QuestionHi there. I have a 74 Dt250. I have had trouble with it smoking lots of white
smoke while under load. I've believe I've tracked it to the oil pump needing
adjustment. My book said the gap for the pump setting was supposed to be
between 8-12 thousandths. Mine was set at around 20 thousandths. It had a
small( larger than the other 2) washer and 2 small shims. I took out one shim
and it closed up the gap somewhat, but seems like its still not small enough. I
just wanted to make sure me doing this won't mess somthing up and cause it
not to get enough 2 stroke. Thank you for your help!
AnswerMatthew,
the clearance you are trying to adjust
is the minimum preset pump stroke.
As soon as the throttle is opened the
cable should turn the pump cable wheel
and increase the stroke of the pump.
The pin on the pump and the dot
on the wheel should line up when
the throttle is released fully.
If you watch the pump when the bike
is idling you can see the pump plunger
moving very little but it should move.
If you pull on the pump cable you can see the pump stroke
increase on the plunger.
The small screw on the side of the pump with the
gasket is an air bleed screw.
The standard settings should be fine
as long as you see the pump plunger
moving slightly in and out.
Often excessive smoke can be from a worn engine or
bad crankshaft oil seals sucking transmission
oil into the engine.
Any air leaks can cause overheating,
check the color of your spark plug.
It should be tan colored if all is well.
http://www.dansmc.com/2_stroke_oilpump.htm
