Blown head gaskets on 1957 sporty?

[speed_bump57]

i keep blowning head gaskets on my 57 sporty, what would be causen the probblem?

[hmmmnz]

side valve?? or ohv?

edit: first of the ohv harleys :D
well i see that its running a relatively low compression ratio of 7.5:1
you havnt done any previous head work have you??

if not, then i can only guess that may be carbon build up has increased compression and thats done it, (i doubt that though) or the gaskets were faulty, or may be when they were torqued up the last time the head was apart they wern't done up tightly enough, or they were done up unevenly, have more pressure on one side of the gasket than the other,
or my final guess is that your head isn't completly flat or is slightly warped.

you might be better off asking on a dedicated harley forum,
good luck

[FJRider]

what octane levels in '57, as opposed to your normal fill now...???

[Subike]

try two head gaskets,
lower the compresssion
bad side effect>>>>> bike is slower than normal with loss of power
good side effect>>>>no tickets cause it looks cool, but cant reach the speed limit
Bad side effect>>>>>Noobs on 250's waste you at the lights
Good side effect>>>>your perfectly waxed walrus mostach stays straight.

[Brian d marge]

can u give a bit more history about the bike , has /is it stock , assuming stock the warped head ,,, or loose head .. a more hardly type will know


Rear cylinder ????

Stephen

[pete376403]

Are they solid copper headgaskets or composition? If solid copper, you could try annealing them before use (heat gasket to cherry red, drop into cold water) this will soften them.
Are you torquing the head bolts in stages to the correct figure, in the pattern recommended? Both surfaces clean, no gasket poop of any sort?

These engines are cast iron heads and barrels, correct?

[popelli]

try this website you will have more luck loads of knowledgable people and they have a dedicated tech section for pre evo harleys

http://www.harley-davidson-riders.org.uk/

or try this US based website

http://www.jockeyjournal.com/forum/

In short if your heads and barrels are straight and true use quality name brand gaskets and you should have no problems

forget torque wrenches, do the heads up as tight as you ***king can