top end gasket set recomendations

[davidcumbria]

This might help you a bit. I fitted the the 2.5 mm thick 90 hardness rings after reading this and they've been fine

https://www.sohc.co.uk/index.php/topic,28673.0.html

[neat street]

Thank you Dave, this has helped alot :-)

[paulbaker1954]

I went through a nightmare around DS aftermarket gasket set tring to fix an oil leak.

 I ended up using the aftermarket O rings along with a proper Honda OEM gasket plus having head skimmed.

As many have said the relative thickness of head gasket and O rings is critical to getting a oil tight seal.

[Bryanj]

Its not the head you need to skim but the barrel so as to reduce the depth of the recess for O ring by 3 to 5 thou.
I did once think aboutputting a small shim in the recess but getting an accurate sized shim that thin did not appear easy

[Robert W]

I always used a light film of GE Silicone (pure Silcone caulk, not the paintable goop) on the head gasket and the O-rings for the oil passage. It was a poor design relying on the O-ring alone between the head and the cylinders. Why they didn't have a similar setup for the cylinder to crank case with the oil jet is a mystery. However I've got Yoshimura big bore kits with higher compression pistons in both my CB500's and they never leak at the cylinders or the oil passage. You have about a half hour before it starts to set too much so make sure you get the head on and torqued within that period. The silicone also makes for an easier cleanup the next time you change the gasket. Paint thinner or mineral spirits seems to slowly eat the film left behind.

[Bryanj]

Not a favourite of silicone, just a tad tpp much can block the oilways. When using original Honda top sets we never had a problem till asbestos was removed from the fibre material