Let me start from the begining.
We had a 78 engine in one of our choppers ( MY DREAM Street Chopper magazine 1978) that had been gone through before we got the bike. while riding, fourth and fifth gear would pop or jerk like the gears were missing teeth. We had a spare 75 engine with a bad top end and the top left rear mount tab broken but still worked. chopperjim swapped top ends and road the bike for ten years. In 06 we pulled it down for a complete restoration. Not knowing the difference in 75 to 78 at the time, we dropped both engines off with a friend who had a mechanic that said he could do what we asked. That was put the good 75 trans in the good 78 case and also tell us what the problem was in the first place. When we picked up the engines the guy tells us all he found was that a thrust washer was missing from the 78 gear set. he puts the 75 gear set in the 78 case and when he trys to install the 78 final drive set it wouldn't fit so he installs the 75 final drive set and tells us he couldn't find the " shaft sleve/spacer"????????? We get everything home and set everthing out on the shop floor and start studying. Then I notice the difference in the cases and in the final drive sets and realize we're screwed.
So my questions are ( after down loading diagrams from the ENGINE page) is there an easy way to tell what gears are what 75/78 size, # of teeth etc.? and what realy was making the 78 trans pop? could it have been the chain binding because of the difference in the sprocket alingment?
Seeing that the trans is close to the first things to go in the case and the only way to tell if it's right is to have it in the frame and riding it.
What can I do?
We had a 78 engine in one of our choppers ( MY DREAM Street Chopper magazine 1978) that had been gone through before we got the bike. while riding, fourth and fifth gear would pop or jerk like the gears were missing teeth. We had a spare 75 engine with a bad top end and the top left rear mount tab broken but still worked. chopperjim swapped top ends and road the bike for ten years. In 06 we pulled it down for a complete restoration. Not knowing the difference in 75 to 78 at the time, we dropped both engines off with a friend who had a mechanic that said he could do what we asked. That was put the good 75 trans in the good 78 case and also tell us what the problem was in the first place. When we picked up the engines the guy tells us all he found was that a thrust washer was missing from the 78 gear set. he puts the 75 gear set in the 78 case and when he trys to install the 78 final drive set it wouldn't fit so he installs the 75 final drive set and tells us he couldn't find the " shaft sleve/spacer"????????? We get everything home and set everthing out on the shop floor and start studying. Then I notice the difference in the cases and in the final drive sets and realize we're screwed.
So my questions are ( after down loading diagrams from the ENGINE page) is there an easy way to tell what gears are what 75/78 size, # of teeth etc.? and what realy was making the 78 trans pop? could it have been the chain binding because of the difference in the sprocket alingment?
Seeing that the trans is close to the first things to go in the case and the only way to tell if it's right is to have it in the frame and riding it.
What can I do?

