Torque and gasket replacement

[frankieboy]

Hi everyone,
as I am a newbie, I have another simple question.
The numbers written on the top of the hex machine screws (mostly 8) means the torque in NM?
I'm I right that you have to put new gaskets onwhen opening the cylinder head top an the wasserpocket top. Both are leaking a bit after reinstalling with the 15 year old gaskets?
Thanks in advance.
Frank

[fairdeal]

sorry, those markings indicate the tensile strength of the bolts:

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Typically, gaskets are not re-useable.

The Service Manual indicates when that is the case;

it also provides the required installation torque for each bolt

and in some cases,

that the tightening should be done in steps, and the bolts in a specific pattern / sequence

[cpostis]

Frankieboy,
This is for your F50AET?

If so, Service manual that covers your engine is Yamaha part 3 LIT-18616-02-33.

Here's a link to purchase.

LIT-18616-02-33 YAMAHA F50Z-B T50Z-B (F60A-

Here's AN EXCERPT ATTACHED.

[zenoahphobic]

sorry, those markings indicate the tensile strength of the bolts:

image hosting site no sign up

Typically, gaskets are not re-useable.

The Service Manual indicates when that is the case;

it also provides the required installation torque for each bolt

and in some cases,

that the tightening should be done in steps, and the bolts in a specific pattern / sequence

Where does the OP's "8" sit on this table?

[pstephens46]

Where does the OP's "8" sit on this table?

Good point

[fairdeal]

That IS a good point!

I've never paid attention to the heads of the bolts on my F225 (why would I)

but it looks like some - by no means all -

M6 bolts have a "6"
M8 bolts have an "8"






Yesterday, I changed the starter motor on a Honda Accord

here's the head of that mounting bolt; must have been M12
totally inscrutable marking...

[zenoahphobic]

I must admit I have been amused at why the number tells me what I thought was the thread size. But it didn't help me select the correct spanner, the head size has another number system.

[pstephens46]

Is that a Yamaha diagram?

[boscoe99]

I must admit I have been amused at why the number tells me what I thought was the thread size. But it didn't help me select the correct spanner, the head size has another number system.

The number denotes the shank diameter. In mm.

A different number denotes the wrench size for the bolt head.

[frankieboy]

Now it's clear to me, thanks for the Info.

[cpostis]

Attached are torque specs from a manual for F50AET (I believe this is the motor your speaking of?).

Always use the "Specified torques" over "General torques" if it is listed in the "Specified torques".

Please print and/or save as I will probably remove from the forum site limited space storage within a week.