Forum

[Martin]

Colin, forgot to mention I had the PVC
valves tucked up parallel to the c/case
with 90 brass elbows. Currently they should
blow out as the pistons come down, but should
I have one reversed for air to come in?
Since the 'bike is a mis-match, these don't
look too untoward as they only about 1 1/2"
long, put plastic tubes leading to the rear
chain, (and tyre!)

[Mark M]

Gordon, I think I'd remove any restrictions on the breathers while you sort this out. Enfield twins are notorious for very slow pressurisation of the oil system, it takes an age to get a return at the oil tank. I usually prime the engine with a few minutes kicking every time I pass the bike for weeks before I try and start it!
REgards, Mark

[Norm]

Gordon, when you assemble the pumps you must give everything plenty of oil, in the pistons, anywhere you can squirt oil because you can also get airlocks in the pumps and they can be hard to shift. Why are you getting oil on the floor, where is that coming from?

[Colin F]

Gordon,sounds like you need to backflush those galleries that are at the front of the timing case side,to make sure oil is flowing freely TOO the scavenge pump.You should be getting more than a "intermittent dribble"that is no air involved when the sump is half full of oil.Mine gives a solid flow when first started after a layup.Check that the disc is sitting flat in the pump,i had problems that eventually i solved when i discovered the pump crankpin was bent slightly which made the disc oscillate and lift off the base which let it suck air.I could see the uneven wear which was the giveaway.
Also check the timing cover gasket as any leak there and they will suck air before drawing it up from the sump,absolutely terrible design but careful fitting and all will be ok.
Sounds like you have 2 PVC valves,i would go with one,seriously there's not much to flow through them,on my original one
the flow is through the crank flapper then out a 1/4" pipe that comes out the bottom of the primary case,they have no problem copping with reasonable rally speeds.

[Martin]

Mark, am sure filler cap was off etc whilst I was
sorting thee motor, and endless kicking. This time
had primed everything like Norm has just suggested
with a squirt oil can rammed in every orifice, so
when it finally had dribble return, was consoled
with that. NORM, primed it all adequetly as just
mentioned. The oil on the floor had poured out the
exposed main bearing as the outer primary chain
case was left off with all the sundry timing checking.
COLIN. Have blown out the accessible airways with
air line with timing cover off and on, and also the
same with the spare later c/case to figure out where
the oil actually goes around. Previously lapped the
oil pump, and checked throughly, also have the correct
early timing case cover in place so oil holes aline
with new gasket each time. Will utilize the 4 screws
you spoke of to confirm the return flow. Good you
mentioned your bent oil pump spindle end crank as
isues like that can play havoc. Once again, unsure
why I didn't use the original c/shaft with end breather,
maybe one of the journals had been once ground under
size, and I never had the conrod to match. Will go over
next week and fiddle further! THe origin early motors
must have run OK 9'cept for the head gasket oil leaks)
as think I read a road tst of someone going for holiday
over the Alps on one, hopely on our machine, and not
another marque!

[Colin F]

Hi Gordon,there was an article done especially on the head gasket oil leaks on these early Twins,
i think it was "Motorcycle mechanics" magazine(1960'-70's?),basically it entails alloy tubes being inserted in each
barrel-head oil gallery and a tight O ring over that with the gasket sized to suit.I haven't tried it
as it sounds a bit hit and miss to expect the holes to line up.

[Martin]

Actually, Colin, had discarded the original c/heads,
a friend used them to display 'biker's wallets in his
cafe! Have installed 'Tomahawk' c/heads from about '57,
and fabricated the external oil lines up to the rockers
with 3/16" copper pipe and brass fittings. Looks pretty
but may be incorrect.

[Colin F]

Gordon that's exactly what i'm doing on this rebuild,sandcast crankcases and external oil line heads,cheers
colin

[Norm]

Gordon,
I would get the primary case machined to take a seal and you can bolt it on and run it without fear of any rubbich getting back in through the bearing and no oil being thrown around. This is just for starters. My main concern is not so much the wet sumping, but is there feed oil going to the big ends

[Martin]

Norm, will conside that practical primary case
seal update when I've sorted the other issues.
Though I think the sprocket splines on the later
alteranator c/shaft don't have a machibned spot
for a seal ruubber to lap on. will look art it
when I go over to the garage next week again.