Redid the top end on my 1984 flh in march, put on about 800 miles and front head gasket blew. Any causes I should look for before replacing gasket ?

 

a little more info helps-------- but you need to know if the head bolts bottomed before it was actually tight, rust in the threads does that did you send a bottoming tap into the bolt holes in the heads - glass beading media in the bolt holes does that - milling the heads more than once / did you buy the bike new - and using a china copy of a real head gasket like a .040 cometic will do that -- what is it you actually have

 

All that and, if it blew before it may have flame cut the aluminum of the head at the gasket surface..seen it more than once. You won't seal it till the gasket surface is repaired...Otherwise it will blow out [in the same place] everytime.

 

Had this bike for 8 yrs. with no major work. Threads were clean but did not run tap through. Used a james gasket. Upon removal the whole side that blew was blackened and the other side clean. Saw in another post your advise on cometic gasket, will be using one of those.

 

i only use cometic today in my shop for the harleys nothing else, they also make the base gaskets in tin and the shovel rocker box gaskets and in the years i am using those i have not had a leak

 

Should I replace base gasket also ?

 

if its 1920s paper type - its 4 nuts and a ring re fit - i know what would happen in my shop - both would be off and all of it replaced -- we are talking a couple of hours and the correct gaskets -