Help With Part Numbers Please - Sprocket Nut and Locking Tab Washer

[River Valley]

Looking to change to the 'safer' 12mm set-up.


Was reading posts on here about it and someone listed the required part number as 90891-101124, but when I did an Ebay search, the part number is shown as 90179-18006. Can someone tell me which, if any, is correct? or the correct one if neither.


Also, being a technical/mechanical numpty, what's the best/proper way to check the current nut condition? Is it simply take off a front sprocket cover (how?) and inspect? What am I looking for?


Thanks in anticipation.

[noggythenog]

Not sure about the part number but if you take off the sprocket cover and have a look it will be apparent.


The old nut will allow part of the shaft to be sticking out passed the nut whereby the new nut is almost flush.




You can actually shine a torch down the chain and squeeze your head round and have a visual check like that.....or describe what you can see on here.




P.S did you have any luck with your seat????......i have my seat that someone was interested in but they haven't messaged to say they still want it...i only want £20 for it and ive got a ye old local village post office so could do the parcelforce for you.?




Heres what the new one should look like.

[John Silva]

Looking to change to the 'safer' 12mm set-up.


Was reading posts on here about it and someone listed the required part number as 90891-101124, but when I did an Ebay search, the part number is shown as 90179-18006. Can someone tell me which, if any, is correct? or the correct one if neither.


Also, being a technical/mechanical numpty, what's the best/proper way to check the current nut condition? Is it simply take off a front sprocket cover (how?) and inspect? What am I looking for?


Thanks in anticipation.

Almost correct the part number is 90891-10124
Yes take the sprocket cover off and check to see if you still got an old nut fitted before buying new.

[unfazed]

Just checked the spare 12mm nut and tab washer kit I have and yes it is  90891-10124

Wemoto sell them http://www.wemoto.com/parts/picture/yh-90891-10124/

[River Valley]

Thank you all for the fast, clear and helpful replies. Confident I can check now.


Noggy - thanks for the seat offer. I'm fixed up now, as a guy on the ABR forum had one which he despatched yesterday via Parcel Force. Any hiccups with that and I'll get back to you.

[River Valley]

Not quite as straight forward as I'd thought .....


Looked easy enough to remove sprocket cover, gear change linkage arm and the 4 retaining bolts, but, my Haynes Manual then says .....


'Discard the gasket as a new one must be used'


I can see the gasket. So you have to replace the gasket just in order to inspect behind the cover? What is that gasket actually doing? presumably, as it doesn't seal around the chain entrance to the cover, it doesn't form part of the general lubrication system? or am I being thick? Maybe it forms the seal behind the actual cover and chain (can't see it for the cover), so is needed as it seals the main engine oil?


Noggy - try as I might, I could not even begin to see the sprocket by shining my torch along the chain and attempting to peer in. What's the secret? 

[John Silva]

I've had the cover off many times and simply reused the old gasket and lost some of it and still no problems.

[andybesy]

Gasket doesn't do anything and doesn't need to be replaced. Only minor point would be that if it were to come away when you remove the cover then minor adjustment of the clutch lever may be necessary to account for new position of cover as the push rod mechanism connects in there and is quite sensitive. Should be able to do just on the handlebar end.

Another hint would be to mark the position of the gear shift lever mechanism so you can get it back where you're used to it, or even better now would be a good time to adjust if required... moving it down a couple of notches made a good improvement to my gear changes.

Expect to feel the need to give the area a good clean up when you see inside! It can be a bit of a shocker!

I'm not very mechanically confident but even I managed this one, you'll be fine.

Andy

[andybesy]

Couple of other minor points, if you do decide to clean the area then take care not to stick a screw driver or whatever you use to scrap away the crud through the seal around the gear shift... it can be hidden by crud but  be gentle until you can see what's underneath.

Also as well as the Alan bolts there are a couple of dowels, mine never dropped out but careful not to loose them. And place the alan bolts down in an order you take them out as they are not all the same size. Only just nipped up hand tight is fine for doing them up. Bit of copper grease good idea.

Andy

[unfazed]

Take note of where the punch mark on the gear shaft is located in relation to the slot on the linkage.

If you have the linkages adjusted to suit you then make sure it goes back in exactly the same position.
A spline out can mean the difference between a smooth gear change or a notchy one.

[limax2]

Not quite as straight forward as I'd thought .....


Looked easy enough to remove sprocket cover, gear change linkage arm and the 4 retaining bolts,

There are actually five retaining bolts. One about half down the cover and just in front of the frame tube.

[River Valley]

Thanks again everyone, what  a patient and helpful bunch you are.
Will 'av-a-go' and see what lurks .....