Comfort, like beauty, is in the eye of the beholder. It's all about what you like. This soft science we call ergonomics describes the bike/rider interface, and is determined by a wide range of variables starting with bike layout. High handlebars or low clip-ons; footpegs close to the seat or far away; a saddle built for three weightlifters or insufficient for a gymnast-you'll find a broad spectrum across motorcycling. They all are made to support the human body and provide a platform for control and comfort, but the almost uncountable variables of bike and rider make a perfect fit fairly rare.
Don't take discomfort for an answer. There are dozens of ways to improve the way the bike fits you, which is better than settling for the other way around. Start with the small stuff. Adjustable brake and clutch levers give riders with small hands a shorter reach for better feel. For a more comfortable wrist angle, rotate the levers up or down on the handlebar, but don't stretch the brake hose or kink the clutch cable in the process. The reach from bar to hand control should be natural, requiring little or no repositioning of the hand to accomplish.
The shift lever and brake pedal can be angled differently, but don't move them so far that shifting and braking require awkward foot motions, or that your boot rests on the brake pedal as you ride. How much you can change depends on the bike. Those with shift levers bolted directly to a splined shaft offer relatively few useful variations, while bikes with linkages give you more freedom; just be sure your bike's linkage doesn't hit anything or bind up with the new adjustments.
With the footpegs on some bikes high enough to make a hobbit feel cramped, even younger knees cry out after an hour in the saddle. There are footpeg-relocation kits for most bikes-run a Google search or check at your brand-specific online forum-that can fine-tune peg placement. The biggest drawback to moving the pegs by way of a displacement arm is that the foot controls may not line up properly, even with adjustment. But that's still better than daily cramps.
HeliBars are a simple and inexpensive way to radically alter your riding position. This mo
Moving the handlebars can be easy or hard, depending on your bike. For motorcycles with clip-on bars, there are several aftermarket solutions-from Convertibars, GenMar, HeliBars, Renthal, Vortex, and others-that offer more bar rise, additional pullback, altered droop, or all of the above. How close the bars turn to the fairing and tank will determine how much you can change from stock, but even as little as an inch in the right direction can make a world of difference for long-range comfort.
Bikes with a true handlebar-you know, that bent tube beneath your mitts?-have more options, but watch out for fairing/tank interference (be sure to include the depth of the switch clusters in your calculations) and other factors, such as cable/hose length, wiring flexibility, and interference between bar-mounted mirrors and the rest of the bike.
Motorcycle seats are designed as much by stylists as engineers, so it's no surprise some of them are awful on long rides. Custom seats come in two varieties, off-the-shelf like those made by Corbin, Saddlemen, and Sargent, and custom-made from builders like Bill Mayer and Russell. Sargent and Corbin make their own seat bases while Mayer and Russell work their magic on your stock seat pan. Because some of the most comfortable long-distance seats are the least attractive, there are riders who would rather gobble ibuprofen than put up with a ribbing from their buddies. If you're one of them, take a look at removable gel seat pads you can take off at stops.
Wind protection isn't strictly an ergonomic issue, but it reduces fatigue over long distances. A short screen that takes the brunt of the windblast off your chest makes a huge difference, more so if it reduces helmet buffeting and noise. Get one short enough to see over so you're not flying blind in the rain or while heading into the sun. Simple changes can reinvent your ride.
If you lower your bike, be careful where and how you park it. The stock-length sidestand holds the bike up straighter, leaving it more likely to fall to the right on sloping ground, and hoisting the bike up onto the centerstand takes more effort. Shortening both stands can be an expensive and permanent fix, so make sure lowering is the way to go before you get down to it.