Sym 125cc - Tightening Torque question By gingel (Read 756 times)

[gingel]

Hello,

I also asked this in the neighbor forum, but i thought i'll also ask here.
I am at the end of a rebuild, and i installed the crankshaft on the left case, and put the right case
on top of it.
There are 2 M6 bolts that are for the right case,
and the manual said to torque them to 1.5-2.0 kgf-m (around 15-20 Nm).

Well, i torque it to 15Nm, and one of them started to break, and the other was also on his way to break.

Luckily i was able to pull them out and the threads inside the case are ok.

Is it too strong for an M6 bolt?
I found a chart which says that M6 bolt in aluminum needs around 5 ft/lb (around 7Nm).

What do you think is the correct torque for the M6 bolts?

There are also the 2 M6 bolts on the left side of the engine head (where the timing).
What is the correct torque for them?
The manual is saying 1.0-1.4 kgf-m (around 10-14 Nm). Is it too much?

Thank you for any help.

[cyborg]

8nm,,,is recommened for clean and medium machine oil lubed 6mm bolt in aluminum,,,don't go loco with the lube,,,just get all the surfaces oiled LIGHTLY,,,the problem here is you were doing it dry,,,luckily you didn't pull the threads out of the case,,,thank goodness its a Sym,,if it was a chinese scoot you'd be doing inserts right about now

[gingel]

Thank you for the answer.
It is lucky that the threads are still ok.

Are you sure about putting oil on these bolts?
In the manuals of several scooters, the only bolts they are saying to put oil on,
are the 4 nuts for the head, and the 2 M6 bolts on the left side of the head.

[cyborg]

Light oiling is recommended for correct torque application

[gingel]

Thank you.

I hope the rest of the rebuild will be ok. :-)

[cyborg]

Take your time you will be fine