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By Reynard24
My recently acquired 1955 500 twin has failed on its inaugural run with a loss of compression followed by a noisy ride home, once I got it started. Consequent Investigation reveals a blown head gasket on the drive side cylinder.
I’ve ordered new gaskets from our hosts but I’ve never used the sandwich type before and would like to ask what is the best way to stop it blowing again. The two nuts that are between the fins are rounded off (so much for the PO being a retired engineer!) and again I have sourced new ones but with no torque settings and no way to apply a torque wrench, what is the procedure for tightening them? I’m assuming it’s best to use a diagonal sequence but what happens after the initial tightening?
On other marques I tighten to the specified torque and run the bike up to temperature then allow to fully cool before slacking the nuts 1/4 turn and then retorquing. I then ride the bike for ten miles and repeat the procedure, then a further 50 miles followed by retorquing and finally 250 miles and repeating. This has always proved effective with composite and copper gaskets - is this valid for the copper sheet/fibre/copper sheet type albeit that I have no torque ratings. Should I use Wellseal on this type?

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