I continue to be plagued by oil leaks on both my Armac Cub and my old 'bitza' Cub.  Most of the oil seems to leak around the rocker covers and push rod tube.

Both bikes have had various mods done to the breather system.  My Armac Cub has a 230cc conversion and modern piston but I now thinking about fitting that to my old Cub and fitting a Max Heys 250cc barrel conversion to the Armac which I believe uses a modified oil return.

I'm aware this mod returns the oil from the rocker area down the barrel studs rather than down the 2 small holes in the top of the barrel.  I'm wondering if will help with my problem as I think this area is flooding with my current set up.

Does anyone have any more information on this mod?

As usual, any help appreciated. 

My Ariel used to leak from the rocker covers after a days hard use, I cured it completely by adding large vent pipes to both rocker cover caps. These run vertically up under the tank and have a small gauze filter on the ends to stop muck being pulled in.

The engine was just not vented enough or it has a bit of blow-by, either way the venting cured the weeping problem.

Edited August 6, 20188 yr by collyolly
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12 hours ago, brucey said:

I continue to be plagued by oil leaks on both my Armac Cub and my old 'bitza' Cub.  Most of the oil seems to leak around the rocker covers and push rod tube.

Both bikes have had various mods done to the breather system.  My Armac Cub has a 230cc conversion and modern piston but I now thinking about fitting that to my old Cub and fitting a Max Heys 250cc barrel conversion to the Armac which I believe uses a modified oil return.

I'm aware this mod returns the oil from the rocker area down the barrel studs rather than down the 2 small holes in the top of the barrel.  I'm wondering if will help with my problem as I think this area is flooding with my current set up.

Does anyone have any more information on this mod?

As usual, any help appreciated. 

Brucey my Cub also has the engine oil in frame which means the oil return pipe exits near the top yoke, therefore higher than the rocker feed. Might this cause the oil especially when hot and thinner to take the path of least resistance via the smaller diameter pipe to the rocker boxes. I do not know if this is the case but if a side oil tank were used is the return then at a similar height to the top of the engine causing less pressure to be needed to pump back?

Edited August 6, 20188 yr by trialsrfun

I run a standard  200 cub and looking to upgrade to 230 Mine is fitted with  SM oil tank under the fuel tank using the large bore rocker feed pipe  The original type is much smaller bore I take it the oil is not draining away from the head As the studs are sealed with the barrel base gasket so some type of draining is required from the rocker box to the stud and from the studs to crank case  If not the oil will fill up till and try to drain down the push rod tube I also fitted an ARMAC breather to the crank case where the distributor was fitted 

Thanks for the replies guys.  I'm going to strip my old engine to find the cause of the sudden excessive smoking and oil leaks.

My Armac Cub has a standard oil return set up with the Armac crank case breather and every other mod I can think of to eliminate oil leaks!  I am using a large bore rocker feed pipe.

I'm just in the process of justifying a 250 Max Heys barrel conversion with the associated oil return mod to see if I can resolve this problem once and for all!

On ‎07‎/‎08‎/‎2018 at 12:11 PM, brucey said:

Thanks for the replies guys.  I'm going to strip my old engine to find the cause of the sudden excessive smoking and oil leaks.

My Armac Cub has a standard oil return set up with the Armac crank case breather and every other mod I can think of to eliminate oil leaks!  I am using a large bore rocker feed pipe.

I'm just in the process of justifying a 250 Max Heys barrel conversion with the associated oil return mod to see if I can resolve this problem once and for all!

Would be very interested to learn of your findings Brucey.