attempted theft : no movement when in gear

[FinalImpact]

Both are induction hardened so other than the chain being so tight, its very probable both are OK.

- That said, you likely rode it with the nut missing and under load, that could have damaged the splines.

- If it were mine, the bare minimum would be nut, washer, and drive gear unless the gear shows NO signs of being loose on the shaft (think rotate for and aft in place. If it remains snug, you could reuse it. If its loose, you don't want to risk MORE damage to the shafts splines.

- Hopefully the threads are OK!

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With bike on center stand, throw block of wood under the rear tire so there is little to no gap.
Loosen axle nut, remove axle, slide wheel forward.
Remove front sprocket. Clean and inspect sprocket and shaft for wear, fit, and damage.

 

[mylo]

The chain looks tight in the video but in fact its very lose but ill order the washer n nut then ill do that remove the sprocket n check it out for wear or just do the lazy way n put the washer n nut n hope for the best

 

[2007Z6ALL-LED]

BTW, the front sprocket seems to be worn out..why don't you take the chance to get the new sprocket to finish the job at once? :rockon:

 

[mylo]

That sprocket is new . That was the problem the nut mustn't of been tightened properly when I got a new chain n both sprockets . I'll strip it down when I get a chance

Updated with new pics !! Looks like the threads are worn on the shaft :'( but the sprocket looks ok .. Video to follow

 

[mylo]

https://www.youtube.com/watch?v=sta70C-IiWM&feature=youtu.be video added of sprocket ..had to edit above thread as took forever trying to add them to tho on a windows phone as once I closed the manage attachments option the whole thing closes

 

[Motogiro]

It looks like you need a "V" shaped riffle file to clean the threads up on the end of the shaft. Work from the good threads out to the end of the shaft. If those threads are boogered and you don't get them right the new nut may cross thread on to the remaining good threads. If you don't know the exact hub height of your existing front sprocket as compared to the stock Yamaha FZ6 sprocket you may want to include the stock OEM sprocket when ordering your new OEM parts from Yamaha. This way the nut will meet the same height requirement when you punch the retainer into the locking slot on the shaft.
Remember that torque spec. is important and I would also clean those shaft threads with acetone and use semi permanent locktite on the threads. If you have a useable output shaft you want to do everything possible to insure you do this repair properly or you'll have a major tear down or loss.

 

[ChanceCoats123]

Yup, definitely put some kind of thread locker on there once you clean and put everything back together. Right now it's a few extra bucks to make sure it's right, but if it isn't right, it's a new transmission, or a new bike.

 

[FinalImpact]

You might just take a high density wire brush to it and remove the loose shards of metal. Careful of steel splinters.
If the threads have no peaks and are rounded that could be tough to correct with a metric thread file. Take a look here. These work pretty well BUT YOU MUST hold the angles true or the threads will simply be ground up without proper pitch to secure a nut.
Image - Thread pitch file
I'd guess you best shot is from the bottom up.
One other option is an actual thread chase die. Could be costly and hard to find. Visit a local repair shop and see if they have one or can help you out.
Good luck! PS - you know who to send the $bill$ too!

 

[mylo]

You wont get a die in there .. Well u can but you wont get a turn on it (I used to work with steel welding etc and there was a machine shop in the factory) to reshape the threads ! If u can take that shaft out you'd turn it easily on a die
I think ill bring it back to the guy who fit the sprockets and let him know I know its his fault this happened to the shaft for not doing the job right the 1st time . Surely nuts n washers dont just come off . I had the stock nut/sprocket on the bike nearly 6 years with no issue . Thanks again for all the input n advice

 

[TownsendsFJR1300]

Judging by the rust inbetween the shaft and sprocket, it hasn't been very tight for quite awhile...

I believe FI's comment re a file to the threads, is literally that, a file with the same thread pitch as the shaft.

Its NOT a die. You should be able to sneak it in there vertically and than rotate the shaft clockwise and CC with the file being stationary.

Good luck cleaning those threads, hopefully there's enough there...

 

[FinalImpact]

You might just take a high density wire brush to it and remove the loose shards of metal. Careful of steel splinters.
If the threads have no peaks and are rounded that could be tough to correct with a metric thread file. Take a look here. These work pretty well BUT YOU MUST hold the angles true or the threads will simply be ground up without proper pitch to secure a nut.
Image - Thread pitch file
I'd guess you best shot is from the bottom up.
One other option is an actual thread chase die. Could be costly and hard to find. Visit a local repair shop and see if they have one or can help you out.
Good luck! PS - you know who to send the $bill$ too!

I have a metric thread file with 8 different pitches on it. ^^ like in the link up there.

The Shaft is 20mm, the pitch is unknown but I suspect its 1.00mm ???
I don't see why a die won't work here. The proper holder for it may be an issue but there are work arounds.
LOOK! --> Thread Tools - Metric Dies
Not cheap tho....

 

[mylo]

You cant turn those dies as there's no room for the handle to turn the actual treads due to location of the shaft but the hex head could work if you didnt cross thread ! I ended up getting it towed n the guy fixed it for free . The new nut came with a large spacer washer which bypassed most of the damaged threads so I'm back on the road I threw the guy a tenner for the cost of the nut tho because I'm nice like that !!