No, he would be referring to changing the top sprocket in the chain case to one with one less tooth on it. Swapping back and forth from this would not be easy to do on the trail or even on the trailer.
This would drop the top speed by appx 5 mph but would allow the engine to remain at a higher rpm so it would tow a load easier.
Checking primary to secondary alignment will improve power transfer efficiency as will making sure that all the components of the drive train are in good working order [no binding/worn bearings].
Old Cat Rider
'93 Wildcat 700EFI w/ Comet 108 Pro-4 clutch & 01 ZR skid
we are all given sh*t in life, but some of us learn to turn it into fertilizer and grow from it, and some us try to fling it on others like monkeys