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I'm really intrigued by a flywheel that weighs roughly 15% of stock for my '95 M900. I'm curious about the pros and cons of changing to one of Nichols flywheels. Current modifications include 41mm FCRs, K&N with airbox top removed, and Forza slip-ons. Any comments?
 
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i've got a nichols f'wheel in my monster s4 and love the results. still idles just fine, revs noticably quicker and wasn't terribly difficult to install.
i've heard that if you're running large (41mm) fcr's like yourself, you may have starting/idling issues because of the loss in crank mass, but remember that there's still plenty of weight left in the crank assembly. i've also heards that for those with your setup, having dyna-coils installed for a hotter spark solve any starting/idling issues. if you go for both mods, you really can't lose.
 

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Whew...i thought this was going to be a spinoff of the flywheel 'discussion' on the E-Mail list.... ::)
 
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Whew...i thought this was going to be a spinoff of the flywheel 'discussion' on the E-Mail list.... ::)
Enlighten me. I wasn't on the e-mail list.
 
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"large FCRs" :p No, this is all disinformation. No problems with carbureted bikes idling with flywheels. None.
my bad chris... does this apply if you're running high-comp pistons? i thought i'd heard there were possible issues with FCR's + light flywheels in certain conditions and that a hotter spark was the solution.

i do agree that problems people sometimes attribute to f'wheels such as rough running or poor idling is nonsense. those symptoms are the result of poor tuning carbs/t'bodies (depending on model).
 

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I've got a light flywheel, hi-comp pistons, FCRs, etc., & I love it all.
 

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Ive got 944 kit 39 FCRs and the flywheel and my bike idles crappy but I think its a combo of reasons.
 

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Enlighten me. I wasn't on the e-mail list.
We recently had a lively discussion whether or not a light flywheel can increase the maximum RPM limit on a Duc. I , among others, represented the technical/engineering contingent......
 

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Nope. Flywheels have absolute zero issues on carb'd bikes. Well, other than helping the gas tank hit you in the chest. ;D

If anything, I found that a light flywheel can exaserbate mal adjusted TPS/idle setup on injected bikes. But still very small issue. My 916 would stall occasionally before nichols flywheel and then a little easier afterwards. Went through all the idle checks and problem went away and bike was ultra smooth. :)

my bad chris... does this apply if you're running high-comp pistons? i thought i'd heard there were possible issues with FCR's + light flywheels in certain conditions and that a hotter spark was the solution.

i do agree that problems people sometimes attribute to f'wheels such as rough running or poor idling is nonsense. those symptoms are the result of poor tuning carbs/t'bodies (depending on model).
 

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Heheh, no worries... strength of connecting rod determines max rpm. ;)

We recently had a lively discussion whether or not a light flywheel can increase the maximum RPM limit on a Duc. I , among others, represented the technical/engineering contingent......
 

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How hard is it to install one of these, does it involve really getting in there or could a not so super experienced mechanic work it out (i.e. me)?
 
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How hard is it to install one of these, does it involve really getting in there or could a not so super experienced mechanic work it out (i.e. me)?
the process is well outlined in the haynes manual (and the service manual for that matter), but i've got some pics and info here:

http://www.ducatipipemod.com/s4/mods/flywheel/

the only difficult thing is actually removing and reinstalling the retaining nut. i found using an impact wrench worked just dandy getting it out. retorquing to the 150 ft/lbs spec is a challenge. you'll have to find a way to lock the drive-train. some people make it a two person job. shift the bike into 6th gear, and have a buddy crank down on the rear brake to lock everything up while you torque away. or you can slide a 2x4 through the rear wheel to lock the drivetrain via the swingarm, but that applies a fair amount of stress on the wheel spoke. personally? i said F-IT and used the impact wrench to reinstall. am i flirting with disaster? i guess we'll find out this season!
 

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Hey, Strati, in your how-to you had the stock flywheel machined down to 1/2 the original weight to see if you liked it. If you did you were going to switch to the Nichols.

Well, you stated that you have a Nichols one in your S4 I guess you like the results. But I was wondering how the stock one performed once it was machined down? How do the 3 setups, stock, stock-machined, and Nichols, compare to each other?
 
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