The engine is there with these explosions going off inside of him causing him to vibrate and carry on. That carry on translates through the drive line in rotational force and the rotational force if not smoothed out would be….well…..rough. The flywheel serves as a smoothing device for the inertia generated by the engine.
Think of a bowling ball, its round and heavy, if you roll it and walk behind gently kicking it with each step chances are it will remain close to a constant speed regardless of how hard you kick it (Your foot will be fairly second hand though). Now instead of a bowling ball think of a soccer ball, you walk behind that and gently kick it with each step/kick its speed will increase greatly before decreasing and giving you time to catch up and kick it again.
My point is the lighter the ball/wheel the easier it is to spin it.
Enter Ducati with their flywheels, less is more more is less who knows there have been many debates on the “right” sizes for a flywheel. Obviously the lighter a flywheel the less weight you have spinning around inside your engine but also the less “streetable” the engine is going to be. But with less rotating mass the engine is going to spin up more quickly. But this comes at a cost through rough idling & easy stalling. The heavier a flywheel is the more smoothed out the inertia is but also the slower the engine is to “spin up”.
There are many options for flywheels, In my research leading up to purchasing I came across the following flywheels and their respective weights:
DS Engined Hyper: 1.898 Kg
New Hyper EVO/796 (848): 0.99 Kg
Ducati Performance: 0.960 Kg
Nichols MFG Flywheel: 0.584 Kg
MPL: ???
Machined Down Stock 0.79 Kg
You can clearly see the difference in chunkiness here in this comparison pic
Flip SideThe Nichols MFG flywheel & nuts (Its recommended to use the better quality nuts over reusing OEM) came in at $270 to my door. While the machining option is less than half that you cannot restore your bike to standard & its offline while the part is being turned down. I didn’t want to have my bike off the road for that long and wanted a simple swap over performed with the 12k service. Based on that fact and also that I had read plenty of positive feedback using the Nichols flywheel on Hypers I went with it over the MPL. This was mainly because the MPL option (although slightly cheaper) didn’t seem to have as much online feedback for use with hypers.
Here is some shots of the respective OEM & Nichols flywheels on the scales (for the purposes doing scients stuff)
And the bling
Upon picking up the bike these are my initial thoughts.
I started up the bike, went to take off and of course (you knew this was coming) stalled it, its a little lighter off idle so you need to give it the slightest amount of throttle where as before I’d just let the clutch out until the RPM dropped then twist the throttle.
I started it up again and bumped it down the drive and onto the road and cautiously accelerated towards the first bend (2 doors away not even time for a gear change) I then turned the left hander and immediately felt the bike was lighter and dropped easier. I continued through the corner then gave it a squirt and knocked second and I could start to tell the thing had more zip. I down shift as I approach the stop, I can already feel the idle is a little more rougher than before & dare I say slightly angrier.
I pull up at the stop sign before a left onto the highway. Its probably 200 metres, only one upshift before I’m at the lights to U-turn back towards the direction I want to go. Itching to give it a bit more of the berries I open up the throttle and feel the front end lighten before shifting and cutting the throttle.
Knowing that I could now give it some on take off made the green light take 3 times longer. Was I still being cautious at this stage? Slightly. The green came up and I turn the opposite way, as I straighten it up and give it a fist full of throttle. This time I shift my body forward as she hooks up and I feel the full RPM range and how much smoother and faster it approaches redline. I laugh in my helmet as I shift up a gear and close my visor.
Its good, really good but also rougher and harder work down low in the slow moving traffic but once you get on the gas its brilliant and I’ll happily sacrifice a bit of low speed rideability for that faster spool up.
A few weeks later and now paired with the 2-1 SC project pipe & my intakes its an absolute animal to ride (and thats just how I want it).