Author Topic: Stripped axle clamp on front fork  (Read 397 times)

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Offline drumstyx

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Stripped axle clamp on front fork
« on: November 07, 2017, 12:39:17 am »
Was on the torque wrench at the specified torque, and snap....goes all loose! I was so close to having everything back together too!!!

So here's the question -- I know this has been discussed here before (http://forum.cog-online.org/concours-c10-zg1000-general-chat-and-tech/front-axle-clamp-bolt-hole-is-stripped/), and the main idea was the ghetto idea I had; throw a nut on a longer bolt, since it's just a clamp after all.

Now I know, a timesert or even helicoil is a better option, but here's the deal: I don't have access to a drill press right now, and I do not plan on selling this bike for quite a while, if ever...A nut on a longer bolt (by tightening the BOLT, not the nut) is valid, right? I mean, I know it's not a perfect solution, but timeserts are *very* hard to get in Canada, and the last time I did a helicoil without a drill press, I ended up with a slightly crooked thread (it still worked, but just isn't perfect, plus it's on a KLR so who cares, it's made to be cheap and dirty).

Gonna head to Fastenal tomorrow to get something for it, but I figured I'd ask here first anyway.

EDIT: Yeesh! Even helicoils are expensive for this: https://www.amazon.ca/Helicoil-5543-10-Metric-Thread-Repair/dp/B0002SRG34/ref=sr_1_1?rps=1&ie=UTF8&qid=1510019352&sr=8-1&keywords=helicoil+m10

There ARE cheaper threaded insert kits, but they're M10x1.5, rather than M10x1.25.
« Last Edit: November 07, 2017, 12:56:32 am by drumstyx »

Offline beaucephus

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Re: Stripped axle clamp on front fork
« Reply #1 on: November 07, 2017, 02:34:10 am »
What about drilling/tapping for an M12?  That would be around a $15 solution.
http://www.carbidedepot.com/formulas-tap-metric.htm

Offline drumstyx

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Re: Stripped axle clamp on front fork
« Reply #2 on: November 07, 2017, 06:58:41 pm »
What about drilling/tapping for an M12?  That would be around a $15 solution.
http://www.carbidedepot.com/formulas-tap-metric.htm


Thought about this, but I felt that would take too much material away. There are plenty of thread repair kits (knockoff helicoils...same stuff) at the local Princess Auto (Canadian Harbor Freight), but M10's only had 1.5 thread pitch! Yes, I know that'd work too, but if I'm going to the trouble of drilling, tapping, and setting a helicoil, it might as well be the right one.

So I had a look on ebay -- those same knockoff helicoils were available for around $15 for the correct M10x1.25...great! Ordered!

In the meantime, I put an order in at Fastenal for 2 60mm M10x1.25 hex cap bolts, and some M10x1.25 nuts. That'll work for now, and I'll helicoil it...at some point

Offline Sport Rider

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Re: Stripped axle clamp on front fork
« Reply #3 on: November 07, 2017, 08:40:09 pm »
I'd just go with the bolt all the way through as well.  as you say, it's just a clamp after all.   :great:
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Offline drumstyx

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Re: Stripped axle clamp on front fork
« Reply #4 on: November 07, 2017, 09:05:54 pm »
I'd just go with the bolt all the way through as well.  as you say, it's just a clamp after all.   :great:

The one problem is that it's not machined flat on the opposing side -- I *really* don't know why Kawi didn't just do it that way in the first place (I guess if you overtighten the through-bolt-and-nut, you could crack the whole lower, so I guess better to strip the hole). Seems these suckers can strip below the spec'd torque, and it'll become a problem for more and more over time.

Anyway, a washer takes care of it, but a 55mm bolt would be the *perfect* length in that case, and unfortunately Fastenal's options are either 50mm (about 5.5mm engagement with a 2.0mm washer) or 60mm, which would have ~7.5mm extra length. 50mm will do though, since there are 2mm of additional threading in the fork that haven't been touched, plus the 5.5mm in the nut, should be fine for now.

Online MAN OF BLUES

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Re: Stripped axle clamp on front fork
« Reply #5 on: November 07, 2017, 11:51:46 pm »
Well,
You already know my responses, from the last post on this subject.. and the happy outcome that person found..
Big dillemma cutting a bolt down and grinding the end, man, tough to fathom... :rotflmao:

Do yourself, and the next owner of your bike a favour... fix it correctly.
Ride safe, and best of luck.

Oh
And as its a KLR, I'll see to it that this gets moved to "other bikes" where it should have been posted.

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW

Offline drumstyx

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Re: Stripped axle clamp on front fork
« Reply #6 on: November 08, 2017, 12:12:34 am »
No no! This isn't the KLR, it's the Connie, I just mentioned that on my klr I did a helicoil freehand and it came out crooked....granted that was on the head with the engine in frame.

My plan is indeed to fix it right, turns out my dad has a drill press, but for now (late in the season, but my truck is in the shop for a week or so) I'll have to go ghetto.

Online MAN OF BLUES

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Re: Stripped axle clamp on front fork
« Reply #7 on: November 08, 2017, 12:40:27 am »
My bad... sorry...
With the wheel off, the lower fork tube can be turned sideways, and easily be drilled fot the tap for the insrt without undue consequences.. just do it sober, and don't hog the drill around... drill straight..

Best of luck.

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Offline drumstyx

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Re: Stripped axle clamp on front fork
« Reply #8 on: November 08, 2017, 11:23:08 pm »
My bad... sorry...
With the wheel off, the lower fork tube can be turned sideways, and easily be drilled fot the tap for the insrt without undue consequences.. just do it sober, and don't hog the drill around... drill straight..

Best of luck.

Ah, I didn't think of doing it sideways -- I was a little worried about keeping it straight if I had no level reference (flipping it forward it'd be angled with the head).

Considering the wheel has to come off anyway though, it's 4 clamp bolts and 4 bolts to take the fender off and actually remove the whole thing to put in the vice, so I might just do that anyway.

Doing it sober -- yeah, usually you measure shadetree jobs in # of beers, but maybe not this one :P

Offline ghostrider990

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Re: Stripped axle clamp on front fork
« Reply #9 on: November 11, 2017, 10:22:50 am »
Not pointing a finger at the OP for over-torquing the bolt.....

Is there anyway to avoid this, or do preventative maint. -- say, replacing these bolts, so this doesn't
happen to (me)???
Maybe with a stronger, hardened bolt-set??

Or was this just one of those 1/1000 things with a weak bolt??

gr
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Offline WillyP

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Re: Stripped axle clamp on front fork
« Reply #10 on: November 12, 2017, 01:31:10 pm »
Not a weak bolt, as the bolt didn't break... more likely the aluminum threads were worn out.

And as this turned out to be a Connie, can it get moved back to the appropriate section?
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Offline drumstyx

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Re: Stripped axle clamp on front fork
« Reply #11 on: November 15, 2017, 11:40:39 pm »
Preventative maintenance for this is probably pre-emptively installing a helicoil or timesert/keysert (although I never did manage to find M10 keyserts with the same pitch).

IMO, this is faulty design. If it actually needs those 26 ft-lb of torque to have enough clamping force, aluminum threads are inadequate, especially at such a fine pitch (1.25, vs 1.5 standard).

Of course, it's definitely a matter of wear over repeated removal, but as removal is necessary for ANY front end work, it's bound to happen to many owners. If you've got steel threads (helicoil etc), that'll make all the difference, since there's no sliding wear/stress on the aluminum, just pure tension in the direction it's meant to have tension.

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Re: Stripped axle clamp on front fork
« Reply #12 on: November 16, 2017, 05:19:35 pm »
IMHO that torque spec is incorrect, even tho its shown in the book... it is way to high for its purpose... I would never go beyound 15 ft/lbs on them.

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