Intruders-Alert

Can anyone confirm that they successfully used the service manual's torque specs for the head bolts on a Suzuki Intruder 1400?
It says 29 ft/lbs, but that seems way too low. I am replacing the head gasket due to an oil leak, I sure don't want to have the same problem after I am done because the head bolts weren't tight enough.

Thanks for any help

I used them and haven't had a leak.

I did tighten them to half a lb under the max, both the long bolts and the 2 studs with the nuts on them. Be careful of the 2 long cover bolts, if you tighten them to head bolt specs, you will break them.

Make sure you account for the accuracy of your wrench; if it is rated +/-0.5 lb-ft, Herb's recommendation is spot on.

The 2 values given for torque are for dry and lubricated. The higher value is for dry.
Here is a handy chart to download:



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Edit: The size of the bolt is the diameter of the shank, NOT the size of spanner or socket.

Note that the chart is the MAX torque for each fastener; the limit recommended by Suzuki takes into account the strength of the material the bolt is threaded into, and how much compression the gaskets can tolerate before failure. Over-tightening head bolts can lead to just the kind of failures corkman was repairing.

Torque of a fastener is dependent on a number of factors, The diameter of the threaded section, thread pitch, depth of thread engagement, tensile strength of the fastener and as you say, the material being fastened. 4.8 is the normal fastener for low yield materials rising to 12.9 for high yield high stress materials. you most certainly would not fit a fastener of 8.8 or higher to an aluminium base and use the torque setting recommended for this. How many times have you read that Suzuki use cheap and nasty low yield fasteners that twist off if over torqued. The truth is that Suzuki uses the correct yield fastener for the application. As for gaskets, when I replaced a cylinder head and torqued up to spec's the machine would be put into service and after 24 hours running a re-torque would be carried out when the engine was cold. Not so practical on bikes so normally I would torque to specs and leave for 24-48 hours to allow the gaskets to compress then re-check before final assembly.

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