The front caliper is the biggest bicycle rim brake I've ever seen. Hidden behind the engine but you can see it behind the fork on the 3800 in this pic.
About 3 o'clock from the flywheel is the Adjuster and at 5 o'clock is the left pad against the rim.
Removing the engine is a breeze. Disconnect the throttle cable, remove the bolt at each fender stay and off it comes. All 7lbs of it.
The PO claims he had the 3800 for 30 years and with all the jerryrigging and stove bolts with square nuts used for repairs, I believe it.
I may not be a restoration when it's done, but it will be right.