Thanks guys.
It is often the quirky things that catch us out, which is why these forums are invaluable. Like when after the rebuild I had very little oil flow. Until someone on this site suggested I enlarged the gasket holes. Why? The pump was in great order, and the new gasket lined up with c’case and pump. I followed the advice, enlarged the holes and eureka – oil flow was superb. Weird.
Same with this latest problem. Bike had been standing for months and so I drained the sump before starting. About a cupful. Started up and had to get out of the garage pdq. Never seen smoke like it. Better than a smoke grenade. And the oil leakage!!! An egg cupful every couple of seconds. Spent half an hour mopping up the mess. I have other bikes (B31 & M21 with vee twin engine) which wet-sump if left standing. However, if I run them without draining they smoke, but no more than a two-stroke. And they don’t chuck out oil. So what was going on here? Another A series quirk.
Berger’s reply was the answer. I took the drain plug out again and got about a quart. Why didn’t it come out the first time? And why such chaos just because it’s wet-sumped? These A series certainly have some idiosyncrasies. Now runs without smoke or oil loss once more.
I have over 50yrs experience in engine rebuilding, modification and design, but this bike has been hassle all the way, so guess I start out in a bad frame of mind. Bought it for the frame about 30 yrs ago, but decided not to break it as it was complete. Then last year thought I’d better get around to rebuilding it before I was too old to do so. Frame downtube was cracked so I repaired that and fitted new lugs for the centre stand. Mudguard brackets were all butchered to fit a mis-aligned mudguard. Engine cases weren’t a pair so I had to machine them and line-bore the cam bushes. Crankshaft drive-side bearing had been staked to create a press fit. Arrggh. I rebored the cylinders only to find the bores weren’t perpendicular to the face and had to bore another .020” to clean up. Head needed valve seat inserts, but no-one seemed to know valve seat depth, so I had to calculate that from valve stem protrusion. Gearbox: layshaft was bent and worn. I straightened the shaft and ground the bearing, making an U/S bush to suit. Re-assembled with selector marks in line but couldn’t get gears. Re-assembled selector with marks out of line and all is fine. Then there’s the exhaust pipes. If they were 2” longer (and silencers 2” shorter) then the bend would clear the footrest instead of being jammed against it. A bundle of aggro all the way.
I’ve had James ML, BSA A7, Velocette Mac, Triton, Hagon japanese and others. I currently have a BSA B31 hill-climb bike, Weslake speedway engined sprint bike, DOT scrambles with Villiers 6E, dog-ear japanese in a B31 frame, Honda Firestorm, my own 800cc vee-twin in a BSA M21 frame and this A10 GF. Which has been more trouble than all the other bikes. Am currently fitting an own 1,000cc vee-twin in an A10 frame.