Thanks for that Kieth , I have looked at that in the past and thought it would be difficult to seal that pipe at the cam cover end with any certainty as hot oil is very viscous. Also what about the leak path behind the half time pinion via the timing side main bearing is this not a problem , and are you happy with the mod.
I have never been a fan of feeding the rockers off the return , it seems to me a easy way to avoid over oiling of the guides but at the expense of a decent flow down the push rods and onto the cam if it can get past the followers anyway. I am looking at a metered flow off the return via a drilling in the cam chest near the breather and running a small bore pipe behind the inlet follower ( forked variety ) across to the top of the cam lobe where a drip feed would drop onto the cam. Yeh I know I should get out more. All good fun.
In all the years I have run Ariels both on the road and racing it has always been the return pump failing that tests your patience. In the end I carried 2 spare pumps , I was riding long distances , I even reco'd my pumps with hard chrome plungers the lot, still not 100% reliable. In the end I rigged up a visual indicator on the handle bars ( a gutted oil gauge) which told me that the return pump was working . This saved me running out of oil as I had a large bore breather which passed all the oil out of the motor without the usual tell tale of a slowing motor as it filled up. Sorry for being long winded. Regards John.