Lightened Flywheel

[Schwanger]

I decided to pull the engine so I can bring it inside and work on it over the winter.  I've thought about having the flywheel machined at work.  I know Vino and Blckduc have either gotten aftermarket or machined flywheels, how do you guys like them?  Any issues?

The second part of this post has to do with removal of the flywheel.  For anyone that has removed their flywheel how did you remove the nut?  Does is require an impact or did you use a cheater bar?

[fasterblkduc]

I used an impact but a a cheater bar with a dead blow would work. You can borrow my impact if you want.

I have a machined one and Ulf has the aluminum aftermarket one. From what I've heard, the aluminum ones wear out the gear teeth in time so your starter will eventually slip.
It will make a nice difference when getting on the throttle. It spins up quicker. I also reduced my rear wheel hop from hard downshifts so I did less backing into corners. Since it spins up quicker, you will get to the rev limiter faster. I found myself needing to do short shifts between corners because I would hit the limiter and stop making power. It was nice because I dropped some laptime but it meant extra up and downshifts. I don't know how much benefit you will get on the street but you may have to adjust your idle because at low idle it may want to die. But again, I did not ride mine on the street so Ulf might know more about that.
I give it a big  as far as performance. Good bang for your buck. If you can get it on a lathe at work, then do that.

[atomic410]

What would the advantage of this be for a streetbike?  I understand it in a racing situation but wouldn't it hamper relialibility really?  Relialibility and race engines not such good friends but street riding and relialibility should be best buds imo.

[Schwanger]

What would the advantage of this be for a streetbike?  I understand it in a racing situation but wouldn't it hamper relialibility really?  Relialibility and race engines not such good friends but street riding and relialibility should be best buds imo.

It has the same benefit on the street, basically I want to make my bike quicker without a displacement/compression change. 

How will it affect the reliability?  I understand that I will have to raise the idle, no issue there.  By machining the stock steel flywheel I'm planning on going from 4.5 lbs down to between 2-2.5 lbs where the aluminum ones are 20 ounces or less.  I don't know MOI's for the flywheels but I'm certain the machined stock flywheel will be higher than the aluminum ones.  The rotating assembly should have been balanced without the flywheel, so I shouldn't have any issues with a crankshaft imbalance.

Just a little FYI, because of the 90* included angle between the cylinder, the pistons are exchanging kinetic energy between themselves so a flywheel with a large mass moment of inertia isn't need like in a boxer engine or a v-twin with a lesser angle.

[atomic410]

I guess my question was the relialilibity of a machiened stock one vs the aftermarket piece and its overall effect on the engine.  I get it now.  good lesson.  Good luck

[Major Slow]

It has the same benefit on the street, basically I want to make my bike quicker without a displacement/compression change. 

How will it affect the reliability?  I understand that I will have to raise the idle, no issue there.  By machining the stock steel flywheel I'm planning on going from 4.5 lbs down to between 2-2.5 lbs where the aluminum ones are 20 ounces or less.  I don't know MOI's for the flywheels but I'm certain the machined stock flywheel will be higher than the aluminum ones.  The rotating assembly should have been balanced without the flywheel, so I shouldn't have any issues with a crankshaft imbalance.

Just a little FYI, because of the 90* included angle between the cylinder, the pistons are exchanging kinetic energy between themselves so a flywheel with a large mass moment of inertia isn't need like in a boxer engine or a v-twin with a lesser angle.

Pretty fancy engineer talk.

[Schwanger]

Pretty fancy engineer talk.

I had thoughts of differential equations dancing through my head as I wrote it.

[Major Slow]

I didn't know equations come with differentials, but there are a lot of things I don't know.

[Vino900]

Oh the memories from college - Differential Equations.............mmmmmmmm
Back to reality...  I did not use the aftermarket aluminum flywheel after all.  Fred at Silverback talked me out of it and he machined down the stock one.  The motor spins up much faster and I loved it on the track.  On the street it did not make much difference in normal operation.  BTW I did not adjust the idle speed and I never had any problems starting when cold.  A few moments on the choke and then just happily idling.
I highly recommend it for spirited riding.
 

[MonsterMitsu]

I just Lightened my flywheel last winter on my 2004 1000DS. Used the stock one and just machined it down. Silverback did all the work so I'm sure he could answer any questions you had.
But here's what I understand about it.
-The stock Ducati FW is over built and tough as nails so taking some off of it doesn't hurt it. And it's economical.
-It doesn't give you more HP.
-It will help your engine wind up faster. You notice a little when you twist the throttle when it's parked but when you take off from a light you not gonna notice it so much.
-saves a little gas.

Over all I'm glad i had it done while i had it apart for maintenance.

have fun!