plunger A10 thickie time

[chaz]

ok, hands up, Ive always been unit 350, 500 and 650 powered. bearing in mind that, I was thinking  the same for my A10.

today, ( Ive owned the bike for 12 years, most of which its been parked up) ,   Ive been looking at oil leaks. consulting the parts book, for a 1952 frame and 1950 + engine, the primary , to my mind is leaking oil. Ive only ever changed or topped up engine oil. but primary always seems above lower  chain run level, the engine always wet sumps, the reason it never gets used (that and time).

my question to those more familiar with pre unit motors, is there a gasket or seal that has failed around the crankshaft to allow oil to escape from the wet sumping sump?
Im presuming, as Ive never topped up the gearbox, the excess oil has not come from the usual culprit final drive bushing. This has always been my thought as unit bikes suffer as its always the source of leaks.

currently trying to get insurance to give it a run but being altered , its a contentious problem.

[DAVE BRADY]

Hi Chaz,

I believe that the early plunger engines did not have a seal on the crank case and that it was possible for oil mist from the crank case to get in to the primary case.  Periodically the primary case level plug would be used to get the level correct.  Obviously it would be a very small amount of oil in a regularly used and non-wet sumping engine.  When it has wet sumped have you also drained the primary to see how much oil is in there?

Dave.

[chaz]

thanks Dave,
Ive never drained the primary even after wet sumping. So thats why its filled up then. did the A7/10 crank bearing have rubber seals?.


As I said, its been the victim of a vicious circle, rescued from a barn that caught fire, used for a couple of weeks then due to work and the business, I either have to drain the sump, change the fuel or charge the battery when I want to start it.
Now the Triumph chop is finished, The A50 is in progress, there are more bike riders at work now than before, I thought I would get it out for the summer.

[DAVE BRADY]

Hi,

No seals in the bearing as it is the two part bearing as in all A10s.  When SRM do an end fed conversion they modify the anti-syphon valve behind the oil pump so that the ball and spring can be replaced without having to split the cases.  With great care this could be done without a strip down.  Perhaps using a reduced vacuum cleaner hose to suck all the bits of aluminium away.  Once opened up the A65 ball and spring is used.  It may cure or at least reduce the wet sumping.

Dave.