LW Flywheel

[Rudemouthsky]

Am I the only one with a Nichols flywheel that feels their cognitive dissonance kicking in right about now? Lol

I wanna say I was aware of and researched this issue before making the choice to go with a Nichols FW and was sufficiently satisfied that everything would be fine before taking the plunge. Doesn't Nichols MFG have an official response?

Ah ok now I remember...this only effects bikes with the newer 3 phase alternators.

[thorn14]

Nichols is the only aluminum flywheel I would trust if I went with one again.

[hackers2r]

There are a few of the DP lightened aluminum ones available on eBay.  But if the risk is the use of aluminum, I'm steering clear.  Also, are the Fast Frank lightened OEM ones balanced after they are lightened?

[brad black]

Also, are the Fast Frank lightened OEM ones balanced after they are lightened?

there's no need.  as long as the lathe runs true they're fine.

maybe the dp ones are just the wrong material.  i've not seen ones tightened to 270 fail, but we only sold a few before we started machining the std ones after one did what is shown above.

[MonsterHPD]

I´ve had a Kämna Alu flywheel on my M900 for 45K+ km now, with no issues.
On the rain bike (900SS for rainy track days) I´ve lightened the stock steel flywheel, also with no issues. Pretty hard steel, btw.

In a few cases I´ve heard about where the nut loosened with std. steel flywheels the crank was ruined; there were quite a few of those some years ago. I think, with the loosened alu flywheel the crank was OK, but maybe the engine got all contaminated with alu bits?

The splines are of no use except for locating the flywheel on the crank, it´s held in place by the axial force from the nut. The splines take the beating only when the axial force from the nut is too low.

Theoretically, the axial force could increase with an alu flywheel as the alu heats up and expands. Might cause some deformtion due to repeated thermal cycling, and eventul loosening of the nut, maybe..?

Anyway, so far both flywheels are still in place, fingers crossed. 

[muskrat]

10,000 miles and no issues.  Worth every penny if you like wheelies a lot.    Seriously, for me it was the second best mod I've done to my S4R