Thanks Harold, yet I confess that planning is often only the prelude to failure & ultimately to discovery. Just a day after disclosing I'd use the excellent Sportsman idler on the motor side I found that an extra bracket would be required to place the sprocket at the proper height or I could just use a smaller roller (or idler sprocket) partially hidden by the chain stay & the adjustment tab provided with the Sportsman frame, which worked out well.
At first I was bummed out that I'd so misjudged the chain slope from the 14 tooth bottom bracket sprocket to the 40 tooth final drive sprocket which slope is of course much shallower than it was on the 56 tooth sprocket used on the Simplex build. The result was chain rub on not only the chain stay but on the side of the drive off stand as well. If you recall I had much the same issue on the pedal side but caused in reverse by the much smaller diameter pedal sprocket required to clear the engine case. On both sides of the bike I failed to recognize that chain slope angle was going to create problems. The good news on my chain setup is that I've got 90% of axle adjustment remaining at the drops and I've great side to side tire to frame clearance with the wheel true and centered.
Harold I suppose a few posts regarding the basics of setting up the triple chains from a variety of builders would be beneficial to not only novices but experienced builders as well. I offer my previous explanation as proof that multiple chain setup can be a design headache even with planning. I've stated previously that I prefer my motor mounts to not adjust fore and aft. I want the motor & frame locked in position. I do use spacers side to side for initial motor alignment, but once spaced and bolted in the motor is not moved until major engine work is required. The Keystone cradle design of the current Harley Peashooter allows the engine to be dropped and left in the cradle for much bench repair & then reinserted into the frame with no engine to frame realignment required! The Simplex Copper Gator would require both front to rear and side to side motor adjustment of the 125 cc 5 speed case after removal from the frame.
As to the coaster brake lever to Heim joint adjusters; I use these in all kinds of setups, big suspension links, throttle linkage, board track saddle supports etc. on automotive, trucking and bikes as well. Handy little critters that look trick as well.
My observation; no one knows even most of the tricks when it comes to things mechanical. Share something amazing & useful! Rick C.