Forum

[Martin]

Finally got this very early 500 Twin
fired up after a long distributor issue.
Despite endless kicking before the ign.
was resolved, and the motor run about 10
minutes overall, not once was there a
hint of the pump returning, nor flow to
the seperate tappet lines installed on
the later heads/barrels. Have followed
Norm's guidance since on lapping in the
pump etc and will prime everything as he
suggested also. Am well aware of the oil
holes, and oil passsage discrepancies
and only used these early c/cases as they
were compatible with the only primary
chain case I have. The very early c/cases
are sand cast with the 6" filter cavern
and have no internal preesure valves. Am
sure I blew out every oilway after a
complete overhaul, soaked the ersatz 6"
filter, and even added our host's filter
sleeve. Just wondered how long does one
kick a plugless motor over before the
early low speed pump responds as don't
want to possibly damage the moter any
further, or any other tips to insure the
pump is functioning

[PeteF]

If it ran for 10 minutes without oil returning then something is amiss. I hope you oiled everything well as you reassembled it!!

[PeteF]

To be more helpful, you could try towing (or pushing) the bike in gear with the plug out. Quicker than kicking anyway.

[Colin F]

Gordon,one thing,the oil return may take 10 minutes as it has to firstly fill the oil filter cavity which is pretty large in the Sand cast motors.
Both crank feed and rocker feed should be self priming,as the pump is below the high oil level.So with the feed pump cover off oil should drain through 2 holes out of the 4,(from memory?)Now there should be 2 screws just in front of the Generator,if you remove vertical one you should be able to see oil coming from that if you squirt some oil through the rocker feed hole at the pump.If it's coming out there it should reach the rockers,unless blocked.
Now the scavange,there are various screws up the front to check oil flow back to the filter.
Colin.

[Martin]

Thanxs, Colin, for your concrete
oil passage review. Had more or
less done my homework with a
spare '53 or so c/case half by
squirting oil thru each passage
way to determine which way the
oil actually goes. Consolation
was your reminder that the feed
is self priming, and as the motor
smoked up in the brief run, at
least the the c/shaft may have
got fed. As I said, would have
prefered using the spare later
c/cases I saved from several
that had been demolished with
a thrown 'rod by some farm boy.
At least am lucky to have the
correct timing cover that matches
the early c/case adjacent holes.
Would sure like to know why the
'49/'50 cases oil arrangement
was changed so quickly aside from
having to update with additional
c/case centre grub screws and
external tappet lines as slow
return may have been a issue
from day one. Have the motor on
a floor test bed, hence the
plugless kicking query. Will
update you when I go over to
the garage next week.

[Mark M]

Gordon, I have found on several Enfield Twin rebuilds (admittedly later ones than your known-to-be-troubled early 500T) that it takes an unbelievably long time to see oil return at the filler cap. On my last Twin rebuild (a 1966 Interceptor) I kicked the thing for 2 minutes by the workshop clock every time I passed it for at least a month while doing other work on it, I still didn't see any oil but in seconds of firing up, there it was! I think good pre-lubrication on assembly including high melting point grease on the gudgeon (wrist) pins and regular squirting of oil into the crankshaft oil feed quill bolt is about as good as you can get.
REgards, Mark

[Colin F]

Another thing Gordon,the oil feed to the feed pump is adjacent to the sump plug so if that is to long it will cut off oil supply.A flaw with the system is the pumps will suck air before oil to so the gasket interface is critical.And those early pumps only run at 1/12th engine speed,i was advised to upgrade to the later Twin start pump but the early one is ok for normal work.And double check the quill,neoprene only supplied now must be checked for length,and contoured properly
to suit the plug champher,they seal on the ends,not the outer surface.
Also the oil return pipe on the Sand casts is only pushed into the alloy of the filter housing and can be loose,so oil may be returning but not up the pipe,so a dipstick level check while running should show you something.
Enfield changed lot's of things on these 500's,it was as if the company had never built motorcycles ever before the war,there are glaring flaws,try airfilter location pre '52.anyway regarding the oil to the rockers it flowed through a laminated gasket,naturally leaking there as well as the crankcase half joins that as you say weren't secured properly till later.And oil flows to the rocker with least resistance,so 3 of them may end up with little or nothing if one is worn out.
Let us know how you go
cheers
colin

[Martin]

Gentlemen, am quite gratefull for
your support as can identify with
all the points you raised with
having read pertinent references,
and comtemplating the c/cases
over and over. First MARK, 'twas
Good to be assured long filter
fill up time is normal regardless
of the model as I know you have
rebuilt several from your previous
advice. One wonders whether you
have to 'pump them back up' for
every prelimary start if motor is
left dormant for any length of
time. You can be sure I will be
squiting oil up the quill bolt in
ample amounts regardless until
wsome action is evident. COLIN,
Thanxs for your further tips as
there is no way I would have had
confirmed out here what you well
covered. 1)Luckily have the pen
and ink cut away superb drawings
that accompanied the original
'Motor Cycle' interview with the
designer around 1949 that show
how easily the the oil drain plug
can cut off the oil supply. 2)
Also,will be careful with gasket
sealing for air sucking in as
Norm had mentioned earlier. 3)
Did not realize the importance of
neoprene plug's length and contour.
4)Think I threaded the oil return
pipe into the cast oil chamber with
a 1/4' tap and die as it was flopping
about beforehand.5) Had jettisoned
the original pipeless cyl/heads as
some hick had broken many of the
fins and the barrels were damaged
with a thrown conrod. Had built up
sexy tappet oil lines with copper
pipe and endless brass fitting which
I can sebeing in vain if all the oil
simply goes to one tappet. Whole
scenario is like my own triple bypass
and Pacemaker. Flawed! Thanxs indeed
for both of your time as it has given
renewed interest