81-82R engine in 84 Trike?

[whiteman350x]

What are the differences in the 81-82r motor vs the 83-84r motor? My friend is looking for a spare bottom end for his 84. Will the 81-82 motors drop in?

[ATCWRENCH]

the motors are pretty much the same other than the shifter output shaft is longer on the 81-2 and the 83-4. Now if he can get a hold of an 83-4 transmission it will drop right into the 81-2 bottom end and then he will be set to go.