Oil b4 start up ? Where and type..

greg brillus

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The ones I did were on a series "A" barrel.......not so easy to replace as a post war one.......The oil feed holes (2 of them) were too high up, they are an unusual shape, and using 2 of countersunk rivets worked well. They can not fall out as the heads of the rivets are held inward against the mouth of the crank case........Post war ones, I generally change the assembly.......its pretty rare to find ones that are still serviceable.......Never had a head to barrel leak and any piston seizures to date.........I don't like doing things twice.
 

Matty

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Hi
On my Comet, which I have owed since 1956, I simply blanked off the oil feed to the barrel from the timing cover when I had a rebore and new low expansion piston about 20 years ago.
The bike has done at least 50,000 miles since including a lot of 70mph motorway cruising up to the Isle of Man with no problems at all.
It does around 600 miles per pint of Morris Golden Film 20/50 oil, which I think must be of much better quality than the oil the engine was designed for in about 1938 and I think this consumption is acceptable.
The only real change otherwise is to have a sealed exhaust valve guide fitted to improve the consumption from a previous 200 miles per pint.
Matty
 

Robert Watson

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Not to turn the thread sideways too far but I think you only really need a seal on an Intake valve. When the exhaust valve is open the engine is on the blow part of the suck, squish, bang, blow cycle. When the intake is open it is on the suck part off the cycle.

And just to keep close to the thread. When we did the big Europe trip in 2010 it was just over 5000 miles and about 1/2 way through I added 1/2 L of oil. I use (In North America) Valvoline VR1 20/50. There is an oil thread elsewhere here that talks of the film tests on a lot of oils by a Norton guru in Colorado and it was pretty well up on the list for running flat tappet cam followers.........
 
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Matty

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Hi Sorry all ==Must be senile decay for me because obviously it was the inlet valve guide the oil was going down !!!
Matty
 

Albervin

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I shudder when I hear people saying they get over 600 miles/pint of oil. I change oil twice a year or at 5,000 miles. Maybe a small top-up at 3,000 miles if I have been very exuberant but usually nothing.
 

Matty

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Hi
My Comet usually did about 200 miles per pint when I first bought it in 1956 and the Phil Irving hand book stated on page 95 this was the expected consumption so I have never worried about it.
This or 250 miles per pint or more was the norm even after a couple of rebores and valve guide replacements over the years, and the engine was always mechanically very reliable though it was often hard to start until I changed the plug even after a fairly hard run - but it always smoked a bit.
So a couple of years ago Conway motors fitted an oversized sealed inlet valve guide and new inlet and exhaust valve, mainly to stop the Oiling up.
I consider the problem now fixed at 600 miles or so to the pint and with little smoke and starting excellent.
I have two mags - both in excellent condition with bright spark condensers so any starting problems when hot are not the traditional hot condenser problem which I have had several times before finding the "brightspark" fix.
So how do you get 5,000 miles per pint of oil when I get 600 with my modern Vincent spares low expansion piston and 2.5 thou clearance rebore, new guides, the cylinder lubrication feed blocked and a fairly hard run in to avoid glazing?
It's a puzzle - but no problem.
Matty
 

Robert Watson

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Actually I said a pint 1/2 way thru a 5000 mile trip, so only 2500 miles per!

First thing is NO leaks, as in dry as a bone. The only indication of oil is the little puddle of milky oil at the end of the breather.
Second is to have virtually no blow by past the pistons. This by the way on an engine with 9.4:1 comp. Mk2 cams, ported heads and bits like that.. The bores are dead round and the compression rings are high quality chrome from a Honda car and well seated. (We has a small 1985 Honda civic and had to take the head of at around 350,000K kms as the gear had come adrift on the cam and I wanted make sure the valves hadn't tangled. You could still see the cross hatch in the bores and there was no discernable ridge at the top of the bores.) The pistons went in at .003 clearance and the intake guides have very effective seals. That trip was in 2010 and the engine now has around 65 or 70K on it since the last overhaul about 20 years ago, and still performs well but it does have a few weeps and does use a bit more oil these days although last year it didn't burn a drop! Mostly I think because it got zero miles on it!
 

Monkeypants

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If ever you manage to get the oil leaks sealed up then it's best to leave the engine untouched.
In fact, once things are fairly tight and dry, it's best not to look directly at the engine. If you must look, just give it a quick glance then immediately avert the eyes.
Direct eye contact with leak prone areas will bring on great gushing leakage!

Glen
 
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