I have a 96 heritage, I bought it with a head gasket leak so I pulled it down and went ahead and replaced all gaskets .....i happen to notice 2 grooves machined into the cylinder heads, nobody seems to no why they are there? I called my machine shop buddy and he said they sound like they were put there for compression release .......ANYBODY HEARD OR DONE THIS B4? THANKS

 

Can you describe the grooves? Are they circular around the cylinder? May have been machined for o-ring head gaskets at some point.

 

They are vertical and start about 1" from bottom and stop 1" from top of cylinder wall....they are about 3/4" apart from each other too.....they deff are machined in there.......the bike has high dome pistons too...

 

Wow, weird. Out of my league. Personally, I'd go w/ a new matched set of jugs n slugs.