What's the reason for the wave phenomenon?

[wanivmax]

Weaving
A wave-like fluctuation symptom that can occur on straight or curved lines and typically occurs at an average speed of approximately 140 km/h (90 mph), varying in severity.

I'm riding the vmax1200 gen1 2005 American specification. If you run over 140 from some point on, you'll get a wave phenomenon. I'm nervous because the back is wavy in an s-shape. Currently, I've replaced the rear swing arm left and right bearings, the final gear assy, checked all wheel balance, and replaced the rear suspension. What's the reason for the wave phenomenon?

 

[Fire-medic]

Many people say their bikes have some instability of some sort. Wear of suspension components over time, and tire choice and then wear can make this happen.

The best things to do are to use a factory manual to check the steering head bearings for wear and proper torque, and the same for the rear swingarm. Adding aftermarket front end components like Race-Tech cartridge emulators, wave-washer stacks which take the place of the damper rods' function in the fork downtubes/sliders, and their replacement fork springs, sized by weight range, can help. Replacing worn steering head bearings and torquing the fork fasteners according to the service manual helps make things better. Choosing properly-sized tires with a softer rubber helps handling. The 'touring' type of tires have harder rubber, which makes them last longer, but grabbing a handful of throttle is more-likely to break the rear wheel loose, especially if you are cornering 'enthusiastically.'

For my $ the best investment in improving a generation I VMax is to convert the wheels to allow you to use a 3-1/2" wide front tire in either 17" or 18", and a rear tire in the range of 5-1/2" and either 17" or 18". The Tire choice with these changes will allow you to run radial tires. Radial tires makes a VMax work much better. Combine the front end improvements mentioned, with the rear end changes, and your bike will be as good as it gets.

Other choices people make are a front end fork brace, gussets added to the frame, the ones welded/bolted to the area between the under the seat to the front downtubes are popular. Another thing to do is to use either Delrin or aluminum inserts in-place of the rubber engine to frame mounts. Another addition is to notch and brace your swingarm to allow a 6" wide wheel, and to add stiffness to the rear swingarm.

When you're approaching the 100 mph speeds, remember that you don't have a fairing like a sportbike, and your near bolt-upright position, and the height and width of the handlebars all affect your handling dynamics.

Break out your wallet!