Shaving the flywheel

[Arigato]

I'm having some material milled off my flywheel for a little more snap.  I know some are running the pvl ignition, but has anyone else simply milled the stocker?  If so, how did it work.  I'm either going to be real happy or $250 in the hole buying a new one.   

[KXcam22]

Arigato,
 I have not shaved the stocker but have done it on other bikes.  I usually decide the OZ I want to remove then calculate the volume of mass to remove (using the density of steel).  Looks like there is enough meat on the stocker to take off a bit.  Have to watch out for the external trigger magnet which will reduce the size of the band that can be lathed away.  Works the same in reverse to add weight by machining a brass band (not the kind you listen to) and shrink fitting it over the flywheel diameter to add weight.  Let us know how you make out. Cam.

[5dracing]

I always ran lightened flywheels in my buggies, down around 10lbs. Made them run like the dirt bikes. Problem with lightened flywheels is keeping the engine idling when stopped. (if you want it too)

[doordie]

Arigato,I have a milled stock flywheel and it?s working fine for my use.
You know it change the 500cc to a nervous 250cc and hard to ride.
I will never go for PVL for mx or trailriding ,but in sanddunes, yes.

[FuriouSly]

Doordie, how much did you take off?  Ounces?  Or a just milled it to overall smaller diameter?  Thanks.  Sly

[doordie]

Sly,
I will weight it and compare to stock and take a pic of it too.
You see it at my blown engine pic! 
It spinns fast

[FuriouSly]

Thanks.  Hard to tell from that picture, probably because I keep looking through the motor at the pretty grass behind it 
Sly

[doordie]

Here are a some new pics of that flywheel.
Weight info later Sly!

[gowen]

I will never go for PVL for mx or trailriding ,but in sanddunes, yes.

The PVL was a rush through the trails! But, was pretty d**n crazy as you were dodging trees as if they were bullets. I think all KX's for dunes should have a PVL.

[Polar-Bus]

I will never go for PVL for mx or trailriding ,but in sanddunes, yes.

The PVL was a rush through the trails! But, was pretty d**n crazy as you were dodging trees as if they were bullets. I think all KX's for dunes should have a PVL.

sorry for getting off topic, but this PVL ignition, does it have a different ignition curve? I'm skeptical about performance doo-dads, but this unit seems to be a hefty gain in performance. I am surprised it's such a big gain to be had from an ignition unit.....

[gowen]

The PVL spikes the horsepower to the top at the expense of the bottom end. Really no gains, just eradicates the bottom end power and moves it to the top. 7500+rpms. The flywheel is MUCH (maybe weighs 5% the weight of the stock flywheel?) lighter. We've discussed this before, but check out the attached photo. Then look at your stock flywheel. I think it's worth every penny as long as you have open space and/or a strong leg to kick over after stalling it because you were not riding it like you stole it. 

[demographic]

Looking at that PVL with internal flywheel it strikes me that the fact that it weighs less than the standard one isn't the main point about it.

The fact that it's weight in concentrated closer to the centre would make quite a big difference even if it weighed the same (a bit like when high divers do a forward roll, when their arms and legs are out they roll slowly and when they hold them in tight they roll far faster).

As angular momentum is affected by the mass of the object (the weight of the flywheel) and the velocity (and the larger flywheel has a higher peripheral velocity even at the same RPM) even two equally weighted flywheels with differing diameters would have different amounts of angular momentum (or flywheel effect).

Err, that how I figure it anyway

[FuriouSly]

So... Arigato...  how you likin' the shaved flywheel?  I know, but the people want to HEAR!!  zoom, zoom...

Sly

[Polar-Bus]

I work in a machine shop thet manufactures all types of severe service industrial pumps. When we balance the impellers, we have precision scales to keep track of metal removal (or sometimes adding). If you guys need a specific oz. removed I could possibly help. Send me your flywheel, and I can machine it down, and document the old/new weights to whatever you want.  I know my Stealhy weight is 14 oz. And it made an awesome enhancement of torque down low, I felt little difference in "revs". If anything I do notice a longer over-rev WOT. I don't need to comment to you KX500 guru guys, when shaving your flywheel, go INCRAMENTALLY small removal rates. You can always shave a bit more, rather than have taken off "too much".
               Rich

[Arigato]

It definately made it more snappy.  Not uncontrollably, just sweet goodness.