Well I got the top end back together and with the top end gasket kit (cometic) there was two gaskets for the cam cover. I have an S&S bottom end btw and my bike is a bottom breather but I installed new rocker boxes and im gonna set it up for top and bottom breather. Anyways I had already bought a gasket and put the cam cover back on not aware there are two different gaskets, one that just goes around the outside of the cover and one that has a "window" in the bottom left corner. Well of course I put the wrong one on and need to pull the nose cone to replace it. Can I do this with the top end assembled? Or do I need to cut the pushrods out to get it off?

 

I have never tried it, but there is said to be a magic position where there's no load on any of the valves and you can pull the cone. It's come up here recently. One of the big wrenches mentioned it, SORRY, I FORGOT WHO, John or Spanners, I think.

 

You can do it with the top end on, you need to set the notch for the ignition cup in the end of the cam to the 5 o'clock position and make sure you push on the cam as you pull the cover off.

 

Never mind Spanners got in before I finished typing!!

 

who told you you can convert a bottom breather to a top breather by just changing the gaskets -- or did i miss something

 

Boy am I glad to hear that, thanks Spanner!

 

Not converting it John just going to use both. I changed the rocker boxes to ones with umbrella valves and removed inserts from the heads. Now just need to figure out what backing plate I need for my S&S carb or maybe switch to a different A/C setup.

 

question Y -- the bottom breather was on every motorcycle made in the USA from the 1900s to emissions was mandatory

plus think about it this way - the pistons are like 2 upside down water glasses moving downward at a hi rate of speed into a small pocket so the oil and air is blended together - then when the rotating breather valves opening come into the engine blocks window - a rush of air and oil < what does it do ??? lubes all in the cam chest and neturals the air in the oil tank so as not to loose the oil feeds prime ( oil tank to oil pump intake )
the remaining air that is trapped in the lower unit is again sent back in to the heads and it also aids in lubing the top end of the motor / then the cycle starts all over again

if i am incorrect about this i am sure someone will have a better description of how this all works

when you open a second air escape that did not come on a bottom breather or on a top breather, you create a void ( dead spot ) in the vacuum as i see it that is needed to help purg the lower units exit into the cam cover - to me this will cause the lower breather hose to spit out oil while your driving

someone else have a say in this i would like to hear it /

 

FWIW a friend of mine has both on his but either I came that way or PO modded it.
Its a thunder mountain with a 113 S&S motor.

 

being an S&S motor it might have a reed breather - that changes things