Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: ted_paper on July 23, 2026, 05:48:58 PM

Title: Stripped thread
Post by: ted_paper on July 23, 2026, 05:48:58 PM
When tightening the front wheel axle clamp bolt nuts, one of them is refusing to tighten and just spins. Having tried different nuts I assume that the thread on the stud is stripped and needs re-cutting.
This would be my first attempt at using a tap-and-die kit and would appreciate any advice as to what size die I would need and can this be done without removing the leg?
Thanks 
Title: Re: Stripped thread
Post by: Bryanj on July 23, 2026, 07:29:35 PM
DO NOT try to rethread the stud, unscrew it and replace it
Title: Re: Stripped thread
Post by: ted_paper on July 23, 2026, 07:45:24 PM
DO NOT try to rethread the stud, unscrew it and replace it

Is there a reason for not rethreading the stud?
Title: Re: Stripped thread
Post by: K2-K6 on July 23, 2026, 08:24:56 PM
Usually, a stripped stud (male component) no sniggering the back  :D will have lost the outer diameter that forms the thread peaks securely. Thst leaving nothing to cut effectively.

Recutting would ordinarily require going down in thread size, for example 10mm to 8mm which would then make the stud undersized for it's designed stress loading.

Good quality "mole" grips tightly applied, or one of those proprietary stud extractor tools will just unscrew this one, to then let you install  new one.
Title: Re: Stripped thread
Post by: ted_paper on July 23, 2026, 10:33:08 PM
Thanks for advice.
New stud it is. :)
Title: Re: Stripped thread
Post by: Athame57 on July 23, 2026, 11:23:10 PM

Good quality "mole" grips tightly applied, or one of those proprietary stud extractor tools will just unscrew this one, to then let you install  new one.
I can't help comparing this to my non standard exhaust studs. The mechanic at the workshop I was using at the time advised me not to try and have them removed lest they snap off, which would be very complicated. I have a new set of studs gathering dust just now.  You mentioned 'proprietary stud extractor tools' which I've never heard of. Maybe the better workshop I rely on now could do the job or is it still probably  too dodgey? :-\
Title: Re: Stripped thread
Post by: K2-K6 on July 24, 2026, 02:39:49 PM

Good quality "mole" grips tightly applied, or one of those proprietary stud extractor tools will just unscrew this one, to then let you install  new one.
I can't help comparing this to my non standard exhaust studs. The mechanic at the workshop I was using at the time advised me not to try and have them removed lest they snap off, which would be very complicated. I have a new set of studs gathering dust just now.  You mentioned 'proprietary stud extractor tools' which I've never heard of. Maybe the better workshop I rely on now could do the job or is it still probably  too dodgey? :-\

I feel tbe first guy, and his advice, was from decent experience and quite wise. These are notoriously fraught for weakening, corrosion and often well "entrenched " in their little home position.

They can snap easily, and if functional along with being secure, you'd not offer to tackle them for no good reason.

The fork stud having much more important structural load, usually they are generally a bit oily too, makes them far more approachable to remove, also being next metric size up (from memory) have a larger core diameter and so significantly reduced risk of snapping when working on them.

The exhaust , if snapped, a right pain to work on, with little option but to drill out, giving you the chance to understand what fraught means in engineering terms  :)  ultimate failure often leading to head off, boring out properly on a milling machine (you might as well do them all while at it) to then fit a stepped stud or insert before further use.

I'd leave them be, assemble with generous amount of copper grease unless you've a concours winning example. 
Title: Re: Stripped thread
Post by: Athame57 on July 24, 2026, 08:03:18 PM

I'd leave them be, assemble with generous amount of copper grease unless you've a concours winning example.
I think these new studs I have will be gathering more dust then. If the head comes of eventually I'll consider the big job of fitting them so as to avoid a broken stud down the road.
Title: Re: Stripped thread
Post by: Mikep328 on July 25, 2026, 06:49:09 AM
There are two commons schools of thought re mechanical work - one is the "While you are in there" school which advocates replacing any/everything that can be accessed while you are working on some component.

And there is the "If it aint broke, don't fix it" school. 

In many years of working on cars/boats/motorcycles (vintage and otherwise) I have personally found the second to be the better choice.  As the mechanic who taught me a lot about such work when I was teen often said, "Sometimes the best thing to do is Leave it the F^$% alone!!!!"
Title: Re: Stripped thread
Post by: Bryanj on July 25, 2026, 09:26:59 AM
That comment is good EXCEPT when there are known problems that occur like 500 primary chain and dampers if the cases are split but not shells just because its apart, rarely wear and damned pricey
Title: Re: Stripped thread
Post by: Mikep328 on July 25, 2026, 09:37:44 AM
"That comment is good EXCEPT when there are known problems"

Totally agree!!!
Title: Re: Stripped thread
Post by: Otis on July 26, 2026, 05:21:48 PM
DO NOT try to rethread the stud, unscrew it and replace it

I agree but is there not also a danger that the internal female thread could be slightly torn as well?
Title: Re: Stripped thread
Post by: Bryanj on July 26, 2026, 06:07:48 PM
Not seen one yet and as its a standard 8mm it could be helicoiled anyway
Title: Re: Stripped thread
Post by: ted_paper on July 27, 2026, 01:07:36 PM
Old stud removed and new one ordered.
Just thought I might as well replace the nut as well but these are coming up at £3 ish for one - are they not just a 8mm nut or is it a special Honda thread?
Title: Re: Stripped thread
Post by: K2-K6 on July 27, 2026, 01:41:05 PM
Ordinarily std thread on there, but honda usually use a 12mm hex size instead of a std issue 13mm for this sized drive nut/bolt fitment.

You're right, high cost for single item, but ultimately the correct one is desirable in this case I feel.
Title: Re: Stripped thread
Post by: Bryanj on July 27, 2026, 01:44:51 PM
Correct its a non standard hex size but you can find 12mm hex with 8mm thread if you search
Title: Re: Stripped thread
Post by: 3scs on July 27, 2026, 07:02:39 PM
The correct nut is 8mm but it’s 14mm spanner size
Title: Re: Stripped thread
Post by: McCabe-Thiele (Ted) on July 27, 2026, 07:55:30 PM
FWIW the nuts on my 400 are 13 mm spanner hex.
Title: Re: Stripped thread
Post by: 3scs on July 27, 2026, 08:23:34 PM
Actually ignore my comment above that’s 550