Motor mounting bolts

[Scott5297]

Really helpful info. Thanks
I’m going to need a bigger torque wrench. My current one is 1/4 inch drive and only goes up to 24nm. I’ll get a bigger one and give those bolts another go. I used Allen keys last time so no wonder I couldn’t tighten them. Seemed rock solid with an Allen key.

I did remove both cranks and greased the threads but probably did not tighten up anywhere near 50nm. In Halfords I’ve see a 3/8 inch torque wrench for about £85. I think I’ll try that as it has a torque range of 12-60nm

The things I have include:
https://www.screwfix.com/p/magnusson-torque-wrench-1-2-x-18/6879v?_requestid=815550


https://www.screwfix.com/p/magnusson-1-2-drive-hex-bit-socket-rail-6-pieces/5207v


Along with a mini torque wrench and some hex bits I have most bases covered.

The purists might argue against greasing the threads as you can over tighten them. And, being greased, they will probably become loose again. I turned to Loctite because the crank arm bolts became loose on their own.

Good luck!

 

[Beekeeper]

Ok so I’m gradually narrowing down the cause of the dreaded creak. One day, just one day maybe I will be free of my creaking nemesis

This time I really did tighten up the crank bolts very tightly but it made no difference. No difference with seat in or out. No difference if headset loose or tight, no difference when when I swap pedals,

but.......

If I hold the top tube as shown and press hard down on the left pedal I get the creak once and not again with that pedal. If I swap sides and push down on the right pedal I get the creak but not again on that side. And so on........

 

[Frankieboy]

So, it’s pointing to the motor shifting on the bolts, in my view.

 

[Beekeeper]

So, it’s pointing to the motor shifting on the bolts, in my view.

Yep it’s looking that way.

I’ll completely remove all the motor covers on both sides and then put cranks back on and see if it’s the cover actually creaking first, then I’ll have eliminated nearly everything else

 

[Beekeeper]

Progress tracking down the creak:-

Took cover off again on the left side.
Set torque wrench at 11nm and tried the 2 smaller torx 2 bolts. They were pretty tight but maybe went a little beyond 11nm until I could just see them turn ever so slightly and I stopped at that.

Then tried the 3 bigger bolts (size 6 hex key) even at 20nm they would not turn so I said to myself I’m going to take a bit of a gamble here and I set the wrench to it’s absolute max (24nm). To my amazement all 3 bolts turned ever so slightly and then the wrench clicked.

I put the crank back on and left the cover off.
Rode around the garden and tried everything I could to make the bike creak...... NO CREAK!!!

Hurray!!!!! Finally!

There still remains the possibility that the cover may have been the issue and the bike will creak when I put the cover back on but I’m almost there with my process of elimination.

Almost time for the creak to pack it’s bags and move to another town. It has haunted this one for a little too long.

 

[Beekeeper]

Cover back on and all sorted. Bike as good as new again.

Still we must never let our guard down, even in the midst of victory.
In my eagerness to test the bike out after hurriedly putting the cover back on, I started peddling furiously down the garden but didn’t get very far before I noticed something was horribly wrong.

I completely forget about reattaching the left crank arm ?

 

[TheRealPoMo]

Progress tracking down the creak:-

Took cover off again on the left side.
Set torque wrench at 11nm and tried the 2 smaller torx 2 bolts. They were pretty tight but maybe went a little beyond 11nm until I could just see them turn ever so slightly and I stopped at that.

Then tried the 3 bigger bolts (size 6 hex key) even at 20nm they would not turn so I said to myself I’m going to take a bit of a gamble here and I set the wrench to it’s absolute max (24nm). To my amazement all 3 bolts turned ever so slightly and then the wrench clicked.

I put the crank back on and left the cover off.
Rode around the garden and tried everything I could to make the bike creak...... NO CREAK!!!

Hurray!!!!! Finally!

There still remains the possibility that the cover may have been the issue and the bike will creak when I put the cover back on but I’m almost there with my process of elimination.

Almost time for the creak to pack it’s bags and move to another town. It has haunted this one for a little too long.

So Beekeeper, how has it gone ?
I wimped out on my 6mm hex socket heads and only went to 12Nm - still a little creaking.
Any issues after going to 24Nm ?
I assume your bolts look like this ?

 

[Beekeeper]

So Beekeeper, how has it gone ?
I wimped out on my 6mm hex socket heads and only went to 12Nm - still a little creaking.
Any issues after going to 24Nm ?
I assume your bolts look like this ?
View attachment 32533

Hi there,

I’ve not heard a single creak yet so problem is definitely solved.

I first tightened the small torx bolts to a touch over 11nm and then the larger hex bolts to 24nm. From my estimation, the hex bolts must have been somewhere between 20-23 before I tightened them

Not sure if it was the torx bolts or hex bolts which were the issue. It could have been both loosening slightly over time.

I guess you could always tighten the smaller torx ones first and test the bike and if there is still creaking, go back and tighten up the larger hex bolts.

 

[TheRealPoMo]

Thanks Beekeeper, I'll leave it until I feel like ripping the cover off again and go to 24 Nm.
I was a little spooked because I forgot a 6mm allen head bolt is an M8, not an M6 and M6's recommended max torque is generally well below 20 Nm.
Cheers

 

[TheRealPoMo]

I decided to dive in and remove each of the 5 bolts/screws that hold the motor and replace them with copper grease on the shaft and head and blue loctite on the thread.
Someone suggested turning the bike upside down - truly the best suggestion. Made it SO much easier than previous explorations. I haven't turned a bike upside down since they had hydraulics but no brake issues arose.
I removed each one and replaced in turn. Only thing I was concerned about is that the M8 bolts are secured on the drive side by nyloc nuts that are semi-captive - they are prevented from turning by the motor case but not secured. i was worried that with 2 of them, the frame covers where they live and if I removed the bolt, they would fall into the frame. I leaned the bike toward the non drive side at 45 degrees and carefully removed the bolts. Replaced them greased and loctited very carefully and the nuts bit without issue. (the frame may in fact prevent them from falling - I did not want to find out).
So in terms of creak, it definately made a difference. There is still something there when I really push it but at this point I realised that maybe some of us (me included) are losing perspective on this in the crusade to eliminate the creak. The chain clicks , the spokes shift, the nobbies hum - always going to be some noise. On the dirt where these things belong there's plenty of other noises. Time to forget it.