Overtorquing the swing arm

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octaman
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Overtorquing the swing arm

Post by octaman » Tue Mar 27, 2018 8:18 am

Hi everyone,

Had a puncture recently while riding in the city.

There was a tyre shop just across the road, so pushed my scooter to it to have the tyre fixed.

As I was watching, when the wheel went back on, the guy used one of the those air tools to tighten the bolts (!)
When he was done I just had the feeling that the two swing arm bolts (with washers) had been overtightened.

So, I went back home and into the garage and set about to check; first with my torque wrench set at 49 Nm I tried to tighten. The bolts would not go any further. Then I tried to undo and remove the bolts. The bolts initially were very difficult to untighten and then came out with difficulty right to the last turn.

My guess is that the thread in the motor housing has been deformed.

I put the bolts back in and tightened with my torque wrench set at 49 Nm. The feeling was that the bolts went on and on a bit after going completely in place before the torque wrench clicked 'okay'.
I am now seriously worried that the thread(s) have been destroyed.

Has anyone had a similar experience and what did you do about it?
Does anyone know if it is dangerous to ride the scooter in this state with risk of the swing arm working itself loose. Or should I refrain from riding until I have the issue rectified?

I look forward to your views and opinions.

Octaman
Ride safely, feel free

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TommyXP
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Re: Overtorquing the swing arm

Post by TommyXP » Tue Mar 27, 2018 8:32 am

Off hand and uncertain; BUT:
Isn't the large nut a special locking nut which we over here referred to as 'nylock'?
Those special locking nuts should NEVER be subjected to air tools, as the speed causes the locking material to heat up and deform....
At the moment I think you may merely need to replace that nut as that is reason for the difficulty in coming off and going back on and that your shaft is probably fine.....
Without a lot of research, this my guess of the moment.
Freedom is not something you are given. Its something you take.

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octaman
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Re: Overtorquing the swing arm

Post by octaman » Tue Mar 27, 2018 9:07 am

Hi Tommy XP

Thank you for your response.

I agree, I would NEVER use air tools on my SH. However, under the circumstances I was helpless and stranded and had to move forward and get the flat tyre fixed by someone else (!).

I have read your response very carefully and, with all due respect, I feel that you are referring to the AXLE NUT at the centre of the wheel. I am referring to the two bolts.
The two bolts (with regular washers) that hold the swing arm in place.
The swing arm has three points at which it is secured; two points forward have bolts that secure on to the engine body. And one point is at the centre of the wheel that secures with a NUT (not a BOLT) - as you correctly state.

My problem with overtightening and the question on the threads, is with the two bolts, not the one nut.

I apologise if I did not make this clear from the beginning.

----

At the same time I have made note of what you say about the nut on the axle of the wheel and how an air tool can destroy its properties as it heats up because of the tightening speed. And I thank you.
On the other hand the Axle Nut that has a tightening torque of 118 Nm did not overtighten with the air tool. So that thread is spared (smile).

-----

Standing by, . . . . . .
Ride safely, feel free

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TommyXP
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Re: Overtorquing the swing arm

Post by TommyXP » Tue Mar 27, 2018 9:24 am

My mistake......I thoughtlessly jumped to easy conclusions....
I know now what you are referring to and am at a loss of idea's at the moment.
Kind of off topic but, did you use a new 'gasket' when reinstalling the exhaust pipe, as it deforms to fit and are a one time use item? I've mistakenly re-used them in the past but now know better....
Freedom is not something you are given. Its something you take.

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octaman
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Re: Overtorquing the swing arm

Post by octaman » Tue Mar 27, 2018 9:34 am

Absolutely. Yes, new gasket.
I have mistakenly re-used them in past too. Now, I also know better. (smile)

AND I made a point of tightening the joint nuts first, on the cylinder, for a snug fit, then the three mounting bolts of the exhaust pipe!

Let me know if you come up with any ideas on the main topic. I respect your wealth of knowledge.
Thanks.
Ride safely, feel free

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TommyXP
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Re: Overtorquing the swing arm

Post by TommyXP » Tue Mar 27, 2018 10:43 am

Aluminum is soooo soft. It was hard for me to become used to using a torque wrench on everything aluminum now a days.....
All I can do is imagine your scenario as if it were mine own.
IF the bolts were tightened to the point that they distorted the threads and considering the trouble of replacing the whole casing: I'd learn to live with it.....If you got it to properly tighten I wouldn't be concerned to much and just keep an eye on it.....Seems the forces 'there' would be UP and Down and not so much lateral.....
Next time you have it apart see if you get the same effect by switching bolts.....
You could, if absolutley necessary, drill and tap the two in order to except a "HeliCoil" :
http://www.repairengineering.com/helicoil.html
I've used these in the distant past and they work well.

Also consider running a special non-cutting aluminum (forming) tap into them. They won't remove any 'meat' and would reform the thread pattern. Used to use these when working aluminum all the time.
https://www.natool.com/blog/2016/07/cut ... rming-taps

Your options are limited, so co what seems best for your personal comfort and good luck.
Freedom is not something you are given. Its something you take.

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octaman
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Re: Overtorquing the swing arm

Post by octaman » Tue Mar 27, 2018 1:36 pm

Thank you for your input Tommy XP

I was considering the second option of a non-cutting aluminium tap.

Then, if all else fails, I noticed that the thread on the casing is not blind, it goes all the way through the casing. This might allow me to put a longer bolt in and add a nut on the end.

In any case, as you say, I shall probably leave it snug as it is for the moment and keep a watchfull eye on the swing arm until the next time I will need to take it apart. And I shall deal with it then.

But I want to be prepared beforehand with my options, therefore I appreciate any and all input.

Is there anyone out there that has faced the same problem with the two swing arm bolts?
Ride safely, feel free

SH125Paul
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Re: Overtorquing the swing arm

Post by SH125Paul » Wed Mar 28, 2018 2:31 am

From reading the above... My Cents (2p) worth of supportive comment....
I tend to try and do my own dismantling and reassembly for wheel n tyre (tire) changes etc - but sometimes a workshop needs must - had a rear shock mount damaged by a wheel change monkey...

Agreed, next time the swing arm section is off... clean the bolt an run a greased / coppa slipped (as recommended if you can source new replacement) bolt in and out the threaded hole (without the swing arm in the way) and see how the threads 'feel'

I, myself use a combination of torques bolts, but prefer to use a grease / coppa slip rather than dry bolts, and feel the tightness as I do em up etc. rather than risk a dry bolt seizing...

Have not used helicoil springs - but have used 'timecerts' in wheels for disk mounting hole thread issues - these are suitable for blind holes - not sure what would work best for open holes...

The fact that the holes are not blind and a suitable NyLock nut can hopefully be used on a longer bolt sounds like a plan, would save a lot of grief and cash!... hopefully no clearance issues on the far side of the engine casing...

Often find the bolts in this area are tight in and out... lots of bolt shank for road crud to accumulate...

NyLock nuts are usually the sort with a Blue Nylon insert, I think the Rear wheel nut has a thread and a sort of two metal blade edges that cover a quarter of the circumference and are opposite... prolly got a Honda Spares Name...

I'm a castellated nut wiv R Pin or split pin fan!

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octaman
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Re: Overtorquing the swing arm

Post by octaman » Thu Mar 29, 2018 12:52 am

Hi Paul,

I like your terminology; the “wheel change monkey”! (smile)
The wheel change monkey damaged my threads!

I read you loud and clear on the “grease / coppa slip”.
I sometimes put a drop of thin oil on the threads of the bolt (which is not the best way to go) but in an emergency it is better than a completely dry bolt. If I lubricate the thread I always tighten less to compensate for the lack of friction. The question is how much less? Ha!

As for the clearance issue on the far side of the casing a preliminary inspection showed that I probably can add nut on a longer bolt but I will have to look at this very closely the next time, to be sure the nut will be seated properly on the casing.

I am also a fan of pins. Thanks for the idea. Pins add extra comfort to the mind. I could slice a nut and drill a hole in a longer bolt. I would probably turn the bolt around and insert it from ‘behind’ the casing, then tighten with a nut on the outside of the casing that is immediately visible as you look at the swing arm from the right side of the scooter. Then I could add a lock nut with a split pin on top of the securing nut. Done!
Am I going too far? (smile) I guess it doesn’t hurt.
Ride safely, feel free

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Mikey
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Re: Overtorquing the swing arm

Post by Mikey » Thu Mar 29, 2018 7:36 am

I only changed my tires once on the SH150. I removed the front and rear wheels myself. Very easy on this scooter. Purchased my tires on line. Took them to a scooter shop. When I got home they had put the front tire on the rear wheel and the rear tire on the front. Took them back and waited this time to make sure it was right. This time the front was put on backwards with the arrows going the wrong way. True story.

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