The XS1100 engine does not transmit power directly from the crankshaft to the clutch basket/input shaft, but rather via a wide hy-vo chain onto an intermediate jack-shaft with a cush-drive damper.

To make adequate power most modern motorcycle engines of the day including the XS 750 had simple hemispherical combustion chambers with domed pistons.

This design has a major drawback in relatively long flame travel during combustion and therefore requires much spark advance, which can cause severe pre-ignition (knocking) in high-performance engines.

The XS 1100 however remained the strongest production motorcycle in terms of torque and in-gear roll-on performance until the arrival of the Yamaha FJ series in 1984.

[3] "Nobody gets far riding the XS Eleven before they become acquainted with the fact that it's strong; we had ridden ours over hundreds of open-road miles before going to the drag strip and knew it was a bullet.

"When this behemoth of a motorcycle actually hits a corner at anything approaching interesting speeds then it takes a good deal of muscle to lay it down.

"[6] Testers of the day all echoed the same story: "The XS1100 was a solid bullet in a straight line, but cornering at high speeds was done at your own risk.

The XS Eleven was the most powerful mass-production motorcycle of the late 70s and posted superior performance numbers compared to its competition.

In 1979 Yamaha followed the growing market trend for "factory custom" motorcycles by offering the XS Eleven "Special" (SF Model).

The XS Eleven Special sported pullback buckhorn handlebars, a stepped seat, a 16-inch rear wheel, a smaller capacity tear-drop gas tank, a round instrument cluster, round lighting fixtures and an adjustable suspension with new air-assisted leading-axle front forks creating the "factory custom" or "soft chopper" look, a forerunner of the modern cruiser.

The XS Eleven Special sold well in the US despite complaints about the poor ergonomics "What that translates to is a bike with an awkward riding position but generally excellent road manners.

In fact, what irritated the staff mostly in how the bike rode and handled could be traced to the handlebar, which, although certainly as trendy as disco dancing, was not what the ergonomics doctor ordered for precise, comfortable control.

Beginning with the 1980 model year from September 1979 numerous changes were made to all US-market XS Eleven engines to comply with more stringent US emission regulations.

The EU/RoW engines retained the more performance-oriented specs (Heads, valves, pistons, carburetor jetting, and ignition tune) of the "early US models throughout their entire production.

The emission-related changes of the late model US XS Eleven were never introduced in EU/RoW bikes since such emission regulations did not exist outside the US.

The rider footpegs of the EU XS 1100 were mounted on different rear sets that positioned them higher and further back on the frame for more clearance.

Yamaha recognized the change in market demands for more sporty bikes and built the XS 1.1 S to bridge this gap until the new FJ 1100 was ready for sale.

"A key component of the race from the very start was that the motorcycles had to be completely stock, exactly as available the day after the race in dealers’ showrooms around the world, and they were rigorously inspected in both pre-race and post-race scrutineering to ensure that they were"[1] Flack of Motor Sport Retro wrote: "While the new CBX1000 and Suzuki were out and out sports bikes, the shaft-drive XS1100, affectionately called the 'Xcessive', was more of a muscle bike come tourer.

In the 1979 Castrol 6 hour, XS Elevens finished second (Greg Pretty, Jim Budd) third (Len Atlee, Gary Coleman) and fourth (Roger Heyes and D. Robbins) The XS Eleven's successful racing career was a remarkable achievement considering its shaft drive and long-distance touring capabilities.