisp and symmetrical to be wear to me..

1711277087_Screenshot2021-05-18at13_30_45.thumb.png.22ee005c675578c2cdc38793a786b492.png

 

That machined taper looks like an intentional design. 

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***2015 Candy Red FJ-09***

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13 hours ago, petshark said:

When I received the new sprocket I was amazed that it's teeth have no slope on the side.

Hmm...none? Can you post a photo?

canada.gif.22c5f8bdb95643b878d06c336f5fe29f.gif

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  • 3 weeks later...
7 hours ago, micah2074 said:

Speaking of rear sprocket disasters...fb_img_1622755028396-jpg.393359

Haha an old mate’s brother did that whilst oiling his chain on the centre stand.

He was scooping up engine oil with his hand and pouring it on the chain with the bike idling at 3000rpm in gear.

Natural selection won that day.

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On 5/18/2021 at 7:36 AM, petshark said:

It was original. I bought the bike with less than 5000 miles on it and it is the same design as on the official Tracer pictures. When I received the new sprocket I was amazed that it's teeth have no slope on the side. Is the below wear from misalignment or just a different design? I looks almost too crisp and symmetrical to be wear to me..

1711277087_Screenshot2021-05-18at13_30_45.thumb.png.22ee005c675578c2cdc38793a786b492.png

 

That taper on the teeth of the rear sprocket is correct and aids the sprocket in meshing smoothly with the chain.  If your new sprocket does not have this taper on the sides of the teeth my guess is that it missed a machining process and it will likely cause premature chain wear.  

There is nothing like spending a day riding with friends in the grip of a shared obsession.

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  • 9 months later...

My apologies for resurrecting this thread. I'm the OP and I have a direct question relating to this.To spare you from (re)reading the entire thread let me summarize it:

I stripped the threads on the studs and nuts when I tried to torque it to the specified tension in the manual. The torque wrench was of good quality and calibrated. I used epoxy to glue the most stripped stud back in and bought two new nuts from yamaha and tightened everything to a lower torque value.

While dealing with some damage from a drop I also sourced a used sprocket carrier that has done 15,000 km. (9320 miles). The studs and bolts are in good condition and I am preparing to install it.

But...

In this thread there was a lot of discussion whether the manual specs are ok or exaggerated and both camps had very good points. There seem to be many reports of people stripping the threads so I'm worried that it will happen again.

There was the interesting opinion that this torque spec means that you need to replace the nuts each time as you can only do this one. Another opinion was to replace the studs instead.

I had used WD40 so the studs were still slippery and may have caused me to over-torque and damage them. I will clean the thread with a wire brush and make sure that they are not slippery and maybe that will make all the difference.

But I'm again faced with the choice:

-buy new nuts and/or studs even though they look good to reuse?
-torque to manual spec or lower?

I'm not sure what I want to hear but just thought I'd throw it in the group once more because I'm really undecided.

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Saw something the other day about torque specs being dry.  Any lubricant will lower the torque and can lead to stripping bolts/nuts.  Think it may have been in a valve adjusting thread or maybe NGK spark plugs.  So based on that clean the bolts and make sure they are clean and dry then assemble to torque specs.  I replaced my rear sprocket at 11,000 miles.  It had very little wear and probably could have been re-used but I did not.  `A sprocket carrier with under 10,000 miles sounds like good as new to me.  

I torques mine to the torque specs with no problems and no lock tight.  Still good after 8,000 miles.  

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7 hours ago, PhotoAl said:

Saw something the other day about torque specs being dry.  Any lubricant will lower the torque and can lead to stripping bolts/nuts.  Think it may have been in a valve adjusting thread or maybe NGK spark plugs.  So based on that clean the bolts and make sure they are clean and dry then assemble to torque specs.  I replaced my rear sprocket at 11,000 miles.  It had very little wear and probably could have been re-used but I did not.  `A sprocket carrier with under 10,000 miles sounds like good as new to me.  

I torques mine to the torque specs with no problems and no lock tight.  Still good after 8,000 miles.  

That makes sense.

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I swapped my rear sprocket out this afternoon.  I had one frozen nut and ended up unscrewing the whole post + nut with a socket wrench with just a little resistance. One other nut was a little sticky. The rest were easy to unscrew by hand once I got them started with a socket. 

I was able to torque all of the nuts and the nut + post to the 58 ft lb torque in the manual. 

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