2 different engines with same problem.
After rebulid with new bearings and seals
They drive perfectly.
But after about only 30 km driving they start leaking quite amount of transmission fluid from vent hole.
Not leaking when stationary and engine off.
Tuned with 3,5 hp cylinder-set. But using stock old crank.
Can my old cranks be the problem sealing the crankcase from the transmission case?
Anyone have experience with this?