Difference between a 1922 Model J and JD

[Tom McBride]

HI gang,
Can someone please explain the difference between a Model J and JD?

Thanks
Tom

[Tom McBride]

I just found THIS!
Harley History - Harley JD & J Series Motorcycles | Harley Magazine - Classic American Iron Magazine

[rob]

tom a j is 61 ci a jd is 74 ci. easy way to tell is look at the cylinders.on a j exaust spigot you will see 5 fins that is a 61 ci. on a jd exaust spigot there is 6 fins. that is a 74 ci cylinder

[Buzz_Kanter]

Rob is right on the money with his response. Both are fun bikes but the JD has more power. Sort of like comparing an EL and an FL Knucklehead or Panhead.

[Dave Morrill]

Tom,

According to my spare parts book, different part numbers for the cases, flywheels, connecting rods, cylinders, pistons, etc.

[Tom McBride]

PERFECT!~
Thank you ALL who have replied!
This helps alot!