Motorcycle Repair: 1974 Triumph T140, triumph t140, british bikes

Question
QUESTION: Bought bike a week ago, goodshape (engine recently rebuilt)
NO SPARK, any Ideas.

Thanks

Kenny

ANSWER: Kenny,

-the problem depends on what kind of ignition
setup you have. If it has contact points that is the
first thing to check. They should open about
.015" and with a timing light, fire with the
flywheel marks aligned at 2500 RPM.

-If it has a boyer or other electronic type ignition
it could be a low battery or loose wire or poor
connection. Your coils should have power to them,
but british bikes often have a positive ground
system which means the power may be on the negative
coil wire with positive going to the contact points.

-Have a look at your battery and see if the positive
terminal is grounded to the frame, this makes
it a positive ground system.

-I have included some links which may help:
http://www.britcycle.com/Manuals/charging_problems.htm
http://www.britcycle.com/help.htm
http://www.northerneagle.ca/index.htm
http://www.britbike.com/ubb/noncgi/ultimatebb.php?/ubb/get_topic/f/13/t/007625.h
http://www.triumphrat.net/


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QUESTION:
Help


I noticed that one exhaust pipe is fowled with oil, along with that spark plug.  The otherside is burning clean. Any thoughts or are we talking rings or valve guide.  I was told (from a reliable source the engine was recently rebuilt)

Any Ideas.

Kenny

The bike has sat for a while

Answer
Kenny,

-does it run okay with a new plug?
possibly it has been misfiring for
awhile. Are you sure it is oil or
could it be a flooding carb? (Amals?)

-Valve guides and rings should have been checked
on the rebuild if it had one.

-I think it might be a good idea to
have the compression checked and a leak down
test done to find the source of the oil leak.

-a leak down test involves a fitting
in the spark plug hole for air pressure
and then putting the engine on the compression
stroke and listening for air leaks as you
move the piston up and down it's bore.

-if the compression is low it may be a damaged
ring or cylinder.

-an oil ring may have broke on reassembly
if they were not very careful.
the rings are very stiff on these british engines
and can be broken easily on sliding
the cylinder back on.

-valve guides may be worn but usually don't
cause that much oil fouling.

I just noticed that you said it sat awhile,
is it possible the rings are rusted or stuck?