Machining stock flywheel

[svr]

I thought I saw someone on here offering the service on your suck flywheel. Anybody know who does it and can it be done on a lumped flywheel. 3phas 99 m900 fwiw.
Thankee

[koko64]

What country do you live in?

I know a few people that will lighten a flywheel but I'm in OZ. Mine has the trigger lump ('95 900). It was carefully machined down to weigh a little less than half it's weight and still maintain it's integrity for sixty bucks. With the light flywheel and other mods, the bike makes my shift light go crazy through the gears.

What about a Nichols flywheel? They are very light but some say that too light a flywheel is too snatchy at low revs. I had a '92 superlight with a DP flywheel.  With 39 FCR flatslides and high compression pistons I found I had to be careful getting on the gas while leaned over.

Here are some approx weights of flywheels I have tried with similar engine mods and how I felt the engine characteristics to be. The mods were FCRs, porting, high comp pistons, open air box/pods, 15/39 gearing, very light clutch, pipes and Dyna coils:

Stock flywheel 1.9kg/4.2lbs      Smoothest but sluggish (relatively), nice when there isn't much traction (cold/rain)
Machined stocker 0.9kg/2lbs     Smooth but spins up quickly as I described
DP alloy flywheel 0.6kg/1.3lbs   A little snatchy but wheelie heaven, but show respect with throttle control
                                          when leaned over.                                                                                                                                   I had to wait to get onto the fat part of the tyre before I got on the throttle so I wouldn't be highsided. This was also exacerbated by the nature of Flatslide carbs. Stock CV carbs would 'get on' softer. I decided to try a moderate weight next time I had a bike with FCRs.

So it all depends on your preference and riding style


Check out the bikeboy.com site and look up the general Ducati section about light flywheels.

[koko64]

If Nichols flywheels are cheap enough.. If I had the money I would try one and show the rear tyre some respect when cranked over, especially in the cold. Even lighter than the old alloy DP one that I had on my Superlight.

It seems that about halving the weight of the stocker is about as far as you can go and keep enough meat to keep it safe, (from what my friend told me who did the work). I'm pretty sure I have had a similar conversation with Brad Black about how far you can go with machining it down. That thing's gotta be balanced right with no weak points. If you can't find someone that really knows what they're doing I would buy a Nichols one and try it out.

How are the FCRs going?

[svr]

Koko thanks for all the great info!  I'm leaning towered a Nichols as of right now. I thoight someone on here would machine the stocker for u but maybe that was the other site.  So is there a definitive answer on engine braking?  Seems to me that it would be more since the engine would speed up and down faster. Dunno but seems like people say both ways. The fcrs are still a work  in prog. I just traded exhaust with yuu and am waiting to get that bolted up before playing with jetting again. I bought some new manifold rubbers cuz I just could not get them to not leak. I don't wanna ruin these new rubbers by overtightenibg. Got any tips?
Thanks

[koko64]

Koko thanks for all the great info!  I'm leaning towered a Nichols as of right now. I thoight someone on here would machine the stocker for u but maybe that was the other site.  So is there a definitive answer on engine braking?  Seems to me that it would be more since the engine would speed up and down faster. Dunno but seems like people say both ways. The fcrs are still a work  in prog. I just traded exhaust with yuu and am waiting to get that bolted up before playing with jetting again. I bought some new manifold rubbers cuz I just could not get them to not leak. I don't wanna ruin these new rubbers by overtightenibg. Got any tips?
Thanks

My experience was more engine braking with a lighter flywheel. It was very noticeable with the DP alloy one and The Nichols site mentions the effect too. I honestly don't notice much difference with the machined down flywheel. Interestingly, my feeling with the bike was that a light clutch (Vee Two and Barnett components dropping about 1.7kg/3.75lbs), helped offset /reduce the increased engine braking. I don't understand the theory fully, but that was my experience and would welcome someone explaining it to me.

I have heard people say that a light flywheel decreases engine braking, but that has not been my experience on big V-Twins.

I am considering getting a Nichols flywheel to compare with my machined one, but that would be if I find some spare cash. I'm curious as to what your experince is a very light flywheel.

I tightened my manifold rubbers pretty tight and wasn't concerned as they are pretty chunky. I suppose splits and cracks on old rubbers would be the thing to look out for.

[Armor]

Its much easier to match revs and downshift smoothly with a light flywheel.  Quicker engine response and will pull power wheelies easier.

[Düb Lüv]

i have an aluminum flywheel on my 95 m900. one thing i've noticed is that the engine kinda farts on low RPMs revs. i only notice it at idle(mine's about 1150-1200) to about 1300 to 1400 rpm. after that quick reving heaven.

[Raux]

I know this is old topic.
But I'm looking at the SSR lightweight flywheel for the 696.

Anyone have experience with a smaller motor and light flywheels?

[Düb Lüv]

I know this is old topic.
But I'm looking at the SSR lightweight flywheel for the 696.

Anyone have experience with a smaller motor and light flywheels?

i dont have any personal experience with your question, but i kinda shied away from aluminum flywheels after reading horror stories about the crank stripping out the aluminum splines on the flywheel. i stayed safe and had the stock flywheel machined down. shaved 3lbs 5.2ozs over stock.

[TAftonomos]

I thought I saw someone on here offering the service on your suck flywheel. Anybody know who does it and can it be done on a lumped flywheel. 3phas 99 m900 fwiw.
Thankee

I've not done a 99' M900 flywheel before, but I'd be happy to.  PM me.

[atomic410]

i dont have any personal experience with your question, but i kinda shied away from aluminum flywheels after reading horror stories about the crank stripping out the aluminum splines on the flywheel. i stayed safe and had the stock flywheel machined down. shaved 3lbs 5.2ozs over stock.

this is why most guys i race with just machine them down.  i've seen a few engines get destroyed when the alm ones chunk

[atomic410]

add a quick cam or throttle for full effect as well.

[Raux]

Actually i hav the electrean quick throttle cam

Have you used the lightened flywheels on the smaller motor.  i only ever here about large case motors with them

[rule62]

Machined down stock flywheel (ending weight = about 1.5 pounds) on my little 620 was the best mod I ever did. Most bang for the buck, next to the 14t front sprocket.

[Raux]

Machined down stock flywheel (ending weight = about 1.5 pounds) on my little 620 was the best mod I ever did. Most bang for the buck, next to the 14t front sprocket.

awesome, thanks.