Has anyone done this and if so how does it affect the low rev vibration? My understanding is it helps in high revving. Is what this guy in this video takes off a good indication of what I can take off my Savage flywheel?
https://www.youtube.com/watch?v=XvlliZrEAow

zipidachimp wrote on 01/20/15 at 13:04:56:

Faster acceleration I think.

I was advised by my local bike shop to try it. I am seriously considering trying this. Considering our engines put out very low HP I don't think a lightened flywheel will hurt our transmissions. If they do our trannies must be made from plastic.

Suzuki left so much room for improvement ie Jets,exhaust, etc that we take advantage off why ignore the flywheel which with a little lightening can proved major gains.
https://www.youtube.com/watch?v=KHz7L35Y454

The heavy flywheel stores rotating energy, and helps to even out the power pulses and the compression stroke.....it makes the engine run smoother.....most noticeably at lower rpms.

Would the bike be quicker with a lighter flywheel....Yes.

Can the clutch handle your 97mm piston and a light flywheel...Dunno!

Can you lighten the flywheel a bit.......Sure!

When I was playing with VW bug engines...we lightened the flywheel to make them quicker.  When my friend had a 1973 Suzuki TM400 motocross bike - they bolted an extra flywheel weight on them to try and make them less likely to spin the rear wheel as the power just came on to suddenly.

Flywheels store energy, and do help you to get moving from a stop.  When you lighten the flywheel you have to slip the clutch a bit more, or use a few more revs to make up for the loss in stored energy....the engine does become easier to stall when pulling away from a stop. Maybe Suzuki has so much flywheel to help new riders avoid staling the engine while they learn how to ride. The Savage has a heavy crankshaft, heavy flywheel, and heavy rotor....most likely you can lose a little bit of that weight and still be OK - I have no idea how much, and you need to be aware that the farther the distance from the center of the flywheel....the more energy is stored.  (Remember how the ice skaters speed up when they are spinning and they pull their arms in?  They spin faster as they reduce the "moment of inertia" when their arms are no longer swinging on a long path and are held close to their body).  The end result is that if you are removing weight from the outside diameter of the flywheel.....it will reduce the inertia a lot.

Will you be the first one to try it on this motor....Most likely.

PS....If you want to see what happens if you lighten the flywheel too much.  Go to the garage and find your push mower.  Turn the mower on it's side, remove the blade, turn the mower upright.......now try to pull the starter cord.  With no momentum....you most likely can't get the engine to turn over a single revolution.  Push movers have an aluminum flywheel and use the blade mass as the flywheel.

Thank you Dave and Justin very informative as usual.
I see that what the guys in the videos call a fly wheel our parts list calls a Rotor.
Sorry for the confusion Title should read Rotor lightening.

Serowbot wrote on 01/20/15 at 17:13:13:

But what if I did both. Im really curious to see if a lighter rotor/flywheel stator will have any benefit. I already have a spare one which my buddy can mount in a lathe.
Now that we are clear thats its the rotor and not the actual flywheel thats being lightened, there shouldn't be too much issue with crank balance and such should there?

Trials bikes used to have a heavy flywheel just to store energy.  Makes it easier to pop the clutch and make the bike hop up things with a tiny motor..  Personaly, unless you were planning on going to try out for the Isle of Man race, I would leave the flywheel alone.

Nothing ventured... nothing gained, as they say.  I would be interested how it works out.