Head problem

Evening gents.

I´m working on my late fathers 750. It used way too much oil, so I took the head and cylinder off. Have fitted it with new rings, valves, guides, composite head gasket from Andover ect. Bike started first kick and sounded fantastic, I let it run for a few mins, just to worm up a bit. Then cool down and re-torqued the cylinder and head according to workshop manual. Took it for a 5 km ride, left it to cool down then re-torqued again. Now I´ve just bin out for a ride, did 40 miles/60km and the oil is P*****g out between cylinder and head. It´s probably no more the 15 degree celsius, the oiltank was full when I left. Only did small roads with lots of changing up and down, no A road or highway. Was planning to re-torque tomorrow morning to go for a 100miles run, but it looks like I´ll have to remove the head again.
Problem is that the bike is with my mum here in Denmark and I´m living in the Netherlands 400miles/600km away, I was hoping to get it ready for next time I´ll be in DK, when I´ve planned a weekend away with a friend.
I did the same running in with my own MK3 and it´s okay, should I run a 750 in differently or am I missing something here???

Thanks, Dan.

There's nothing wrong with your running in technique. There must be a problem with the head gasket or maybe a warped head, maybe something else. What kind of gasket did you use? Did you use any sealant? The head has to come off again and that should give a cue as to what the problem is.

A flat glass plate, a sheet of 600 grit sandpaper will tell you if the head needs a cut. Machinist’s dye and a flat head will tell you the condition of the cylinder surface. If you are using a composite gasket, no sealant should be needed. Some do recommend a thread placed around each pushrod tunnel. A wisp of oil on the head and cylinder mating surfaces will do. You must make sure ALL head fasteners threads are clean and true. Best to chase with a tap and die. Remember, torque readings are only a measurement of resistance to turning, not clamping force.

You didn't say how many miles were on the motor before rebuild, but new rings without new pistons is risky. The rings wear out the the "lands" of the pistons and new rings seldom seal properly with old pistons.
Also, I never fill my oil tank, and keep the level very near to the "add" mark on the stick.

I have a head problem, to many beers last night lol, your head could need a shave but once you take the head off again you will see where the oil will be leaking from, could be the PR tunnels from a stud could be a few things but you get a better picture when you pull the head and look at it closer, oil will leave a trail where it comes from, how much is coming out I think you said pissing it out, anyway good luck with it.

Ashley

Morning.
Thanks for your replies. I used a composite gasket from Andover, with no sealent. The bike was dry before I took it apart, so I didn´t check if the head was warped, I probably should have.
Bike has according to my father done 260,000km, but have bin rebuild a couple of times, not sure how many miles since last rebuild, but can´t be more then 50,000. Pistons and bore were good, so it was actually a waste of time to take them off, but I thought better to be safe then sorry. When I took the head apart, I found that the right rockerarm spindle had ben moving around and probably overfilled the head, that coursed it to use oil. I have shimed the rockerspindles out to be flush with the head and fitted new alloy spildle plate.
Right, a quick breakfast and I´m off to the workshop. I´ll start with re.torquing the head, just to see how much is needed. I´ll let you know how I get on.

Thanks, Dan.

Good afternoon Gents

I panicked a little too early yesterday, my apologies. After I posted my message this morning, I read this thread: https://www.accessnorton.com/NortonCommando/oil-drip-between-cylinder-fins.25124/ and I decided to investigate a little further. I re-torqued everything, cleaned everything and borrowed my mums foot powder. After a 5km ride, the leak was clear, the inlet valve cover nut. Fitted a copper washer under the nut and took it for another 5km ride and it was dry. Turned out it could leak down from the nut, between the inletmanifold and then the oil would come out at the front of the head. I´ve had leakes from the rocker spindles and banjoes, so had checked that, but never from the inlet valve cover. I´ve heard about the foot powder before, but haven´t used it my self, if I ever (when ever) get a leak again I´ll use it.
Did 100km this morning, let it cool down, re-torqued it and now just back from another 80km. Another ride tomorrow and it´ll be time for another re-torque.
Thanks again for your help. It´s great to be out on my dads Norton, it´s a great way to honor him.

Dan

Glad to hear it well done mate, that's a whole lot better than pulling the head off again!!

You can over torue the head gasket, when I do a head on my Norton I torque it down then do a few miles and if no leak then just ride for a few hundred ks then retorque it but then I use a copper head gasket, my head only gets the one retorque I have been doing this way every time the head is taken off but thats only been 4 times in 43 years or riding it and the same with a few other Norton motors I have done over the years.
Like you have found its little things that can cause oil leaks and not the head gasket itself another place to look as well is the front studs that the valve covers sit on can also leak.

Anyway glad it was a simple fix.

Ashley

The front rocker cover gaskets have a lot of excess material on the inside. This can form a dam and trap oil. I use gasket cement to attach the gasket to the rocker cover then on the bottom half of the cover trim away the excess inner gasket material with an exacto knife to match the cover edge. Smear of grease on the other side of the gasket and it should come away cleanly to reset tappets.
As Ashman says a copper head gasket should need only one retorque after startup. However, a composition head gasket(type with the steel ring around the cylinder in gasket material) require more retorques. They seem to take longer to settle in. My break in is start the engine and run stationary for about 5 minutes or so until thoroughly warmed up. Keep the rpms fluctuating between 2-3000 and don't let it idle. After cool down, torque head and set tappets. Start riding, use a lot of mid range rpm's 3-4000 rpm, no lugging ,no steady throttle. After 100 miles it's change oil and filter, torque head and set tappets. More riding, giving it some higher revs. After 500 miles another oil and filter change, another torque and tappet set. I use the same Valvoline 20/50 dino Motorcycle oil for break in and general use.
Should be good to go at this point.

Gents. Thanks Again for your help and advise. I managed to do a total of 500km on the 750 this weekend and it´s dry. Took it for a 80km ride this morning with my mum as passenger, she use to ride with my father so she enjoyed it. I´ll be in DK begin june, then there´s a long weekend of riding planned with my friend on his Triumph TR7.

Dan