22JA engine

[MMasa]

I thought he said it was a '22.

Sorry. My bad. I looked up and saw 23JDCA 808's post and saw "20JA"
I agree with Tommo. The VIN would have a D in it if it was a 74".
The base flange stud spacing will tell too. All 1921-23 61" cylinders were small base.
Mark

[Tommo]

If it left the factory as a 74 it would be stamped JDA surely.
It still could have been converted at a later date and then you do as Eric says and count the fins to decide

[exeric]

I thought he said it was a '22.

[MMasa]

74" was introduced in 1921 so my money is that a 1920 is a 61"
Mark

[exeric]

If you have cylinders with the motor; count the number of horizontal fins by the spark plug, and down to the exhaust spigot. A 61" will have 5 fins, and a 74" will have 7 fins.

[cabanadan]

Techwebus doesnt say if it is a 61 or 74. any help?

[23JDCA 808]

From http://www.techsweb.us/hdvin2029.html
Model 20JA - "A" motor F-head V-twin, 3 speed, electrical system
A group that specializes in these 1916 thru 1929 cycles: https://groups.yahoo.com/neo/groups/harleyjd/info

[cabanadan]

Just picked up a 22 JA engine. Tried searching and they made a JA engine and not lots of info out there. Is this a cop motor? Fast motor? 61 or 74 CI? there is a casting stamp on primary side 2-18 on it and a circle with what looks like wef cast into it. Does this make it an early or late motor... Any help???