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Wanting to trim some fat from my stock 900ss ie flywheel -- rather than go the aftermarket (reviews are mixed on the nichols and ssr), I'd like to machine down the stocker. Fast Frank no longer does it, and waiting to hear back from Ben at Fox Performance... any other options people would recommend?
 

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Wanting to trim some fat from my stock 900ss ie flywheel -- rather than go the aftermarket (reviews are mixed on the nichols and ssr), I'd like to machine down the stocker. Fast Frank no longer does it, and waiting to hear back from Ben at Fox Performance... any other options people would recommend?
I hadn't heard anything bad about the Nichols until you just said it here.
 

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I machined one years ago. I think I removed 300g from near the periphery. I never got to install it on my Monster; another guy bought it. I heard back from him only once and that he 'liked it'.
 

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I have a local machinst turn mine down so if you hand it to a skilled lathe operator and tell them where not to cut you should be fine. I have the 900 ie versions reduced from 4 down to 2 lbs.

Nichols is the best of the aluminum flywheels but I have seen them fail as well, if you want the lightest they are your best option. A steel flywheel turned down will not get as light as aluminum but it will never fail. If you go super light you also need to keep your bike tuned as the motor has less mass to keep the motor turning at idle. A 748 build on my dyno right now has its idle turned up because we went very light on the crank,flywheel (Nichols),gears. pretty much anything that spins. if I try and get it to idle near stock idle it will stall more often than a normal motor because it has less inertia to keep it running.

Stock flywheel turned down should be 100% reliable and at 1/2 the weight you should not have any issues with idle. Best bang for the buck mod.
 

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I went thru Ben at Fox performance, and maybe I caught him on a bad day but I chalked it up to the cranky machinist syndrome, and he did everything as advertised. I haven't actually installed it yet, since I just took my bike out of winter storage today.
I currently have a Nichols and damn I love the way it revs, but yes, it too is a cranky bastard. Loves to stall, and my starter is starting to sh*t itself(I have a rebuilt starter sitting on the shelf, right beside the turned down stocker flywheel), so starting can be cranky. Although she fired up pretty damn fast after being under a tarp for 6 months.
Anyways, I am looking forward to getting this installed, and I'll sell you a Nichols in a few weeks for cheap if you want it! lol.
 

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it's a pretty easy machining job, just cut it down to 120mm od and 12mm thick. makes them about 850 grams.

the std cranks are about 4.5kg, plus the alt rotor so 1kg off the flywheel is still not a huge % change. the reduced diameter probably makes the biggest difference on a machined std one.

more ignition advance is the best way to stop them stalling at idle, if you can.
 

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The Op has a injected bike so not timing changes on that one. :wink2:

I have not seen starter or starting issues with a Nichols flywheel other than the increased chance you will be doing it from stalling. The 748 on the dyno would be fine if i bumped the idle a couple hundred rpms but some bikes (carbys) do not like that and the idle will hang up if too high. Running a superlight flywheel can be done but the bike just needs to be kept in tune and if it is out just a bit you have increased stalling issues.
 

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your making me think that I need to remove mine -chuck it up in the lathe and turn it down to make it lighter, But a question--If I lighten the flywheel on my BMW's engine braking is reduced badly, I am guessing that I will also run into reduced engine braking if I lighten the stock Ducati 900ss flywheel.
 

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your making me think that I need to remove mine -chuck it up in the lathe and turn it down to make it lighter, But a question--If I lighten the flywheel on my BMW's engine braking is reduced badly, I am guessing that I will also run into reduced engine braking if I lighten the stock Ducati 900ss flywheel.
Reducing the inertia of the rotating mass (be it the flywheel, clutch, crankshaft) increases the engine braking, all else being the same.
 
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