N15 oil problem

Hi , I recently aquired a 67 N15 , it's in beautiful condition and its engine rebuilt . after a 10 mile run yesterday I noticed oil was streaming out of the cap of the oil tank. the tank has been fitted with an anti drain valve ( I've checked and it works ) the valve was on . As I was riding I noticed engine rattle was increasing. also when warm it is very hard to kick over, even a strong kick produces no momentum in the engine. completely the opposite of when cold. I hope you wise people can help. Phil

Maybe the valve was on when the bike was sitting so the oil tank contents drained into the sump, then the oil tank was topped up and you end up with too much oil in total. When the engine then runs the sump is drained and returned to an already full tank and has only one place to go.

Engine noise does increase on a warm engine but also on a worn, so its a matter of degree, what experience do you have of Brit bikes, is there an experienced local who could check ?

On the kick resistance, this is low on a cold engine especially one not yet run in, as it beds in it will get harder to kick over as the rings seal and there be less of a difference cold to hot.

Drain the sump, get the oil level right in the oil tank and try again.

First check the oil pipes are connected the right way round just in case.

Beautifully, rebuilt and just sold and bought are red flags to me, the economics of trying to make money from restorations mean the temptation to cut corners is too much for some.

I would get someone used to Norton Twins to look it over.

When first bought my 850 in '77 I'd never owned an English. Well tank was low after left sitting for a year by PO, so I topped it off prior to starting. It caught on the fourth kick or so & oil went everywhere after a few seconds.
There I was thinking the guy had been running the bike low on oil & I was praying it had no motor damage. The rest is history. YMMV.

Thank you, it looks like you have got it in one. I have removed over 1 pint of oil to achieve a level below the top fill mark. I have also noticed that the return feed pumps directly up onto the cap which is bound to leak. I have doubled the thickness of the cork seal in hope. I think I will also remove the stop valve from under the tank as the chances of me remembering to turn it on and off are slim. regards Phil