Front sprocket nut - size?

[pointer2null 106]

Going to be changing the chain and sprockets this weekend weather permitting...

 

What size is the front sprocket nut?

What is the torque?

 

Thanks

[Dunnster 1,650]

Sorry I can't remember the sprocket nut size but here are the torque values.

Gearbox sprocket bolt torque 54Nm

Rear wheel sprocket nut torque 108Nm

Wheel spindle nut 98Nm

Hope that helps. 

 

 

[CFB 4,601]

IIRC, the front sprocket nut is 12mm

[Guest machinman]

1 hour ago, CFB said:

IIRC, the front sprocket nut is 12mm

Could be 14mm??

[Guest bonekicker]

Could be 13mm??

[pointer2null 106]

Um... ok..... Front sprocket nut on a similar bike is around 38mm and has a torque around 112NM to give an idea.

[Mr Toad 9,022]

Are you going for the same number of teeth on the front or going up/down a tooth?

 

[pointer2null 106]

same - current ratio seems ok to me for commuting

[pointer2null 106]

14mm - just had a look.,

[kayz1 2,928]

Book of words for the 700 says

Drive sprocket bolt:  qty one: Size 10:   n-m 54.    ibs.ft  40

[rjp996 1,091]

Changed a few on mine and the nuts have been easy to get off - just remember to loosen the nut before takign the rear wheel off - done that twice and still not learned ;-). I just get my wife to sit on the bike with the rear break on to loosen

[embee 7,288]

... and in case you wonder, the bolt/washer don't clamp the sprocket tight, it remains free floating on the splines, only a mm or so but it is free to float. I use moly60 paste on the splines FWIW.

[michael 324]

14 hours ago, embee said:

... and in case you wonder, the bolt/washer don't clamp the sprocket tight, it remains free floating on the splines, only a mm or so but it is free to float. I use moly60 paste on the splines FWIW.

great idea, lubing the splines.

I've read  (I get to read recreationally every now and then) the  Honda XL650 tends to chew up the drive splines if not lubed during sprocket changes. I can't see any reason why it couldn't happen with the NC.

 

(yup, I lubed mine as well at the last sprocket/chain change).

[pointer2null 106]

Still no idea what the torque is for this?

[Mr Toad 9,022]

21 minutes ago, pointer2null said:

Still no idea what the torque is for this?

 

Posted further up.

 

23 hours ago, kayz1 said:

Book of words for the 700 says

Drive sprocket bolt:  qty one: Size 10:   n-m 54.    ibs.ft  40

 

In addition to the 54Nm for the front the rear axel should be 98Nm, I believe that's what it says in the manual.

[pointer2null 106]

I saw that - so I guess that size 10 === M10 thread?

[Mr Toad 9,022]

4 minutes ago, pointer2null said:

I saw that - so I guess that size 10 === M10 thread?

 

I would say so yes. Normally if it's an M10 nut or bolt then it would be 17mm spanner/socket and that used to be the standard, however, I have M10 bolts with a 15mm head so maybe the standard is changing or some manufacturers are making them smaller to save a few pennies per million bolts?  

 

On my Triumph Bonneville the front sprocket is held on by a 36mm nut.  

[Tex 36,817]

I don’t believe it’s a cost cutting thing. I think (but don’t actually ‘know’) the reason for making the head a smaller size is to discourage the careless amateur from over tightening it. 

A Neanderthal faced with a large nut will heave on it..

[embee 7,288]

It's primarily to save weight/material, but also means lower cost. Might not seem much each, but if you're using a few million bolts a year, every little helps. Plus the use of smaller head sizes means smaller tooling so less space required for access etc. It also works better with flanged (washer faced) fasteners, which usually provide better load distribution under the head and better load retention in the joint, loose washers are generally a no-no in volume production. Fasteners are a whole discipline in themselves.

[Tex 36,817]

There we are, now we all know. Thanks Murray.

[pointer2null 106]

All done.

 

Getting the back wheel back on was a pain, but otherwise straight forward.

 

Think I'll invest in a better chain riveter for next time though...

[gonzo 2,211]

Gary, how many miles did you get out of the original chain/sprox and have you an auto chain oiler fitted, just asking,.!!!

[pointer2null 106]

Around 12,000.

 

After I remove the old chain I checked it over, there were a few tight links but nothing I'd say was seized. 

 

I could probably got more out of it - maybe a fair bit, but the time between adjustments was starting to decrease rapidly and I could hear clunks and other odd noises. So for the sake of £80 I know it's all fixed now.