just got a 1974 dt 250 in nice shape it starts up easy runs and revs up good in neutral , when u put I in gear and give it gas it misses or breaks up , it has a pulser CDI ignition . any ideas what could be wrong ?

Clutch drag? Gearbox issue maybe 

 

What exactly do you mean by misses/breaks?

Hi roy "   the DT250 was POiNTS  up to 1980,.  is it after market system ?    I think  it would be carb more than CDI,,   as there reliable,

Sounds like a DT250 A , have you checked behind the magneto , 250 and 360 have a tendency of rusting due to condensation.

Its also well worth checking the carb and making sure the jets are clean and the floats are the correct way round and the levels are correct.

 

TTB