Oil catch tank pumping

Problem with my race bike. The catch tank is spitting out oil under pressure & coating the bottom of the petrol tank & seat as well as inside the fairing etc.
It has the standard breather above the drive case a small brether pipe from the timing cover & the oil tank vent all feeding into the catch tank.
Engine was wipped out & honed new rings fitted & guide seals replaced.
I though this was going to sort it. No smoke from the exhaust engine runs well.
Two suggestions.
One run 3 ltrs of oil (the tank holds 7 pints & I have put in 4 1/2 pints)
Two the pressure relief chamber is blocked resulting in the oil being pumped straight into the catch tank?
It was also suggested that I run the breather pipe into the oil tank.
I have looked up the info on the site & after I have looked at the pressure relief valve I think a check valve seems to be the first item I shouls fit.
Anyone other suggestions?
Thanks Chris
750 Atlas motor at the moment

Chris
Normally I'd say fit a non return valve in breather at any cost because they work, but if you have the cam breather and the disc parts still fitted I'm not sure if there'd be a clash of personalities between the two parts. With a large bore pipe (only possible on 73 on and modified engines) from the timing case you shouldn't need a rocker box breather with a valve.
Don't know what oil tank you have but you could no worse than run the breather a la Commando into the tank and vent the tank to a catch bottle. It has to be the best way. Ok I don't race mine but with very hard road use I have no problems with the non return system, 1/2" pipe from timing case to tank, 3/8" tank to catch bottle. Engine is dry as the proverbial bone.
I'd say go for it, Norvil do the valve and small fittings for cam breather but really any PCV valve will do for a test. If you reroute yr breather to tank and run the engine you should notice heavy breathing for a few seconds after starting which the subsides as crankcase pressure equalises. You probably won't have negative or zero case pressure but it will reduce significantly, all depends how much blowby there is.

Motormite/HELP 80190 check valve

Thanks Keith

My oil tank only has the one breather pipe so I dont want to weld in another.

I will have a word with Les ie his valve.
Any idea where I can get a Motormite/HELP 80190 check valve?

Thanks all the best Chris

Chris
Not seen the Motormite over here. It is a neat little unit whereas the Norvil is actually a big old lump of brass intended for Marine use. Someone found the real UK source a while back but I don't have the site.
Even if you can't get another breather into the tank it will substantially reduce case pressures. Just think about the air volume those pistons suck in on each stroke, there's nowhere for it to go and with some blowby you'll always have a pressurised crankcase and head. If you can get the air out and stop any getting back in it's more than a start. Some talk of negative pressure being damaging but I don't think you'd ever get that situation as long as ring sealing isn't perfect. Not unless you carry out the dry ring breakin and harsh running in promoted by a US engine builder. Again there was a thread here a few weeks ago on that....but can't find it.

Here's the special running in process, seemed to work for Scim.
http://www.mototuneusa.com/break_in_secrets.htm

I fitted the Norvil non-return valve - as stated previously it is a bit of a big bugger but it does seem to work. If you go that way be sure to check that the valve is OK on arrival. When I received mine I tried to blow through it with no success - I gently poked a screwdriver into the valve - there was a slight 'click' and the valve then freed-up. You should be able to easily blow the valve open with normal 'lung-pressure'. If I'd fitted it without first checking it I suspect I'd have blown every seal in the engine !

Thanks

Thanks Keith & Mark
John Conroy runs his race motor in with a wipe of oil on the rings only then runs the motor up dry! Told me off for oiling the bores! Learnt a lot in 20minutes. His motor revs to 8
I will post a new message for the Dawson valves to see if anyone has a source in the uk.
Might get out at Aintree if not it will be Brands.
Thanks again
all the best Chris